My 91 chevy

hey yall. me and my father have been trying to get my truck up and running for a while and we found a guy who is selling a v8 that my dad wants to put in the truck. I came to ask what all I would need to replace my 91’s v6 with said v8

Well......that all depends.
Putting a Hemi or a Duramax in there will certainly be a lot more difficult, but can be done. Lol.

In a seriousness, WHAT V8 are you planning to put in there?
What year is the donor motor?
Where is it coming out of?
What transmission are you running/planning to run?

The more info you give, the more you will get.

But for poops and giggles, I'm going to assume it's another 88-94 TBI motor and 700r4/4L60 trans.

Motor mounts, exhaust manifolds or headers. Some tweaks to or an all new exhaust. Bigger radiator. But most importantly, the right ECM and chip for the donor motor.

If it's anything other than that, up gotta give more information. Then we can send you down the right path
Sounds like a fun project, post some pics of what you are working with.

Welcome to the forum from Oregon. It must be a nice truck to want to spend all the time, effort and money to do that kind of swap. Like @Drunkcanuk said, not all V8's are the same, so we need more info to help.

And you need to review about twenty pages of posts in three or more threads started by DeCaff2007 about his V8-into-a-V6-truck.