gm 305 to 350 swap

[sparky71]

Hello all,
started my boat yesterday and there was a horrible knock coming from flywheel area of motor.Removed rive noise still there so out it has to come.The boat is a 23' cabin cruiser pretty heavy and I feel under powered.
I've got a donated 350 out of a 89 1 ton van 4 bolt main with a one piece rear main seal.My questions are?
1.will this be a pretty direct swap?
2.will I be able to use my starter from the 305?
Thanks for your time any info greatly appreciated.
Dan

 

[gbeltran]

Re: gm 305 to 350 swap

If you are talking about the boat in your signature, 1983, then no it will not be a direct swap. You will need a different flywheel and coupler for the one piece rear main engine, the starter would work if you get the same diameter flywheel for the 350. The intake manifold might be different if you were going to swap that, in the late 80's several of the GM small blocks had the center two bolts on each side of the intake at a different angle than the end bolts, but you could drill your 305 manifold and make it work. If there are any brackets that bolt to the heads the 89 engine might have some of the holes in different places or no holes at all.