motor mount question 5.7 vs 7.4

[Cptkid570]

If a boat has a 7.4 mercuriser, will a 5.7 liter mercruiser bolt up to the same motor mounts or are the motor mounts in a different location for a 7.4 than 5.7?

 

[Reel Poor]

Re: motor mount question 5.7 vs 7.4

The drive is a different gear ratio and the front mount location on the stringers is slightly (a couple of inches)closer to the transom.

 

[Cptkid570]

Re: motor mount question 5.7 vs 7.4

Would the front engine mounts be the same height for both?

 

[Bondo]

Re: motor mount question 5.7 vs 7.4

Ayuh,...

I just dug out a Merc. Installation manual....

It says,...
The motor mounts for Both motors are 19, 15/16" from the foreward mounts to the aft mounts....
And,..
Both motors are 22, 1/2" between the front mounts,...
And,...
The mounts are equal to the crankshaft centerline.....

So,..
In theory,... They'll Both drop into the Same Holes.... Your results may vary......

 

[Cptkid570]

Re: motor mount question 5.7 vs 7.4

Thank you for your responses everyone. I really appreciate all of the help.

I currently have 2 boats. A 19' bowrider that is running rough (I had a different post on iboats about that yesterday) and a 26' boat that I don't really like, but love the engine... I want to find a 23' or 24' boat to put that engine in.

So, that's why my name seems to be popping up a lot with bunches of questions.

 

[Bondo]

Re: motor mount question 5.7 vs 7.4

Ayuh,... No Problem,...

You Forced me to teach myself something this morning.....

 

[Cptkid570]

Re: motor mount question 5.7 vs 7.4

Ayuh,... No Problem,...

You Forced me to teach myself something this morning.....

What was that? Learning the distances for the mounts for the 7.4 vs 5.7?

 

[Bondo]

Re: motor mount question 5.7 vs 7.4

Ayuh,... Had to drag out the Book,+ Look....

I'd have Thought that the BBC's mounts would be slightly forward,+ Wider...

 

[Cptkid570]

Re: motor mount question 5.7 vs 7.4

Me too. Only reason why I thought they'd be close is because so many boats come with the option of a 5.7 or 7.4 engine. I figured the boat manufacturers wouldn't want it to be too much work in putting either in.

 

[dan t.]

Re: motor mount question 5.7 vs 7.4

this is an example of chevy interchangeability, all small blocks,all big blocks,same bellhousing,same mounts