ive got an 89 Lo3 TBI and i am considering a new cam and have a few ?s that im sure wil be awsered by more knowledgable persons than i 1st ? roller or flat tappet and if i go flat tappet will my old pushrods still work 2nd ? will a .480 cam work with stock valve springs on the L03 head ? i do plan to pull the heads as well and clean them up with a bench top port and polish new guides and seals maybe screw in studs and guide plates with 1.5 roller rockers car has 130xxx so head gaskets wont hurt it anyway car has tbi mods and im running midlength headers as of now and plan on keeping them how big can i go (cam) before the computer starts to become an issue any suggestions as to what cam i should go with? the car does not get driven more than about 200 miles a month so mpg is not really so important i just want to squeeze out what i can from this little 305 it runs pretty good as is for what it is id like to get 250hp out of it will this require a computer tune or can i just cam it and be done thanks in advance

 

1. Stick with roller tappets. You'll have to change push rods and timing set if you switch to flat-tappet setup, and take the risk of a wipe-out. Not worth the downgrade.
2. No aftermarket cam will work with stock valve springs. Stock valve springs aren't even enough for stock cams, let alone anything beyond that. .480" is close to the limit for stock-sized springs and requires reasonable care in setup.
3. 250 HP is not realistic with the TBI heads. No cam will fix that; doesn't matter how far you open the valve, once you get past the point where the valve is "the" restriction. Since the "swirl" "ramp" eventually becomes "the" restriction, any lift above about .450" doesn't produce any further flow. (which is NOT the same as saying, that should be your peak lift; since the valve is not even close to its peak opening for more than a VERY short portion of its cycle) Any cam that would even get close to that with appropriate heads will require tuning. For that matter, just tuning your existing setup WITHOUT changing the cam, would yied SIGNIFICANT gains.
4. A suitable cam would be the Comp "302" or "501" grinds. http://www.summitracing.com/parts/CCA-08-302-8/ http://www.summitracing.com/parts/CCA-08-501-8/

 

thanks for the info i would like to get a new chip but dont want to get ripped off and dont know what im looking for as far as which ones are real and which ones are just a joke. i have a set of 350 tbi heads from a goodwrench crate motor 30xxx miles on them if you think they would work any better ? not sure of the casting number id have to look but its an early 90's goodwrench or would this just defeat the purpose and lower my compression ratio to nothing ive read the exhaust on the 305 heads is decent for a 305 but the restriction lies in the intake any truth to this ?

 

does anybody know what cam set up will work on a 92 camaro with a 350 tpi. its a stock motor jus bored 40 over with the tpi ported.