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 recommend valves and springs for my heads
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mjs69
Two Feathers

26 Posts

Posted - 12 Dec 2011 :  12:28:46 AM  Show Profile  Reply with Quote
Hi all

New to the forum...planning an upcoming mild street/strip 400 build and I'm starting to get down to choosing specific parts...

Some helpful folks at a more general hot rod forum have helped point me in the right direction, but I figured I'd better come to a Pontiac specific forum as well...

Ok...I've got a set of 1968 vintage 72cc D ports...a mismached set, one is a #16 and the other is a #62. All I have talked to assure me I can use them, as they are basically the same head. I've already cc'd them to verify that they are both 72ccs. These are bare castings, so I'll need all the other valve train componants...

The camshaft I'm going to run is a Lunati VooDoo 262/268, #60902. This cam has a lift of .489 on the exhaust side. Hydraulic lifters, and I'm going to use 1.5 ratio roller tip rockers.

Question #1...can you recommend a valve spring set should I use with this particular cam? Can I get a spring set with the proper pressure to fit without having to machine the spring pocket?

Question #2...which specific valves will I need for these heads? They are 1.77/2.11's....but I see a ton of different stem lengths, diameters, angles, ect....

Thanks...

Mike

Bill Boyle
Horse Feathers (Charter Member)

USA
5331 Posts

Posted - 12 Dec 2011 :  07:53:23 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
My first thought is, what valve springs does Lunati recommend with this camshaft? I'd go from there looking at the spring rate and pressure, seated and at full lift. Once you have those numbers, you can look at those springs from Crower, Crane, Comp (the big 3).

As for the length of valve to use, consider the installed height of these various springs. Some may require longer valves others may not.

I'd try to stick with the stock length valve, single piece, SS. It will have one groove for the keeper. BTW keepers can be purchased to allow for a slightly higher installed height. For example: 1.650 to 1.700".

As a general rule, try to keep closed valve spring pressure between 95-120 and open to slightly over 300 on flat tappet hydraulic camshafts. The greater the pressure the more wear is likely. You need to evaluate all these parts to match your cam's lift.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.

Edited by - Bill Boyle on 12 Dec 2011 07:58:13 AM
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 12 Dec 2011 :  10:06:25 AM  Show Profile  Reply with Quote
Crower 68404 valve spring
113 lbs at 1.600"
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mjs69
Two Feathers

26 Posts

Posted - 12 Dec 2011 :  2:29:01 PM  Show Profile  Reply with Quote
Thanks for the replies...

Lunati reccommends these valve springs...#73949...here are the specs on them...

Lunati Intro Series valve spring set

Spring Type: Dual w/damper
Outside Diameter: 1.440 in.
Inside Diameter: 0.750 in.
Seat Load: 120 lbs @ 1.650 in.
Open Load: 265 lbs @ 1.250 in.
Coil Bind: 0.950 in.
Spring Rate: 363 lbs/in.

The crower springs look pretty similar...the crower spring has a smaller OD...1.405 vs. the lunati's 1.440...would machining of the head spring cups be necessary to accomodate the crower spring?

The crower spring has a shorter installed height as well, 1.600 vs. 1.650....what would be the correct valve stem length to accomodate each of these? Manley recommends these valves for my heads...11355 and 11364. Both valves have a lenght of 5.100. I'm assuming both are the stock length?

Bill, what are you referring to by "keepers" ? What would be the ideal installed height for my springs? Am I going to need shims as well? If so, what do I need to take into account with them as it pertains to installed height?

Thanks all...





Edited by - mjs69 on 12 Dec 2011 2:37:02 PM
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Bill Boyle
Horse Feathers (Charter Member)

USA
5331 Posts

Posted - 12 Dec 2011 :  8:27:57 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Just some basics.

The valve spring can sit on the perch without a shim. Stock springs are done this way usually. Many stock systems were under 1.600" installed height, and the valve train was not adjustable. The studs were located at a certain height and the lash was simply adjusted by screwing down the jam nut to 20 lbs ft. With mods to the heads, and mods like good studs like ARP, you need to think differently and do things differently.

The recommended springs from Lunati suggests 1.650" installed height. Compressing the spring tighter increase the tension. Increasing the installed height decrease the tension. 1.650 will give you the approximate number referenced by them.

A stock length SS valve should work with 1.650" installed height. That height is compressed to that height when installed with no shim, or shim, spring to bottom of the retainer. A. .030" shim can be used under the spring or other incremental sizes to get the desired installed height. The keepers I refer to are valve locks which lock the retainer in place. They come in different heights and can be used to tailor the installed height. Your stock valve locks are probably fine and can be reused. New ones are not expensive so you have options.

How close do you try to get to the installed height? In my opinion, as close as possible. Springs will vary from one to the other and they are not necessarily paired exactly to provide the same numbers. You may find that one pair of inner and out springs when tested are 10 pounds too high, while other are 10 pounds less. Being a bit anal, I've had my springs tested and paired to be as close to the projected spring pressure as possible. A little overkill for a street engine, but that's me. Performance is in the details. Getting the exact 1.650" installed height is a job. You can get pretty close, but don't go nuts with it. Been there done that. I've worked and reworked spring heights so they vary little from one spring to the other--again that's me. If you are .005-.014 between them press on. If spring pressure is 100 on most springs and 103 on others--not a concern. Same applies when open. A few pounds one way or the other is nothing. A big variation--that's a problem.

What is the stock valve length for 16 or 62 heads? Not sure anymore. Someone like Steve Leary may have a few laying around his garage. Maybe he knows. What about you Steve Coombes? Got any to measure?

Bill


"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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mjs69
Two Feathers

26 Posts

Posted - 12 Dec 2011 :  10:06:10 PM  Show Profile  Reply with Quote
Thanks for the reply...a bit confused here, thanks for your paitence...

My heads are totally bare castings, so everything will need to be new...

ok, so lets assume I decide to go with the crower springs that have an installed height of 1.600. I'm planning on using comp cams magnum roller tip rockers....will this still essentally be a "non-adjustable" valvetrain similar to stock? Would it be better to go with one of the shorter valves I'm seeing or one of the longer ones?

I'm seeing valve stem lengths varying from 4.980 up to 5.230, .25 inch is a lot of variance! Most seem to be coming up between 5.08 and 5.10 when I try to narrow down applications...I also found this on another forum concerning this...

"The heads have a 1968 casting date and are head # 62. The old valves measure 2.11 x 5.095 intake and 1.77 x 5.085 exhaust."

So the 5.10's recommended by manley are in the ballpark...how much room for error do I have here?

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Steve C.
Chief PONTIAC

2082 Posts

Posted - 12 Dec 2011 :  11:15:35 PM  Show Profile  Reply with Quote
I personaly do not have any cylinder heads to measure. A quick look at some books I have suggest numbers like 5.090", 5.092" and 5.100".
But I've seen on numerious occasions it mentioned by some very knowleagable people that they like the Crower 68404 as a popular stock replacement valve spring (stock O.D., no machine work). And I believe that is in conjunction only with a 1.5 rocker ratio. Sorry, I'm certianly not much of an athority here.

Edited by - Steve C. on 12 Dec 2011 11:17:16 PM
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mjs69
Two Feathers

26 Posts

Posted - 13 Dec 2011 :  12:14:54 AM  Show Profile  Reply with Quote
thanks for the reply...

I measured the existing shim from my #62 head with a caliper/micrometer...it's 1.422 inches...so if I stay under that in outside spring diameter, I'm ok, right? I can't seem to find anything that specifies valve spring pocket clearance....on that same note, the valve "pockets" on both my heads are only recessed slightly on one side, the rest of it is just a flat round pad....

The crower spring seems to be what I'm looking for....the only problem I see with it is the installed height. The cam card for the lunati camshaft recommends an installed height of 1.650, +/- .02...I'm guessing this isn't the right spring for that?

Been doing some reading, I'm starting to get the idea that actual valve stem length isn't as big of a deal necessarily, as long as it's long enough for the recommended installed height of the spring...does that sound right?
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cortcomp
Coyote

USA
5476 Posts

Posted - 13 Dec 2011 :  10:46:31 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
On the machining note, it's only on some heads that you'll need to machine for some springs. We had a set that said they would need machining, and they fit perfectly fine on the later 6x heads *shrug*
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Bill Boyle
Horse Feathers (Charter Member)

USA
5331 Posts

Posted - 13 Dec 2011 :  11:48:56 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
mjs69--the diameter of the shim should fit the spring pocket and the valve spring must fit atop the shim. 1.440" diameter dual springs should work fine. The Crower springs should work with your slightly higher lift using 1.5 rocker ratio.

Steve C. I have a set of the Crower springs and were mounted on my 6x-4 heads. They worked fine with my .476" lift 270H Comp Cam and were set at 1.600 installed height. I used my stock valve locks too.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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mjs69
Two Feathers

26 Posts

Posted - 13 Dec 2011 :  12:47:55 PM  Show Profile  Reply with Quote
Thanks again for the replies everybody...

I found another crower spring that may work good...#68324. 1.65 install height, Dual spring, It's got a 1.385 OD, 108lb.@ 1.650, 283lb @ 1.000, and a 0.91 bind, which should be fine with my .489 lift (1.6500-.489+0.060)= 1.101, which is .19 greater than the bind...it's a touch light on the open pressure, but 283 should work ok, right?

What do you guys think about that spring?
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 13 Dec 2011 :  11:40:23 PM  Show Profile  Reply with Quote
After the valve job, and any necessary work involved during for installation, if it did in fact end up at or close to the rated 1.650" installed height, my first reactation is the theoratical 108 lbs seat pressure is margional at best to control the valves with a Voodo/Ultradyne lobe profile. Especially knowing that a valve spring can and does lose some pressure after run in.

Indications why Lunati suggested 120 lbs seat pressure. Better more than not enough.

Edited by - Steve C. on 13 Dec 2011 11:45:34 PM
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mjs69
Two Feathers

26 Posts

Posted - 14 Dec 2011 :  12:04:32 AM  Show Profile  Reply with Quote
Does 5 lbs of seat pressure make that much of a difference? 108@1.65 vs 113@1.60? And wouldn't the #68324 spring with 108 @ 1.65 have more initial resistance than the 68404 spring? It's rating at 1.65 is only 96 lbs... The 68324 is rated at 118 @ 1.600....so unless I'm totally not understanding this, the 68324 actually has more initial pressure than the 68404, it's just a longer spring with a different install height. So wouldn't that 68324 spring actually be closer to lunati's recommendations for seat pressure @ 1.65?

The other advantage I'm seeing is a bigger gap between max lift +.060 and the coil bind...the 68404 only has .10 over the bind, where the 68324 has .19....

not trying to debate, just trying to understand this...where am I looking at this wrong?

Edited by - mjs69 on 14 Dec 2011 12:07:18 AM
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 14 Dec 2011 :  11:27:57 AM  Show Profile  Reply with Quote
The subject of distance from coil bind in this thread might be of interest:
http://forums.performanceyears.com/forums/showthread.php?t=577211&highlight=coil


Edited by - Steve C. on 14 Dec 2011 11:29:11 AM
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 14 Dec 2011 :  11:43:35 AM  Show Profile  Reply with Quote
"When in doubt, run slightly more seat pressure . . . not less."
http://www.cranecams.com/faqview.php?s_id=33

There was a fellow on PY that had issues with his combination nosing over at a much lower rpm than it should have been. I don't remember the exact amount of seat pressure involved but the specific valve springs he was using were commonaly rated at 115 lbs, I believe he was close to that. Short story, upon inspection he found his pressure over time had dropped to about 95 lbs on the seat. Therefore he did not have enough seat pressure to control the valve action as it returns to the seat, or what is often refered to as valve float.
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mjs69
Two Feathers

26 Posts

Posted - 14 Dec 2011 :  1:47:56 PM  Show Profile  Reply with Quote
Thanks for the links Steve (and your paitence :) )...good reads on both...

I think I'm going to error on the side of caution and just get the recommended springs from Lunati, and have the spring pockets machined if necessary...they have a seat pressure of 120 lbs @ 1.650....the highest of the three sets we are talking about and what the cam card recommends...

Ok...having crossed that bridge for now...valve stems...been doing a lot of research, best info I can come up with is that they were somewhere between 5.08 and 5.10. So I can't go wrong with 5.10's right? Will these be long enough with the 1.65 install height?
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Bill Boyle
Horse Feathers (Charter Member)

USA
5331 Posts

Posted - 14 Dec 2011 :  4:08:24 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
You'll be fine with 5.10 length SS one piece valves.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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mjs69
Two Feathers

26 Posts

Posted - 14 Dec 2011 :  6:13:58 PM  Show Profile  Reply with Quote
Exellent, thank you both very much for your help!

One last spring question...are these stiffer springs going to fry my cam during break-in? I've heard horror stories about that...am I going to need break in springs?
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Bill Boyle
Horse Feathers (Charter Member)

USA
5331 Posts

Posted - 14 Dec 2011 :  7:59:25 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Some companies recommend breaking the new cam and lifters in with only the outer spring in place. Some don't. Fore example, Comp Cams 995 springs are bigger, heavy springs and Comp recommends this procedure. These springs exceed 300 at open lift, the Lunati's discussed are considerably less. Find out what Lunati recommends.

There is a lot of fear today because of the tales of lobe wear that I believe is related to a couple of things. Increased lift on flat tappet cams requiring great tension to keep the lifters on the lobe and the decline in ZDDP in our oil.

As mentioned too much tension wears stuff out, not enough won't do the job.

When breaking in any new flat tappet cam/lifter set be sure to lube the lobes during installation per the manufacturer's guidelines and be certain of your rocker arm adjustment before firing. Oil needs to contain plenty of ZDDP. Deep Purple comes to mind, there are others now.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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mjs69
Two Feathers

26 Posts

Posted - 14 Dec 2011 :  8:55:34 PM  Show Profile  Reply with Quote
Thanks....I've never had a cam go flat on me during breakin, but it's been 20+ years since I've rebuilt a motor...I know the oils and such are missing some of the goodies they used to have. I remember the good old days when I could build a sbc with 11.5:1 pistons and not worry about it because I could still get 102 octane leaded fuel...lol...things have changed!
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cortcomp
Coyote

USA
5476 Posts

Posted - 14 Dec 2011 :  10:11:30 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
My dad loves to talk about the good old days when you could get a SBC full rebuild kit, with pistons, for like $250.
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mjs69
Two Feathers

26 Posts

Posted - 15 Dec 2011 :  09:32:34 AM  Show Profile  Reply with Quote
yep...I remember being able to completely do a real nice 350 for under $2000...now that same amount barely covers the cost of the machine work....
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455 Formula
Cochise

USA
244 Posts

Posted - 16 Dec 2011 :  5:54:46 PM  Show Profile  Reply with Quote
For a flat-tappet street motor, I keep valve spring open pressures under 300 lbs as a rule.

I recently saw a Comp XE-274 (Pontiac) Cam/Lifter/Spring kit that provided over 340 lbs open presusre and that was with the springs installed at their recommended dimesnion. I think this is a factor in the number of Comp Cams lobe failures. Because of this trend, I only use camshafts made by Iskenderian or Ultradyne and I use only (3) different valve spring combinations:

For stock height Pontiac applications, I use the Crower #68404. On the old 389/421 heads, I lower the spring seats to 1.700" and use the Crower #68405 springs.

On my Pontiac 413, I ended up with an oddball 1.687" installed height dimension. On this engine, I wanted to keep open pressures under 280-290 lbs, so I used an Isky #5105 dual spring with damper that yields 100 lbs @ 1.687" at about 275 lbs open @ 1.687" respectively with .470"/.500" net valve lift measured at the retainer.

I have also used the Isky #5105 in Pontiac roller cam installations where the spring is installed at the Isky recommended height of 1.531" with 150 lbs seated and 335 lbs open @ .500" lift. The spring has a coil bind height of .940" and is very stable at elevated RPM's.

Edited by - 455 Formula on 16 Dec 2011 5:56:05 PM
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goatasaurus rex
Sitting Bull

160 Posts

Posted - 17 Dec 2011 :  9:22:49 PM  Show Profile  Reply with Quote
ferrea valves good quality for the $$
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mjs69
Two Feathers

26 Posts

Posted - 18 Dec 2011 :  12:01:34 PM  Show Profile  Reply with Quote
The machinist that is going to do my engine said the 1.440 lunati springs will fit just fine with no machining,,,,I'm going to use those since that is what lunati reccommends with that cam...

Thank you very much everybody for the help!
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beertracker
Cochise

442 Posts

Posted - 19 Oct 2019 :  8:28:38 PM  Show Profile  Reply with Quote
Lunati reccommends #73949 valve springs for use with their Voodoo 10510704 cam. Are these valve springs sold as single or double spring?

The cam card only lists a outer spring and no mention of inner spring.

Edited by - beertracker on 19 Oct 2019 9:41:28 PM
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beertracker
Cochise

442 Posts

Posted - 19 Oct 2019 :  9:40:16 PM  Show Profile  Reply with Quote
I answered my own question.

https://www.hotrod.com/articles/hrdp-1011-what-you-need-to-know-about-valvesprings/
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 19 Oct 2019 :  9:53:18 PM  Show Profile  Reply with Quote
Lunati 73949 are dual springs. They work good with the voodoo series cams, just have to watch the installed height. Stock length valves and stock installed height on most of the d ports run 1.55-1.58. Shoot for 130 lbs seat pressure on the aggressive cams like the voodoo and comps for a 30* intake face angle or 120lbs on a 45*. Stock springs install heights the Crower 68404 come the closest to 120-130 seat.

The lunati 73949 are the next jump of for installed height in the 1.62- 1.65 range. Usually either have to cut the spring seats or run a longer valve to get to that number. Getting rid of the spring splash guards gains a little. If I recall correctly the 6x-4 valves are slightly longer than 6x-8 head valves. Running 6x-4 ferrets in a 6x-8 might be close to running the lunati 73949 springs???

The compcams 995 spring the installed height will need to be 1.67-1.7. Small chamber valves in a bigger chamber head gets close to this number, ra 4 valves in small chamber d ports are close too the correct height too. Measure the installed height, multiply the spring rate by the difference in your installed spring pressure and the rates spring pressure and add or subtract that number to the rated seat pressure. Jay

Edited by - Corncob2061 on 19 Oct 2019 11:24:14 PM
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beertracker
Cochise

442 Posts

Posted - 20 Oct 2019 :  12:12:11 AM  Show Profile  Reply with Quote
I saw on Lunati page, https://www.lunatipower.com/dual-valve-spring-w-damper-1-440-o-d-1-096-coil-bind-363-lbs-in-spring-rate-qty-1.html the LUnati 73949 is called a "dual valve spring with damper". So the inner spring is considered a damper? So this spring is like a factory Pontiac dual valve spring? Of course installed height and spring rate may differ from the Lunati spring?

I plan to review http://www.compcams.com/valve-springs-101 again, good info.
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 20 Oct 2019 :  01:25:13 AM  Show Profile  Reply with Quote
The dampener is the flat looking coils on the inside of the outer spring. Dual springs have an outer spring, then the dampener, and on the inside of that is the inner spring. That is correct, Pontiac ran dual springs with a dampener for most application. Jay
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 20 Oct 2019 :  2:40:25 PM  Show Profile  Reply with Quote
Another interesting topic....

https://www.hotrod.com/articles/how-much-valvespring-coil-bind-clearance-is-safe/

Depending on the intended use and the spring and cam-lobe design, coil-bind safety margins can now vary from 0.015 to 0.120 inch, with tighter numbers predominating on very stiff valvetrains. Anything more than 0.150 inch may cause spring surge, which can greatly reduce the available spring load needed to close the valve.

Edit again... sorry for the repeat. I just noticed that I have already linked that info. Sorry for any confusion.


Edited by - Steve C. on 20 Oct 2019 3:16:34 PM
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Steve C.
Chief PONTIAC

2082 Posts

Posted - 20 Oct 2019 :  3:36:22 PM  Show Profile  Reply with Quote
If you go to page 166 you will see Lunati states to use their 73949 valve spring on all the Pontiac Voodoo HFT cams here:

https://www.jegs.com/VendorInfo/Lunati/images/lunati-catalog.pdf

Due note, this older material off Jegs web site. Good luck finding any current material from the Lunati web site, it sucks !

Sorry for a repeat as I might of mentioned this before. Paul Carter who posts on the PY board has used and dyno tested many Voodoo cams in a Pontiac combination. Not the same cam as intended here but regarding the Voodoo 703 & 704 cams he recommends min 130 on the seat / 330-340 lbs open pressure. This is with valves that have 30 degree seats (less with 45 degree seats). And to keep coil bind distance under .100". And I suspect he states this knowing, like all springs, they are going to lose some pressure with run in and use. Food food thought.
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beertracker
Cochise

442 Posts

Posted - 22 Oct 2019 :  12:01:28 PM  Show Profile  Reply with Quote
I suspect my heads will need a valve job so should I measure the installed height after the valve job then order springs? The issue being won't a valve job affect the installed height measurement?
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Corncob2061
Crazy Horse

USA
570 Posts

Posted - 23 Oct 2019 :  11:56:22 AM  Show Profile  Reply with Quote
quote:
Originally posted by beertracker

I suspect my heads will need a valve job so should I measure the installed height after the valve job then order springs? The issue being won't a valve job affect the installed height measurement?



Nothing wrong with waiting to get spring until you get the heads back after machine work. The valve job can add some to the height, but usually you can pick a valve spring that is close and typically add some small shims to get the final installed height needed. The valve job will not change the height much unless your going with a different length valve. A valve job might drop the valve into the valve seat another .030 or so though if it takes much to clean the seats up. Jay
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DanM
Sitting Bull

197 Posts

Posted - 11 Nov 2019 :  2:21:51 PM  Show Profile  Reply with Quote
Install hardened seats in your heads if they are not already there. During this machining work the geometries may change a little so I agree to wait until after this work is completed to select your precise springs.
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