[SBC-68-FIREBIRD]

Hi Guys ,

Just wanted to get a few opinions on the current cam I have in my engine. I took this engine out of my old car which was 1200 pounds heavier than the 68 Firebird I have.

The engine is a 406 with the follwing -
5.7" rods
Forged flat tops 9.85 : 1
Dart Sportsman 2's with mild porting
Performer RPM intake match ported to the heads
830 Holley
MSD dizzy
1&3/4" 4 into 1 headers , 3" collector
2&1/2" exhaust into an x pipe into Aero chambers with no tail pipes
Cam - 268 advertised duration , 238 duration at 50.
495 lift on the intake & exhaust
intake centre line 106
lobe separation 110
intake opens 28 , intake closes 60
exhaust opens 68 , exhaust closes 20

3000 RPM stall
Turbo 400
3.73 12 bolt posi
26" tall tyres

As I wrote earlier this cam was set up in a much heavier car than what I have now & I would like to see if you guys reckon it is fairly small for the rest of the combo now that I have a much lighter car ? What do you guys recommend , I would like to stick with a solid flat tappet !

 

[69X11]

First off, it's hard to reply to this since you put a chebby in a Firebird, shoud of used the Pontiac 400, but anyhow. What are you looking for out of this engine?Is this an engine that will just see street use or are you looking for a time slip? If this is just a street engine I'd say that cam is fine. If you're looking for a quick time slip, I'd shave the heads and get closer to 10-10.25:1 and go with a solid flat tappet in the 245/255 @ .050 range with around .550-.600 lift to reallt use those heads, I'd use round a 108lsa and change the rear to around 4.11-4.56 with 28" tires.JMO. If you're looking for both, maybe a solid flat cam with the same specs, but at a 110-112 lsa for a broader power range and keep your 3.73's.

 

[Z15CAM]

69X11: You mean Canadianized a 68 Firebird. Firebird's and Pontiac's came with Chevy drive trains in Canada including the Cross Ram Option. I recall a Toronto guy by the name of Terry Godsall ( if I got that right) running one on the Trans AM circuit. ))

 

[pdq67]

A 268/238 cam is quite Healthy to me!! (Unless the 3 is a typo and should be a 1 or a 2??).......

Is it from Howards and I figure it is it a solid lifter jobber, right??

Please come back and offer up some more cam info..

pdq67

PS., and in a 406 at 9.85 to 1 CR., it should be a torque monster!!!

 

[69X11]

Z15CAM, I don't believe that any Firebird ever came from the factory with a Chevy engine untill the mid to late 70's cars (even in Canada). Now some Chevy models were changed up a little in appearance and rebadged and sold thru Pontiac in Canada though, like the Acadian's. As far as the Trans Am series, those cars ran 302 Chevy engines since Pontiac didn't have any engine small enought to meet the 5 litre displacement rule. Since the Firebird was a GM product and shared a platform with the Camaro, SCCA let them transplant the SBC into those cars for competition purposes. Then in 1969 Pontiac came out with it's short deck 303 for these race cars, although none of these engines ever went into production cars either.
As for the original question, more information is needed, like primary use, power brakes?, are you worried about mileage, idle manners, etc....

 

[DOUG G]

406 ,9.5:1,280/230 (.486 I/E) stock home ported heads went 13.5 @ 101.7 with 2.73's and 13.2 @ 103 spinning with 3.73's

406,10.2:1,same cam,200cc Protoplines box stock went 12.3 @ 110

The only thing I did was upgrade heads.

I think with a street/strip car the cam is "fair".

 

[SBC-68-FIREBIRD]

The cam that I have is a solid flat tappet from a place over here ( Australia ) called Camtech !

The car will be 95% street but occasionally head out to the track but I would still like to get the most out of the rest of the combo. I believe that the cam could be a little bigger as it was set up in my previous car which was a 67 Pontiac Parisienne with a 2200 stall & 3.55 open centre which weighed 4400 pounds & was able to pull 13.4 @ 104mph. This Firebird should be at least 1000 pounds lighter with 3.73 posi & 3000 stall but everything else the same. The car does need to be able to run the power brakes , idle at the moment is very smooth but a lumpy idle would be nice , economy is not really an issue as it is not an everyday car.

I do not believe that any 60's Firebirds came out with Chevy's in them from the factory. True some of the canadian full sized cars did which is what my previous car had. When my Firebird came in from the US it had no motor or transmission but had been set up for a Chevrolet. Regardless if the car had an engine or not it was getting a Chevy put in it as I have always been a Chevy man & fitting a Pontiac engine was never an option for me.

There are some pictures of the car here -
http://camaro-firebird.dyndns.org/viewtopic.php?t=1064&postdays=0&postorder=asc&start=90

 

[sweetblue69]

69X11: You mean Canadianized a 68 Firebird. Firebird's and Pontiac's came with Chevy drive trains in Canada including the Cross Ram Option. I recall a Toronto guy by the name of Terry Godsall ( if I got that right) running one on the Trans AM circuit. ))

Untrue. I know of several Firebirds that have Pontiac engines in them, made for GM Canada.

As for the engine, those iron heads are restrictive compared to a lot of aluminum ones. The camshaft has plenty of lift, I say get a pair of AFR 195's if you have the money. That will really wake up the engine. Make sure your sitting above 10:1 CR.

I'm running a milder cam (DEH275), .460/.488 lift and the 195's make a good deal more power than sportman 2's.