Then a 3″ pipe back to the muffler will dramatically help that little 170hp 305 get another 15hp and its mandatory for any decent engine upgrade.Įxhaust is the most important change for these cars. You can get them for about $50 on ebay just search for THUNDERBOLT 3 CATALYTIC and you should fine one. Then have 3″ pipe bent around to a matching 3″ cat if you need one. I recommend getting a flowmaster Y250300 collector from favorite vendor and cut it down pretty short and where the NASTY T looking y section of the factory y pipe is have that cut and new pipes bent to connect to that flowmaster y. Well honestly the exhaust manifolds are fine up to 250hp builds but the Y pipe is TERRIBLE and the single 2.5″ exhaust is too small. Change the WHOLE thing from the engine back. So start with a vortec 350 and not a TBI 350 is my main words of wisdom.ġ.

If you need assistance finding one, do a search on or check out the great deals on new GM 元1 vortec 350 engines listed on the recommended engines tab. The cost for those extra 45 cubic inches isn’t very much and worth every penny. Pickup a used 350 preferably a 1996+ vortec 350 and build on it while you drive around in the 305 and then just swap over. Also, if you want to make over 225hp, don’t mess with the 305. I tried to put these in order of importance. (exhaust, airfilter, intake, cam and heads).

there are 5 general horsepower killers on the Camaro TBI. The trucks use a flat tappet cam and if you must mess with the 305 in the trucks then there are recommended flat tappet cams on the 350 V8 modification page although the truck blocks do have all the roller cam provsions and so I would grab the roller stuff out of one of the car engines as that is 10-15 free horsepower for roller cams. Not very many 305 trucks out there but other than cam selection most of the same issues apply.

Cam for 350 tbi