Having to put a v8 fuel tank in a stock v6 truck

[Willy97chevy]

Okay so I'm updating my status which it doesn't seem okay with talking to anyone but my problem is this, I did the v6 to v8 swap and now it seems I've lost all hope for my vortec v8 to be right. I tested the v6 fuel pump and it is still pushing gas to the v8 until yesterday I put a gauge on fuel rail and only getting enuf gas to start it. I'm really just gonna say how hard is it gonna be to take out the v6 fuel tank and put a v8 tank back under it? Wiring is totally different

 

[Nad_Yvalhosert]

There are 2 tanks for the pickup trucks. 25 and 34 gallon. I looked on Rockauto. The 25 gallon for the V6 and the V8 are the same part numbers. The 34 gallon for the V6 and the V8 are the same part numbers. So there's no such thing as a V6 tank or a V8 tank.

The 4.3 Vortec fuel pressure spec is the same as the 5.0 Vortec and the 5.7 Vortec. I looked on Rockauto. They're the same part numbers, so there's no such thing as a V6 pump or a V8 pump.

Fuel volume and fuel pressure are very different. A bad Vortec pump can make 50 psi, send plenty of flow to the engine and still not start the engine...

Lastly the original fuel pump wiring connector was a 4-flat style. There was a update design to the sending unit in later years. It was a 2x2 square plug. Perhaps that's your "totally different wiring".

Vortec spec is 60-66 psi. If you dont have that, replace the pump. If the sending unit is bad/rusty, replace it too.

 

[df2x4]

Can you give us some more info about your swap? What year is the truck? What year is the donor V8 from? Did you transfer or modify harnesses, etc.?

There's a bunch of smart folks here, the more info you give the more likely they are to be able to help.

Here's a link to the '88-'95 (and '98) GM factory service manuals, those may be helpful. Good luck, hope you get it figured out.

https://www.gmt400.com/threads/88-95-service-manuals.43575/