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New Project boat 26 Bertrum hard top

MAMako21

New member
I just picked up a 26 foot Bertrum 1973. Hull is perfect as is cabin. The rear floor needs some work as do powering it. Original set up was 2 I/O's the 470 inline 6 135 HP each. The out drivers were off the boat and long gone according to the owner and one engine is junk. I have a 1990 ford 5.0 that I rebuilt several years ago which I was looking at another project hull and the sale fell through the 5.0 is 330 HP. I am thinking of redoing the motor mount and going with the V-8 saves on weight and mount a single out drive. Not looking for a speed boat just one I can use to chase stripers in the northeast. going to replace the tank and go with 2 80gallon saddle tanks. Any thoughts on outdrive ? engine Choice? what ever?
 
Ayuh,.... There 3 Bert 26s in the marina I hang out at,...
1 of 'em is owned by the guy I work for, another by his Brother that owns the dockage,
'n the 3rd by their best friend, that owns the marina,...

I think yer confused 'bout the motors,...
The I-6s are the Merc 165s,...
The 470 is a Merc redheaded step-child that did 'bout 170 hp,...
The 135 hp motors were the I-4 Chevys,....
2 of the 3 boats above are I-6, 165 hp twins with MC-1 drives,...
The 3rd is twin Honda outboards,.... 250s I think,...
All are 'round '79 vintage, from somewhere in Michigan, 'bout 4 or 5 years ago,....

I've been fightin' the fuel tank of Eric's, the fiberglass delaminated, 'n played 'ell with the fuel systems,....
I cut it outa the hull earlier this year,...
Hopin' for a new aluminum tank in the spring,... then back through the fuel pumps, 'n carbs,...

If yer 5.0l is makin' 330 hp, it's probably way over built for a reliable boat motor, with wet exhaust,...
 
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The 5.0 that OMC was using was 350 HP and generally well received if maintained. The 330 I rebuilt using Mercury marine parts. Had it dynoed last year and came out at 328HP. Your right the I-6 at 165 hp are likely what was in it both engines are in really rough condition. one the block has 2 cracks and is total junk the other I have not gone too far with but seems also not to be really worth the effort since neither has out drives attached. Got the hull for $650.00. First Bertrum for me, I have mainly worked on Mako's, also first O/I repower but I have done straight inboards on several boats Trojan being the most recent. Was trying not to under power or overstress a single on a heavy boat. Yes, this is a freshwater cooled engine.
 
The 5.0 that OMC was using was 350 HP

Ayuh,..... What year,..?? What Model,..?? 250 hp is more like it,.....
Had it dynoed last year and came out at 328HP.

What cam, 'n other components,..?? at what rpms,.. ??

High horsepower automobile motors suffer reversion when stuffed into boats, 'n die gruesome deaths,....

Boat motors need to build Big torque down low,...... 5000 rpms, Tops,....
 
Ok
Had to pull out my report 328 @ 4400 rpms 310 foot lbs of torque 3000rpm Torque curve is excellent on these engines starts off at 120 foot lbs @ 700 rpm's. potential pairing It with a Bravo or a Gn2 ratio either 1.47 or 1.63 . The engine I based the build on was the cobra EFI late 90's
 
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Let me just add I rebuilt this engine for marine use from the block on up. I had the engine for my 1990 Mustang Rag top that I was originally going to super charge for the car instead started a marine rebuild from stripped down block on up. It is with a few modifications to pistons and heads 100% MARINE GRADE from valve guides, gaskets, wiring on up. Not my first marine engine and not my first 302 rebuild.
 
potential pairing It with a Bravo or a Gn2

Ayuh,.... Biggest problem I see is,....

Merc hasn't build a flywheel cover for a Ford, since they dropped 'em in the '70s, 'n they used the MC-1 rear motor mount spacin', which is to wide for any of the Merc drives since the early '80s,.....
'n of course, Marine parts stuff is way more expensive, like exhaust manifolds, which also may not line with with the newer Merc y-pipes,...

Chevy is King in the marine motor world,....
 
Well may have to go to OMC outdrive then. I can get a rig off of a 1996 that is in good shape and just replace the lower unit. More concerned with the HP and weight change effecting performance of the hull even with20 gallons more of fuel I is going to be light in the transom. Hoping the 330HP will perform as well as the duals did on the boat.
 
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