Set up

305 turbo 400 308 gear .I bought this way no much liking it any sugeestions 1981 silverado

 

That a wearied combo 400TH would be with a 454 or 350 with the gear being a little higher 342 or 355, 373.
305 with 350TH that 308 gear would not be to bad.
Or 305 with 700R4 a gear of 342.
There just a few but it depends on what you want or you use the truck for most of the time.