Will any year 350 bolt up in an 86 custom cruiser. If so does cooling system and all need to swapped over also.

 

A 350 Olds motor is externally identical to the 307 and will bolt right into place. Transfer the water pump, accessory brackets, and pulleys from the 307 to the 350 to keep everything in alignment. The 307 manifolds will bolt to the 350 but your 1986 will have the crappy tubular manifolds that will restrict the 350. I'd suggest using the cast iron manifolds from the 1980-84 307s. Also the 200-4R will be marginal behind the 350, especially in a heavy car like the Custom Cruiser. And the computer-controlled carb and distributor from the 307 will work in the 350 but are not your best choice without recalibration to the PROM in the ECU.