# 428 cam help



## blainetigner (May 13, 2017)

Hello,
I'm Looking for recommendations for a cam, 
1969 Firebird, 4:10 gears looking to change to 3:55
1968 428cid,
Turbo 400, shift kit, 2400 HoleShot B&M converter

1969 #48 Ram Air III heads, appear to be stock. 
from what I can tell the cam CWC 641 is stock lift height "calipers" measured around .400 
and I can't find any information on the cam. but it is cast 540 / 233 and on one end 641 is stamped

I would like to keep the stock valve springs, and push rods. rockers are 1.5 stock. 

Just looking for a mild loppy cam, nothing to radical, I just want to hear it. 

I was thinking of the 041 ram air IV but not sure with this setup. 

Currently the motor is torn down, i just honed cylinders and will buy forged pistons monday...

Thanks for any help.


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## Pinion head (Jan 3, 2015)

Before settling on a cam, i would have several of the chambers on the 48 casting heads cc'ed to see what actual chamber sizes are. Original '67-69 428's had a cast piston with a near 14 cc dish/set of 4 eyebrow relief pistons. This extra, near 7cc of relief in those factory 428 pistons was to help drop static C/R to near a true 10-1 CR (factory ADVERTISED 10.5- 10.75-1). IF you have an .030 or .040 overbore 428 with 70 cc (or often less) chamber size 48's, really got to be careful with the custom piston choice in a street engine build. A mid 20's to high 20's cc dish is going to be needed to get the 428's static CR to drop somewhere into the mid 9.0's. Quite a bit of concern needs to be taken, if even a mix of 91 octane pump gas & race gas is going to be the norm.


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## bigD (Jul 21, 2016)

...I would like to keep the stock valve springs...


Looks like a '69 Bird with #48 heads & auto trans came with an 067 cam.

http://www.wallaceracing.com/enginesearch4.htm

I'd say an 068 clone is about the biggest cam that MIGHT be safe with original stock springs. I had a 744 cam in my '69 RA3 GTO. But, I've been told that cam required more spring pressure than the 068 required.

Engine Camshaft-Stock MELLING SPC-7 fits 63-66 Pontiac Catalina 6.9L-V8 | eBay 

But, if you go with new, stronger springs, that opens up a lot of cam options. 

As mentioned, you'll need pistons with a fairly large dish, in order to reduce CR enuff for pump gas. Custom is the only way to go. I assume that The Auto/Tec brand is the cheapest good quality custom out there. Ross is one of the highest. 

This guy has the best price I know of for Auto-Tec shelf & custom pistons. 

https://shanonsengineering.com/products/auto-tec-small-block-pontiac-400-428-455-flat-top-pistons

If you go with new springs, here are some decent cams, in the 220°-231° @ .050 lift range. There are obviously other choices within this range. And there are lots of custom grinds available. 

Lunati 10510312

Street Master Hydraulic Flat Tappet Cam - Pontiac V8 276/286 - Lunati Power

Summit 2802 is the cheapest of the decent choices.

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

Crower 60243 is the highest priced. 

https://www.summitracing.com/parts/...IKFZulDt2A9pAZWLhUh-eEj8rYv0UOvqfkaAnpj8P8HAQ

The Howards 410051-14 should make a nice 428 cam.

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

If you don't mind the "tick" of Rhoads lifters, an 041 clone is not a bad 428 cam. 

Engine Camshaft-Stock MELLING SPC-8 fits 68-70 Pontiac Firebird 6.6L-V8 | eBay

https://www.summitracing.com/parts/rhl-9518l/overview/make/pontiac

If you go with regular type lifters, Crower sells their Cam Saver lifters. 

https://www.summitracing.com/parts/...MEtZZjix3Dt4oV1iD8e6YTC2QGDJ_3vDNAaAl5e8P8HAQ

If you buy pistons with a big enuff dish to get the CR down to 9:1 or lower, you could choose a Voodoo 262 cam. 

Voodoo Hydraulic Flat Tappet Cam - Pontiac V8 262/268 - Lunati Power

Another option would be to go with heads which have bigger chambers. The '70 model #64 heads come to mind. Then there are the '71 model #96 heads. Or you can go with the later model 6X heads, if you don't prefer to stay with the older stuff.


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