Ok so ive got a new project, its a 82 z28 with the 305 crossfire. Severly lacking power. So i need to know if i can swap in something like a built 350 from a tbi silverado. Id really like to keep the crossfire injection because its unique and just looks awesome. How hard would this be?

 

CFI 305 to CFI 350 swap is easy-just use 350 cfi 'vette injecters and 'vette chip in the ECM-everything else is same between 305 and 350 CFI-i did this swap in '94.Hardest part will be the modification and porting of the CFI manifold to allow the engine to breathe at over 4000rpm-also the stock fuel pump is a major stock crossfire weakness and should be upgraded for best results.When i swapped in the stock '84 vette engine,i found it kinda lame but the manifold work and other minor tweaks made a big difference for the better including at least 1000 more usable RPM capability

 

Would it be expesive to have the manifold modified?

 

Certainly is , someone at the factory left the intake ports half full of alum.

CFI intake port on top ; reg SBC port at bottom
Get your porting gear out

 

Time learn how to save $$$ by doing it yourself.
http://www.technovelocity.com/chevyh...rt_polish.html

If you have to pay someone to work on yours then prob better to consider a different ( superior ) intake that is a bolt on

 

some have sent their crossfire manifolds off to be "exude honed";abrasives-laden paste is forced through the ports untill they are enlarged and streamlined as desired(within safe limits)i have heard this operation is expensive though.Also i feel the runner intakes should be enlarged/reshaped-i welded more aluminum onto mine for this back when i did it,but epoxy could be used if done correctly.There is also the "renegade"high performance crossfire replacement manifold (also includes lid)but avalibility of that has been spotty.Took hours and hours of die-grinder work to get mine ported to where i liked.

 

Ok so i found a few websites that actually sell stock manifolds that have been ported, for a decent price. But what about having the throttle bodies bored? I was told 454 tbi injectors would work good

 

how expensive is tbi boring?

 

the bored throttle bodies aren't needed for mild street crossfire engines-stockers are said to flow 550 CFM together,good for up around 325-350 HP-when to get into that range with a crossfire plenty of other modifications are also needed;bigger injectors,parallel plumbing,etc...