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 Too much cam? Crower 60919
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74GP455
Tribal Scout

USA
3 Posts

Posted - 30 Jun 2016 :  09:41:39 AM  Show Profile  Reply with Quote
Hi all, my first post here and seeking some help. Here's what I have:

1974 Grand Prix, 3.08 posi, TH400 w/ shift kit and Neal chance 11" converter (2000-2800)
'76 455 bored .30 over, orig crank .10 under. Speed pro forged Pistons, orig rods prepped, arp bolts.
1974 4X heads, completely refurb, all new valves, guides, no port work.
Harland sharp 1.5 roller rocker arms, edelbrock performer intake, Holley 750 vac secondaries.
Ram air exhaust manifolds, 2.5 exhaust with crossover.

I called crower and gave them what I have. I said its going to be a weekend use, I may take to the track for some fun too. I wanted it to be snoty, but I don't want to give up low end torque because of the weight of the car (4200). I was orig thinking the 60916, but he talked me into the 60919:
304/321 adv dur, 231/240 @.05, 470/470 lift and 112 lobe sep.

Been doing a lot of reading since then, and my concerns are am I going to lose low end torque? Will I have enough vacuum, would a set of rhoads lifters and 1.65 rockets help? Or should I just exchange the cam for something else?
The machine shop who did the heads said that if I went above .475 lif he would recommend a different set of springs, so I have that to consider as well.
Thank you all in advance....Ray

tjs44
Cochise

USA
411 Posts

Posted - 30 Jun 2016 :  10:11:51 AM  Show Profile  Reply with Quote
will be fine in a 455.Tom
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74GP455
Tribal Scout

USA
3 Posts

Posted - 30 Jun 2016 :  10:14:03 AM  Show Profile  Reply with Quote
Oh yeah, they are the 98 cc 4x heads..
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 30 Jun 2016 :  1:05:28 PM  Show Profile  Reply with Quote
I agree.

The 60916 would be a little too mild IMHO for this application. Welcome to PSP!!

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 - 30 Jun 2016 :  8:44:07 PM  Show Profile  Reply with Quote
"...my concerns are am I going to lose low end torque? Will I have enough vacuum, would a set of rhoads lifters and 1.65 rockets help? Or should I just exchange the cam for something else?
The machine shop who did the heads said that if I went above .475 lif he would recommend a different set of springs, so I have that to consider as well."


Sounds like the Rhoads lifters, and 1.5 rockers might give you everything you want.

Also, the Melling SPC-8 cam is very similar and cheaper.

http://www.ebay.com/itm/Engine-Camshaft-Stock-MELLING-SPC-8-fits-68-70-Pontiac-Firebird-6-6L-V8-/131527250214?hash=item1e9fa29126:g:~WEAAOSw-vlVjneN&vxp=mtr

But, if you don't like the ticking sound of the Rhoads lifters, you could buy Howards version of the 041 cam. It has much less adv duration, but about the same @ .050 lift. Also has a 114 LSA. Should make plenty of vac and low end torque.

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

Most guys recommend the 68404-16 Crower springs.

https://www.summitracing.com/parts/cro-68404-16

And, lots of guys recommend the Hy-Lift Johnson 951R lifters. Same brand that Rhoads modifies for their bleed down lifters. Paul Knippen is one Pontiac guy who sells the Hy-Lift Johnson lifters.

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

Their standard lifters are sold on Ebay.

http://www.ebay.com/itm/Pontiac-H-951-Hydraulic-Lifters-The-true-Pontiac-replacement-Johnson-Lifters-/161898190053?hash=item25b1e254e5:g:kewAAOSw9eVXWWlE&vxp=mtr

http://www.ebay.com/itm/PONTIAC-HYDRAULIC-FLAT-TAPPET-LIFTERS-326-350-370-389-400-421-428-455-HO-RAM-AIR-/380622087808?hash=item589ed82680:g:efMAAOxyJs5RbEfW&vxp=mtr

Edited by - Tub on 30 Jun 2016 9:26:56 PM
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Lee
Sitting Bull

101 Posts

Posted - 30 Jun 2016 :  10:59:25 PM  Show Profile  Visit Lee's Homepage  Reply with Quote
I ran a rather similar cam, an UltraDyne 288/296 (231/239, 108LSA) in my old Firebird. I had ported 16 D-ports, dished pistons, and just under 10.0:1 compression.

When I got it, it ran lower 12's with 3.31 gears and a stock converter. It eventually blew up both that rear end and the torque converter.

Hughes 2500 and 3.42 gears it ran 11.7's

Later, with a custom Hughes converter that flashed to around 3500, it ran 11.5's.

IMHO, with unported heads, that is too much cam. As the intake duration increases, you trade low-end for top-end. If you don't have ported heads, you are NOT going to gain any significant top-end.

A GREAT cam for you would be an UltraDyne 280/288. That is a 223/231. For your application, get it ground on a 112. Contact Bullet Cams, and they should be able to have it ground and shipped to you rather quickly.

CURRENT: '73 T/A clone, boring at the moment...
67 Firebird (sold) 11.27 @ 119.6 Feb. '05 issue HPP
69 Falcon wagon, 10.51 @ 130mph Feb. '10 issue PHR (sold)
72 Cutlass Convertible, first car, owned since '82, now with a 6.0 LS, mild, putting just under 400 hp/tq to the wheels.
www.LNLPD.com
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Steve C.
Crazy Horse

1672 Posts

Posted - 01 Jul 2016 :  07:32:24 AM  Show Profile  Reply with Quote
I just had Bullet do a custom cam it took a little over a week.

http://www.bulletcams.com/Masters/ultradynemasters.html
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loosetappet
Sitting Bull

113 Posts

Posted - 11 Jul 2016 :  6:40:20 PM  Show Profile  Reply with Quote
quote:
Originally posted by Lee

I ran a rather similar cam, an UltraDyne 288/296 (231/239, 108LSA) in my old Firebird. I had ported 16 D-ports, dished pistons, and just under 10.0:1 compression.

When I got it, it ran lower 12's with 3.31 gears and a stock converter. It eventually blew up both that rear end and the torque converter.

Hughes 2500 and 3.42 gears it ran 11.7's

Later, with a custom Hughes converter that flashed to around 3500, it ran 11.5's.

IMHO, with unported heads, that is too much cam. As the intake duration increases, you trade low-end for top-end. If you don't have ported heads, you are NOT going to gain any significant top-end.

A GREAT cam for you would be an UltraDyne 280/288. That is a 223/231. For your application, get it ground on a 112. Contact Bullet Cams, and they should be able to have it ground and shipped to you rather quickly.



Lunati has a grind similar to that Ultradyne 280/288, but on a 110 LSA. Number is 10510313. I was considering this grind for my 406. If it works good in a 455, will it be too much cam for a 400/4spd car?
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