I have small block 350 in my 46 with all kinds room to spare. 318 should be about same size. This truck has front clip, 350 V8 with 350 Turbo auto. and 10 bolt posi track, break booster, steering column all from 76 Camero. Was done in 1988. Currently converting to 76 power wagon frame with 440 big block and 4x4. Going from low to ground to about 30" off ground.