l30 to l31 swap

[Michaelk79]

Hello I've swapped an L31 into my 98 Chevy that had a L30 in it and now it feels like it has less power,has crappy throttle response and has trouble climbing hills now and feels like its cutting out when I push it up to speed. But every thing that was on the 305 is now on the 350 what all do I need to change to get this thing running better.

 

[96C1500]

Did you use the 305 computer? It might learn the 350 if you drive it around, otherwise you might need a tune. The TB might be different, idk

Sent from my Vortec powered Stratosphere

 

[Big D]

im gonna say a tune is a must for that swap

http://performance.com/services.asp

there the most popular and everyone seems to be happy with them.

 

[Michaelk79]

Throttle bodies are the same I'm wondering about O2 censors,MAF and such.

 

[inthechateau]

You need to have the PCM tuned for the 5.7. It is not getting enough fuel at the correct proportions. Different O2 setup, different air/fuel mix, air inlet. Would not think it makes that big a difference but you are experiencing that difference. Did you upgrade the injector unit at time of swap? Old poppet valves may be giving you a hose too. Let that thing breathe and it will run like a rapped ape.