formulafastfoot

ok i dont know how to really search for this kinda stuff cause i dont know how to go aboutit and i would like someone to give me a minite of there time please ive got a 89 firebird formula 350 tpi im going to be pulling it and putting it into a 305 carbed trans am .. im turning the 350 tpi into a carbed motor and seeing as how the trans am is alsready set up for that im going to go that route so if i have a stock 350 how do i choose a cam and a carb thatll give me increase but not to much like 300 320 horses ive got headers on it now so ive got the exhaust covered but i have no idea how to choose a cam .. i guess waht im really looking for is some one to tell me what ive got and then tell me what i need ...

i have no idea what cast numbers are and how to tell if its a 4 or 2 bolt also how about pistons dished domed or what heads ive got

please some one hlep thanks you all for your time

five7kid

iTrader: (14)

Okay, let me give it a shot (and I'll try to be "gentle").

Assuming the 350 is a stock '89, the cam would have .415I/.430E lift, 207I/213E duration at .050" lift, and 117.0 degrees lobe separation angle with roller lifters and 1.5:1 rockers. It's not too bad a cam, but is pretty mild.

The heads will be 083 castings, 64cc chambers, 1.94/1.50" valves, center two intake manifold bolts at 72 degrees (vs. 90 degrees for the rest, and for all of the bolts for the typical carb intake manifold). Pretty good heads, and with basic porting ("bowl work" or "pocket porting", it's typically called) will flow very well and easily support 300 HP. You should also do something about the rocker studs, which are pressed in, such as pinning the stud to the head, or have the studs pulled out and the heads machined and tapped to accept screw-in studs. And, new valve springs should be assumed, and having the guides machined down to accept positive-type stem seals will help control oil use and provide more room for valve lift.

If you don't pull the heads, you should keep valve lift under .480". The cam you pick will also depend upon whether or not you keep the factory carb system (I did). Your goal of 300 HP is easily obtainable with a pretty mild cam, and even with the stock cam now in the engine. This is assuming you're talking about the typical HP rating, gross flywheel horsepower, and not the net flywheel horsepower the factory used to come up with 235 for that engine, or rear wheel horsepower which is often quoted these days. Just headers and a free flowing exhaust coupled with a carb induction will get that engine to 300 HP GFWHP. A Comp XR280HR cam would probably put you in the 325-350 range.

For reference, based on my Camaro's drag strip performance, using standard sea level conversion factors and horsepower calculators, I'm around 295 rear wheel horsepower and 370 gross flywheel horsepower. My heads are aftermarket replacements and fully ported, and the ZZ4 cam has slightly more exhaust lift than the Comp cam I referenced. Otherwise, it's pretty close to what you have to work with.

Sonix

iTrader: (1)

Punctuation is your friend
Your carb that's on the 305 should move over to the 350 and work well. An intake like the edelbrock performer RPM spreadbore would work well. Like five7 said, the center intake bolts are at 72* rather than 90*, kiss that with a die grinder and you're done.

izcain

If your worried about trying to pick the correct camshaft you should just give Comp cams tech line a call they are real nice on their and if you give them your idea of what your trying to do they should be able to match up a proper camshaft that will suit your needs.