I'm actually from a 4x4 board but was told that my tbi question could be answered here and it looks like people here know a thing or two about it.

I'm driving an 87 chevy p/u that came with a 305 tbi motor. The engine froze up some time back and we threw in a 350 that we had laying around. Now it has never seemed to run right, in fact it has been running lean, and I have come to a conclusion that when we made the swap we should have also changed either the injectors or the computer chip or maybe both. Is this true and why is it neccessary? Also what is the difference between the 305 and 350 injectors and chip? Probably pretty basic questions for this group but would appreciate help just the same.

 

Well, you could probably just up the fuel pressure. There is a tech article on it in the tech section here.

 

I'm not sure about the differences in the chips, but the 350 injectors are bigger. That would explain your lean condition. I'd swap out injectors for a 350 set for sure. If you still have problems then I'd start messing with the chips.

 

When you say bigger is that in terms of higher pressure or larger volume of fuel flow or just bigger in size?

 

Bigger as in more flow at same pressure. 305 injectors are 45pph and 350 injectors are either 55pph or 65pph based on application.

 

You should get the TBI 350 truck injectors,(AC/Delco# 17112493),350 knock sensor (AC/Delco# 10456288) and knock module (AC/Delco# 16128261).These are the parts I changed when swapping 350 in place of 305 and I have had no troubles.Adjustable fuel pressure regulator is also a very valuable tuning device....make your own or buy one from Turbo City for about $65.
-Rich-