Motor swap bb to small block
 

Please has anyone ever swap out two Big Block motors for two small block motors ,i am thinking of weight, cost of new motors, fuel efficiency, and room I need in the bilge the boat is a 1995 31 sonic, i don't need insane speed anymore just cruising. some small block motors 330HP right from GM brand New please tell me your thoughts thanks

A 30' Sonic won the 1988 APBA A Class championship with a pair of relatively low horsepower small blocks ( 320 efi's with f/I swapped out for carbs.) Boat had full cabin , not gutted.

just don't want buy two new Big Block engines (502) and some stainless marine manifolds it is a bit pricey for me. but a have two new GM 350 marine 330HP small block's. some people say it will work fine, boat should do 65 mph (I would be happy) just don't want to go through all this and be disappointed

i dont see why it wont work. the engine mounts should be in the same spot on the stringers. people go from small block to big block all the time. it will bolt up i just dont know about the performance of the hull with the weight change.

Weight...weight isnt always a bad thing, also consider the fact that lightening the back will effect the center of gravity.

Fuel efficiency /performance/longevity.... A bbc has more torque than an sbc, so you will be pushing the sbc where the bbc would be happily lumbering along. So if the sbc is being taxed harder than the bbc...guess which will live longer

Space...thats a definite plus on the sbc side

All that said, 27 magnum routinely came with things like sbf's and volvos... So I think you would be more than happy with a pair of stout sbc's

383 strokers w blowers - (stirrin th pot)