Hello 3rd Gen,
I have a customer with a 91 Camaro 305TPI 5spd. Engine has a rod knock. Customer would like to replace the short block with a 400 and retain the 305 heads and TPI.

Looking for input on what modifications to the fuel injection/PCM will be necessary. Compression will be low and Camshaft will be chosen to retain stock idle and running characteristics. Just adding cubes for a little more power and torque.

If this swap will be too involved we will probably just repair the original short block.

Thanks, Matt

 

Might read the stickies tuning guide for $8d. He might consider how restrictive the tpi and heads are on a 400.
holley hsr might be a better intake choice. Don’t cheap out on injector quality otherwise tuning might not be good.

 

Thank you. Regarding heads/intake, He is not looking for ultimate performance. The cost to recondition a 305 short block or a 400 will be similar so the thought process was why not add some cubes.

 

Won't the LB9 heads raise compression ?

 

At a minimum you'll need to recalibrate for the cubic inches.

If you go with Delphi injectors, that's the closest to stock and would only really need to change the injector constant in the chip.

Probably will also need to adjust fuel and spark tables.