Engine coupler question

"Over the winter I will be rep

"Over the winter I will be repowering my boat from a 1994 Mercruiser 5.7 4 barrel to a 2006 Mercruiser 350 Magnum (not with FI though, obtained a long block and will add intake and 4 barrel). The old engine is rated 235hp and the newer one should be close to 300hp. Will the 14 year old engine coupler work fine or should I get a new one?"

Check the condition of the spl

Check the condition of the splines. They should NOT be rounded on the edges but square cut.
If you have the cash replace it w/a new one.

"a 14 year old anything that y

"a 14 year old anything that you will have easy access to is in my opinion a no brainer.Replace it, the added power would or could strip it.

Also the 300 hp is rated on EFI/computer controll so running a carb with out that system will take some really good tunning to achieve those numbers."

"According to the shop manual

"According to the shop manual that I have, 1988-89 is the last time a 454 was mated to a alpha 1. It was a 454 magnum rated at 365hp. Do all alphas use the same engine coupler or are there differant ones depending on if it's mated to a 4 cyl. or big 454?

Kghost - did a little research, the '06 350 magnum is rated 300hp with the mpi, I thought it was 330hp. Maybe I'll get 280-290hp with a Q-Jet and an Edelbrock Performer intake??? I'm looking for more low end torque up to 3500rpm's mainly."

Think about a drive shower for

Think about a drive shower for the Alpha. 300hp is a lot for those drives as i recall.

"[b]"Do all alphas use the

""Do all alphas use the same engine coupler or are there differant ones depending on if it's mated to a 4 cyl. or big 454?"

Ayuh,...

There were Several Couplers used,...
But,..
The Differences are How they Mount, Not about their inherent Strengths...
The I4 coupler is Just as Strong as the 454 Coupler...."

"The coupler was not the issue

"The coupler was not the issue with the 454 and the alpha 1,

The issue was the upper gear case blowing apart due to the torque on the gears.........Thus the BRAVO 1. The couplers as far as I know are the same. Only difference is changes due to design of the coupler itself and flywheel changes with engine design changes. The older couplers mounted to the flywheels with 6-8 bolts in a tight diameter(i dont remember exactly how many) the newer ones mount with three bolts in a very wide diameter.

As far as power goes if you do some research and you are buying a remanufactered long block a simple cam change and a calibrated quadrajet from JET will get you to 300+ hp easily.

The normal 350 replacement block is the truck block. It has typically been a 260 hp replacement.

I am not sure of the 1990's and newer but close. The ONLY difference between the 260 hp and the 350 mag (both carbed) was the intake and air cleaner ( spark arrestor)

I did the parts research once to see for my self.

So for you to achieve 280 hp is easy with a good aluminium intake and a properly calibrated carb.

The holley 650 spread bore marine cab is a very good replacement carb. I have used a couple on 2bbl to 4 bbl upgrades. although it takes some mechnical finess to get the linkage set up but not that difficult. Also look for the 350 mag flame arrestor. I got mine thru napa belive it or not."