Ok guys, here's what I got:

Tonight I finished my TPI swap in my v6 firebird, it now houses a 350 from a '91 Z28 camaro. I turned the key, and it started on the first try (yay!). My question is this: I never changed the fuel pump from the v6 engine. The v6 pump is supplying fuel to the 350, and I understand that the v6 pump should be replaced, however I don't have the time or funds to do this for another week or so. What can I expect to see from this fuel pump? rough idle? stalling? nothing at all? any info would be appreciated, thanks.

 

Got a fuel pressure guage? Hook it to the fuel rail and see what the pressure is, should be between 36 & 45 psi at idle. If it is considerably less than that, I wouldn't even try to drive the car. If it can't supply the correct pressure at idle then it will really have trouble at part throttle and you could do damage to several things, the injectors from the ECM tryng to pulse them longer to get more fuel (burn em up) and even worse, if it can't get enough fuel it will run lean and possibly severely damage the engine (pistons..etc.).

 

Hmm... I never even thought about it running lean like that... good point. I'll have to put the gauge on it and check it out... on the v6 it pumped out around 42 psi, but I don't know if the extra cylinders will stretch that thin or not. Thanks though.

 

and if it does supply correct fuel pressure at idle, think it would be OK to drive for a week? I know I shouldn't, but I'm kind of hurting for a car right now, otherwise I'd wait until I got the new pump.

 

As long as you don't go romping on it you could probably get away with driving it, but i'd be careful and listen for any knocking and hesitation that might be from lean running and keep a close eye on temp.

 

Ok, well I drove it home today. The temp seemed to be OK, didn't go over or anything. However, I did notice some hesitation and serious lack of power here. I'll just make do without it until I can get the new pump, I don't want to do any damage. It Idled fine for a while, then idled like it was starved, then Idled fine again, so I'm thinkin that the pump really wasn't meant to supply a V8.