Replace OEM 305 with Reman 350

[isd503]

I replaced the original 305 in the 96 GMC Sierra with a reman 350. I have been experiencing a lack of power. The engine does not feel like it has the power of a 350.

I took it to a mechanic who drove it and noticed this too. He thinks the truck might need a software update. Is there such an update for a 96 and where would you go to get it? Has anyone ever had this issue before? How did you resolve it?

 

[Drunkcanuk]

Your computer is expecting to be running a 305, so that's what its trying to do.
It doesn't need an "update" it needs to be reprogrammed to run a 350.

Look up Black Bear tunes. It's what they do.

 

[isd503]

Anyone got any experience re-programming (tuning) the PCM with this same engine swap?

Is there a noticeable difference in the performance of the engine/transmission after the 'tune'?

 

[Stumpy]

As suggested above, hit up Black Bear Performance.

I swapped from manual to auto transmission, used the PCM from the auto truck, with a different size engine, and Black Bear hooked me right up. Ran better, and even firmed up the shifts in the auto trans.