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del409
Tribal Scout

USA
6 Posts

Posted - 08 Apr 2016 :  10:37:42 PM  Show Profile  Reply with Quote
I have a Pontiac 400 that is bored out to .40 over. I currently have a set of #16 heads dated k137 which is as I understand to be November 13 of 1967. Looking at listings #16 did not come out until 1968. Are these considered 68 heads. They are Dport heads and hope to run on my 400. What is a good cam and do I need to run 12-14 dished pistons with this combo.

Blued and Painted
Chief PONTIAC

USA
3405 Posts

Posted - 09 Apr 2016 :  1:11:22 PM  Show Profile  Reply with Quote
Two trains of thought on camshafts
Lower the compression to 9/9.5 to 1 and use a modern wizz bang camshaft with steep ramps for efficient charging of the cylinder.

Leave the compression @ 10.25 to 1 and use an older grind with long Advertised Duration to reduce cylinder pressure.

Cam wars.
-- http://psp.aquacomp.net/topic.asp?TOPIC_ID=5982 --

It takes a while for things to get heated up.





Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 09 Apr 2016 1:17:34 PM
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Phil
The Great White Buffalo

USA
7215 Posts

Posted - 13 Apr 2016 :  10:59:09 AM  Show Profile  Reply with Quote
Great heads, I am working on a 400/16 heads project as well.

I would say it depends upon your skill with tuning/dialing in the fuel and timing curves as well as the availability of decent pump gas in your area. If both are good, I wouldn't worry about the compression with those heads provided good piston choice, build quality and cam choice naturally.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Tub
Sitting Bull

172 Posts

Posted - 13 Apr 2016 :  1:03:47 PM  Show Profile  Reply with Quote
"...it depends upon...the availability of decent pump gas in your area..."

There are 2 brands of octane booster which are said to actually work. At 10:1 CR or less, it shouldn't take much of either of these products to make 91-93 octane pump gas safe.

http://www.amazon.com/Torco-Accelerator-32oz-Best-Additive/dp/B004ZO3VN0

http://www.jegs.com/i/Race-Gas/814/100032/10002/-1?parentProductId=3410293

"... #16 heads dated k137 which is as I understand to be November 13 of 1967. Looking at listings #16 did not come out until 1968. Are these considered 68 heads..."

Yes, by Nov of '67, the '68 model cars were already in production. So, all the engine parts would have been built before '68.

"...Cam wars...
It takes a while for things to get heated up.

Yeah, looks like those heated "Cam wars" have run a lot of guys off from this site. It's sad that some guys think their opinion is the only one that counts, and that anyone with less experience or a different opinion should not even offer an opinion.

"...What is a good cam and do I need to run 12-14 dished pistons with this combo."

Since you did ask "what is a good cam", I'll offer my opinion. Keep in mind, I'm not a pro engine builder, and these cams are just suggestions of cams that, in my personal opinion, MIGHT work for you. I have no quarrel with anyone who has a different opinion than mine.

Assuming you run 9.5 static compression or more, the Summit 2801 is the cheapest and smallest cam I'd recommend. And, keep in mind, I'm not recommending cams that will extract the very last bit of power from your engine. I'll leave that argument for the engine building pros.

http://www.summitracing.com/parts/sum-2801

If you have a manual trans, or a converter that will actually stall to at least 3000 rpm, the Summit 2802 might be a decent cam, for you. The 2801 looks to me to be a higher lift version of the Pontiac 068 cam, and the 2802 looks to be a higher lift version of the Pontiac 744 cam.

http://www.summitracing.com/parts/sum-2802

The biggest cams I'd recommend for a mild 400 are the Crower 60243 and the Howards 410051-14.

http://www.crower.com/camshafts/pontiac/pontiac-287-455-compu-pro-hydraulic-cam-284-hdp.html

http://www.summitracing.com/parts/hrs-410051-14/overview/make/pontiac

Crane makes one that looks similar to the 60243, but has a 114 LSA. Some say a 112 to 114 LSA will give a better idle and more low end vacuum than a 110 LSA. I don't know if that's so or not--won't argue.

http://www.summitracing.com/parts/crn-283951

A Crower 60916 should give more low end torque, vac, and a smoother idle than the 60243. It looks to fall somewhere between the 2 Summit cams I mentioned. So, if you have an auto trans and/or will do most of your driving under 5000rpm, this might be a good choice.

http://www.summitracing.com/parts/cro-60916?seid=srese1&gclid=Cj0KEQjw3Le4BRDxx5bk4aDn9t4BEiQAfmxQGU5QtfkjCVFkQkOlBkH71HaehJQj29eA_cGDc08Gr78aAhO78P8HAQ

If you don't like Rhoads lifters, the Hylift-Johnson 951R lifters are said, by many, to be the best. Paul Knippen is a Pontiac guy who sells these lifters. Some of you guys may know of other vendors.

https://www.facebook.com/PaulKnippensMuscleMotors/

Hey, these are just some ideas that might help the OP. I have no argument with anybody on this site, regardless of your cam choices.

Edited by - Tub on 13 Apr 2016 2:34:43 PM
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 18 Apr 2016 :  09:32:40 AM  Show Profile  Reply with Quote
Personal experience with a .30 over 400, zero decked, #16 heads - cc'd at 72cc's. Be careful. Without any dishing, no matter what cam you put in, you will be on the edge with detonation. It's a ballsy engine for sure, but the chances of detonation are HUGE. Perfect tuning through the entire curve, proper carb, again, good luck. With todays gas, you are far better off getting the compression down to 9.5:1. With that, you can always get gas for it.

Note on octane boosters: Most, if not all are nothing but snake oil. Take this formula for using Toluene to boost your compression (I used it for years until it got far to expensive)
Toluene = 114 octane
Premium Gas = 93 if you can get it
16 gallon tank on a GTO

12g x 93 = 1116
4g x 114 = 456
1116 + 456 = 1572
1572 / 16g = 98.25

So basically, 4 gallons of Toluene must be added to every 12 gallons on 93 octane premium to get to 98.25 octane. That gets very expensive when toluene is up to $14.00 per gallon. Most of the octane boosters that are sold have toluene as their main ingredient and come in pint sized cans. They are a joke and useless when you look at the above formula.

Again - mine had a lot of power and was a fun engine but it is a constant stress in the back of your mind worrying about detonation.

Many will jump on me here talking about how they never have issues. Ok - they are either a) lucky, b)are in perfect tune every minute, c)they have their numbers wrong. Think about it, when these engines were built, people could readily get Sunoco 108 octane just about everywhere. Gas had lead too. The formulations for gas were night and day compared to todays gas. Remember the early/mid 70's when all the older cars started running like crap because the gas was gone. Detonation was rampant and very few people could tune it out. This is factual history. Again, be careful and know what you are getting into. If it doesn't bother you - go for it. It will run hard for you for sure!

Edited by - Brian R on 18 Apr 2016 2:54:34 PM
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Tub
Sitting Bull

172 Posts

Posted - 18 Apr 2016 :  6:46:59 PM  Show Profile  Reply with Quote
"...Note on octane boosters: Most, if not all are nothing but snake oil..."

I started a thread about this on PY. Several there agreed that the Torco booster works as advertised--will raise octane above 100, if that much is needed.

Also did an online search. Lots of guys on several sites agreed that the Torco DOES work.

http://www.amazon.com/Torco-Accelerator-32oz-Best-Additive/dp/B004ZO3VN0
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 19 Apr 2016 :  09:06:04 AM  Show Profile  Reply with Quote
Tub,

That's great to hear. Sounds like somebody finally put out a product that is for real.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 19 Apr 2016 :  09:16:04 AM  Show Profile  Reply with Quote
Only issue I can see with the Torco is the mixture rate and related cost.

It takes 32 oz for every 20 gallons to raise the octane by 4 points. (93 pump = 97)
On Amazon, it's 22.75 per 32 oz can. 5 tanks of gas at 16 gallons per tank would require 4 cans of the Torco adding an extra $91.00 to the 5 fill ups. Still cheaper than Toluene, but expensive and a PIA to constantly measure and calculate.

The added power is nice, its a matter of comfort and if you want the hassle.

Question: What would you guys estimate the difference in power to be for this 400 between 10.5:1 and 9.5:1 compression? Are we talking 10 hp or 50 hp or somewhere in between? For 10 to 20 hp, I would go with the engine that I can pull into any gas station, fill it up and forget it.
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tjs44
Cochise

USA
412 Posts

Posted - 19 Apr 2016 :  09:19:32 AM  Show Profile  Reply with Quote
at that CR maybe 5% a point.400 HP would go to 380.Never feel it in your ass.Tom
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del409
Tribal Scout

USA
6 Posts

Posted - 19 Apr 2016 :  10:32:11 PM  Show Profile  Reply with Quote
HEADS IN SHOP GETTING REBUILT NOW. Should know cc's soon. 91 octane is the highest grade of pump gas. What about the Comp cam P-270H-10?
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Steve C.
Crazy Horse

1674 Posts

Posted - 20 Apr 2016 :  07:07:46 AM  Show Profile  Reply with Quote
Calculate New HP From Change In Compression Ratios. For entertainment only....

http://wallaceracing.com/hp-cr-chg.php

10.25 compression with iron heads = potential for disaster !

When you often see it reported that others are running higher compression note more often than not the use of aluminium heads. NOT apples=to=apples !

Edited by - Steve C. on 20 Apr 2016 07:11:35 AM
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del409
Tribal Scout

USA
6 Posts

Posted - 20 Apr 2016 :  8:35:35 PM  Show Profile  Reply with Quote
Heads measure at 73cc compustion chambers. Should I have the block decked? Pistons are down in hole .20". Heads are #16 2.11 and 1.77 using chevy stud and nut to be able to adjust. I think it would better to have decked just to be safe.
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Brian R
Crazy Horse

USA
1672 Posts

Posted - 22 Apr 2016 :  08:48:01 AM  Show Profile  Reply with Quote
Deck it for sure.

Consider dishing the pistons too. Get rid of all sharp edges in the chamber if there are any. Anything you can do to eliminate hot spots helps with detonation.

Edited by - Brian R on 22 Apr 2016 08:49:09 AM
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Phil
The Great White Buffalo

USA
7215 Posts

Posted - 22 Apr 2016 :  1:50:08 PM  Show Profile  Reply with Quote
Now with E-15 looming on some and already on the rest of us, I am also contemplating dishing slightly if I use the 16's. However, I am now leaning toward using the 16's on a notched 350 (street torque-highway gears) application and going with the Edelbrocks on the 400. Now I just have to decide between the 72cc CNC round ports or the 72cc D-ports on the 400, but no dished pistons in either case.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Blued and Painted
Chief PONTIAC

USA
3405 Posts

Posted - 25 Apr 2016 :  12:33:54 PM  Show Profile  Reply with Quote
I would square the decks removing around .010".. You never know where the next set of rod's and pistons will come to rest.

Rounding off the sharp edges in side the chamber can increase volume by 2 or 3 cc's.
Using a head gasket, mark/scribe, the sealing surface of the head. Keep your grinder away from the sealing edge.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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