can i bolt on a chevy v8 350 to a 91 chevy s10 5 speed transmition?

the 350 is off a 74 chevy c10 pu.

It depends on the original engine and the year of the truck. Not all five speeds were compatible.
These are the three that seem to be compatible:

Years Engine Power Torque VIN code
1986–1993 2.8 L 60° V6, TBI 125 hp (93 kW) 150 ft·lbf (203 N·m) R
1988–1995 4.3 L GM 262inch 4300cc V6, TBI 150–165 hp (112–123 kW) 230–235 ft·lbf (312–319 N·m) Z
1990–1993 2.5 L Iron Duke I4, TBI 105 hp (78 kW) 135 ft·lbf (183 N·m) A

It depends on the original engine and the year of the truck. Not all five speeds were compatible.
These are the three that seem to be compatible:

Years Engine Power Torque VIN code
1986–1993 2.8 L 60° V6, TBI 125 hp (93 kW) 150 ft·lbf (203 N·m) R
1988–1995 4.3 L GM 262inch 4300cc V6, TBI 150–165 hp (112–123 kW) 230–235 ft·lbf (312–319 N·m) Z
1990–1993 2.5 L Iron Duke I4, TBI 105 hp (78 kW) 135 ft·lbf (183 N·m) A

what was previously in the s=10? Can u measure from on bolt or bolt hole to another for dimension. If the truck had a four cyl.,,, I doubt it. If it had a v6,,,,,,,,,, maybe. More than likely ,,,,,,,, not. but if you do find a way,,,, let me know, I could use that info

i think so but only if its a 4.3 cause the 4.3 is a 350 but with 2 pistons cut. some people call it a sawed-off 350.

contact advanced adaptors for all your V-8 conversion needs.This is done all the time.Cooling seems to be a little problematic though.I used the 305 out of a Z28.Sorry no pictures(goes too fast)

If the S-10 came with a 4.3 V-6 motor then the answer is yes because a 4.3 and any V-8 made from 1955 to 1996 has the same bolt pattern as the 4.3 V-6. Essentially the 4.3 is only a 350 cubic inch motor with the front 2 cylinders cut-off of it...