MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

[passnbyu]

Hi All, I have a 1977 Wellcraft Airslot 21ft boat. It has a MerCruiser Alpha One 4.3 liter V6 engine in it. I'm pretty sure its not the orginal engine. I don't think 4.3 v6's where made in 1977.
Anyway, I have a rebuilt 4.3 liter long block (block, crank, heads) engine out of a 1995 Chevy Astro van. Can I interchange the block with the marine engine? Will all the part bolt to it. A 4.3 v6 is nothing more than a 350 v8 that two cylinders were cut off of. Same bore and stroke. I think a 350 v8 marine engines turns a differant direction than a auto 350v8. One spins clockwise the other counter clockwise. Does the Marine 4.3 spin the same way as the auto engine? Would anything be different?
Thanks for letting me ask my question an any answers that you have. I plan on looking though the forum for other ideas too.
Thanks to everyone! Passnbyu

 

[Don S]

Re: MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

The parts will all bolt up if you have the same vintage engine as what was in the boat. You will have problems if your new engine is newer than your old.
The engine turns counter clockwise looking at the flywheel.

 

[zbnutcase]

Re: MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

4.3s did not come out until 1985, somebody did put that in there. Standard rotation is looking at the FLYWHEEL end of the engine flywheel rotating counter-clockwise, which most all marine (and auto) 4.3s are. And depending on the year of the engine in the boat, most all external bolt ons will fit the 95 block

 

[Bondo]

Re: MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

Ayuh,... There were Alota changes to the 4.3ls over the years,...
If your new block is the same vintage as the old block,...
No problem...
if the vintages are different, there'll be All kinds of problems....

99% of our motors are standard lefthand rotational motors...

 

[passnbyu]

Re: MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

Hi, Thanks for the info. That helps a lot. One more question though. Will I need to keep the cam from the marine engine to put in the auto block. I'm thinking they may have different cam do to marine engines are all about torque.
Thanks again for all the good info!!

Passnbyu

 

[Bondo]

Re: MerCruiser Alpha One 4.3 liter Engine interchange, which direction does it spin

Will I need to keep the cam from the marine engine to put in the auto block.

Ayuh,... Find a Truck motor, 'n you can run it As Is...
That van motor should be just Fine...

A Truck/ RV/ Marine cam is what yer lookin' for...