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View Full Version : What can I do with this thing?!



Tall Cotton
12-09-2013, 04:12 PM
I was bequethed a '97 Vortec from a Tahoe and am thinking about putting it in my Cobalt GT-500 Corsican "Splash" restoration/rebuild. The good: Dimpled rods, 906 heads, solid block. The bad: Two bolt mains, no accessories nor intake.
I was thinking on rebuilding it to stock and mating it up to an Alpha.
Is this a worthy endeavor?
What ratio Alpha should I look at?
Any big differences between this engine and an actual Mercruiser - cam specs, pistons, crank, bearing tolerances, other internals, ect?

Thanks.

MOP
12-09-2013, 05:33 PM
Not to worry about the 2 bolt bottom we do not spin them high enough to worry, pistons,cam are different. I would not hesitate to build it to a tad over 300 mated to an Alpha.

Tall Cotton
12-09-2013, 10:44 PM
What type of pistons am I looking at and where can I get cam specs? One person advised flat top pistons and an RV cam.

MOP
12-10-2013, 11:35 AM
The standard marine piston is called hypereutectic, they will stand up to constant high load. I would use any decent brand of forged pistons, configuration flat or dish depends on what compression you are shooting for. for a mild build 9:1 which will burn 87 pump gas. I ran 9:125 on my 383 with good results. For a cam stick with marine, on your crank use Moraine 500 or equivalent bearings, a standard crank is fine for a moderate build. 325 to 350 is a good HP range for reliability, the Alphas have been known to handle 400HP but if you drive them hard they do not live long.

Tall Cotton
12-11-2013, 09:09 AM
The standard marine piston is called hypereutectic, they will stand up to constant high load. I would use any decent brand of forged pistons, configuration flat or dish depends on what compression you are shooting for. for a mild build 9:1 which will burn 87 pump gas. I ran 9:125 on my 383 with good results. For a cam stick with marine, on your crank use Moraine 500 or equivalent bearings, a standard crank is fine for a moderate build. 325 to 350 is a good HP range for reliability, the Alphas have been known to handle 400HP but if you drive them hard they do not live long.

That there is some good solid info that I can use. MUCH appreciated!