I have a 89 Firebird with a 350 TPI. Pulling the heads and rebuilding the top end. Plan to up the power some. Will be getting a bigger cam in the area of .470 to .490 lift for intake and exhaust. Besides having the heads checked out for cracks and warping, and a stock rebuild with the updated springs and having a 1.6 exhaust valves cut in, any other ideas as to what should be done??? Not my first engine build up but the first Chevy based engine i am putting together. Not looking for a mega numbers motor just something hotter then stock, maybe 250 to 300 RWHP max. Thanks for all the input to come guys, read thru all the posts and did search but most say to get different heads and like i said im not looking to make a mega horse power motor. Will also be upgrading the intake system along with larger injectors, 30 lb, a EBL modded ECM, and plenum and runner upgrade mods....

Thanks
Bill

 

better cut the valve guides down for a cam with that much lift or youll have issues.

 

thanks Viper... will do these are the lil tidbits i need help with....

Bill

 

maybe get a zz4 cam works well with the stock computer and should make some decent power. along with that maybe port your heads a little if you know how/have the tools for it otherwise buy aftermarket which im guessing you dont want to do. instead of fixing you current heads you could save the money and buy a set of zz4s which will save weight increase compression ratio and flow well. o and on any head you get save yourself the trouble and either pin the stocks studs or tap for screw in studs which youd have to cut the boss down to fit or buy non-hexheaded studs.

 

yeah, get screw in studs and guide bosses cut down to handle .500 lift or so. Machine shop will know what to do. expect to pay around 100-150 bucks for screw in stud work for the pair, and another 50 or so for guide cutting/new seals.


While your at it, get a head porting kit from summit that includes cartridge rolls and carbide bits. clean up the head ports and perhaps do some bowl work. very basic clean up porting. this will give you an easy 10-20hp.

match the springs to the cam. your spring pockets will hold a 1.25 inch spring but i think you can go up to 1.27-1.29 inch springs without cutting those pockets out to fit a larger spring. if you want a mild roller cam, then most 1.25 inch springs will handle it.