302 is ford, right?
The GM 305 has dimensions very close to that of a 350, so close you can't tell which engine it is by looking at it.
One possibility if you want a smaller engine would be to trade your 350 for a 262. Swaping the 262 in an S-10 for a 350 is a very common project, so you may be able to find someone who needs a 350 and has a 262 to get rid of. The 262 is basically just a 350 with two less cylinders. The bore and stroke are the same, and they even use the same pistons. The bolt holes on the outside should also be the same if both are the same year. They still have tons of power, much more than your could use in 1st or 2nd gear in such a light car. I had an S-10 with the non-vortec 4.3L and it would spin the tires through first and part of second and chirp them going into third.