Looking for suggestions right now i have the 305 but it's a bit sluggish it has a th400 trans I beleve what can I swap into this truck that will bolt up I beleve it has a carb but the swap will definitely be carb since I don't want to play with computers right now

 

What year truck are you talking?

I would think that the 350 (5.7L) would bolt up to the transmission and truck. Not sure if engine mounts are different, but I think they are for the most part compatible. I would do your due diligence though, and not go by my word. Not sure of the exact difference, but if it runs well, its a lot of work to gain probably 30-40 horse power (ball park guess).

 

It's a 91 k2500

 

I found a 383 stroker for cheep but not sure if I should go that way or a 350 i did a little research and the 383 will bolt up to the th400 not sure of it dropping in and bolting up to the frame I don't feel like playing with the mounts

 

So here's my issue the 305 in it runs mint no ticking nothing wrong with it as I can tell idels perfect but it takes a minute to get up to highway speeds I can floor it and it goes nowhere

 

So sounds like you've got a good engine - just under powered for the truck its in. I've got the same engine, but with the Vortec injection setup (1996) which adds some HP, and it does fine - but that is an extended cab, short bed, C1500. For a 4WD K2500, I can picture it being on the low side, especially with a carburator.

I am sure there are things that can be done to tune the engine to get a few more HP out of it, but beyond that, a bigger engine would be the answer.

From what I can see online, there was a 5.7L (350) offered for the C/K 1500 that year that only put out 210 HP. The 5.0L (305) put out 175HP. BUT the 5.7L offered for the 2500 and 3500 put out 255HP for some reason (tuned differently I suppose).

There was a 1991 6.2L diesel that only put out 150HP, but I am sure had a lot more torque than the gasoline engines. And there was a 7.4L gas engine that put out 290HP.

Good luck making a decision. I would have to think that the engine mounts would need replacing if you go beyond the 5.7L, but that is just a guess. Might even need replacing with that change. I just don't know.