It's a 1972 18' Cobalt Jet with a OMC installed 245 HP (gross rating, I think) Chevy 307 V8 coupled to a Jacuzzi 12YJ jet drive. Seems to be very well made, nicely appointed boat by 70's standards, but by the time I got it, the decks were rotted, the jet drive was worn out, and the engine had water sitting in the pan for 6 years... but somehow still ran once I changed oil. How, I'll never know, as when we finally blew it up spinning donuts and figure 8's, we had run 2 seasons on it only to find that the block was cracked in a couple locations in the lifter valley, a head gasket was blown, and somewhere along the line one of my friends switched up spark plugs which led to preignition that I didn't catch as fast as I should have. They may be archaic, but Chevy v8's are surely as close to invincible as engines get.
This was last summer after we rebuild the jet drive, and put in fresh decks:
http://vids.myspace.com/index.cfm?fusea ... =825112037
After blowing the 307, the logical budget fix was to locate and install a marine grade 350 shortblock, with the same tricks OMC installed on the 307 in the way of cam, heads, intake, and 4bbl carb to boost power from the pitiful ratings as installed in the trucks of the time. Cept I was shopping around and came upon M&R engine out of Glendale, offering a 383 shortblock for 1500, with forged pistons, aftermarket I beam rods, and a new nodular iron crank. They even machined it to marine specs and clearances for me. Sweet.
This is what I got so far:
-M&R 383 stroker shortblock, 4 bolt, new nod iron crank, forged I beam rods, FHR KB pistons, -18CC dish pistons for 8.5:1 (required for severe duty/continuous load use on 87 gas)
-Rebuilt 487X cyl heads with "Z28 HO" style springs - 1.94" Intake 1.5" Exhaust
-Comp Cams/Hardin Marine Xtreme Marine 270H cam .480/.489" lift 112 deg LSA, 270/286 adv duration
-Edelbrock Performer RPM intake manifold, Quadrajet
-Custom built Franken-Quadrajet using 454 truck castings, special tricks by Recarbco Fuel Systems. There was a Holley 650 DP on there, and the throttle response and driveability was horrible despite full rebuild and live engine tuning. The QJ was actually faster on GPS, too.
-7Qt. drag racing oil pan (to avoid running the pump dry again)
-Melling H55A standard volume, high pressure oil pump.
-Other goodies like a marine flash suppressed 1 wire Delco alternator to replace the external reg Prestolite
So what do y'all think?
