Volvo Penta engine swap

[Rich Richer]

I bought a 1997 Sea Arrow with the 4.3 liter V6 gm block and single prop outdrive. The engine may need replacement. I've located a 5.7 liter V8 that was rebuilt and in good condition. Assuming the engine bay is big enough, will this be a bolt up exchange or am I getting in over my head with mismatched everything?

 

[sandkicker]

Will need to change the drive itself as well... 6 cylinder engines and 8 cylinder engines use different reduction ratios. The ratio is controlled by the gears in the lower 1/3 of the drive. You may be able to just swap the lower third if you can find the correct ratio The engine should be a bolt up.

 

[o2batsea]

There is no reason why you can't drop in the 5.7. As mentioned, the v6 uses a different gear set. You may be able to "prop" yourself into a fairly comfortable RPM range by going up in pitch. It's been done lots of times. Now, you would certainly be better off if you had the matching drive gears for the bigger engine. The thing is, with the pitchier prop, you will lose hole shot/acceleration. Perhaps maddeningly so.

 

[jimn]

I bought a 1997 Sea Arrow with the 4.3 liter V6 gm block and single prop outdrive. The engine may need replacement. I've located a 5.7 liter V8 that was rebuilt and in good condition. Assuming the engine bay is big enough, will this be a bolt up exchange or am I getting in over my head with mismatched everything?

Rebuilding the OEM engine or replacing with the same is much easier WRT attaching all of the accessories.

Why might the 4.3L need to be replaced?