1967 3904351 and 3916321 427s out of boat several questions

[Misfit]

Hi
I just joined this forum today but sadly have not owned a Corvette for over 15yrs. I do visit this forum often and I hope I can get some info on a couple of motors I just purchased out of an old Hatteras sport fisherman. They are a counter rotating 3916321 and a standard rotation 3904351 427s Both we're running upon removal and were freshwater cooled. Eventually they will be completely torn down and inspected and sold. What I would like to know is there anything to look for regarding their conversion to marine use aside from the heads, cams, etc that would make the blocks and cranks unsuitable to a Corvette restorer . They are Crusader 320 hp Motors 4 bolt steel crank motors with standard rods and the opposite rotation motor has a gear drive in place of a chain. The decks are stamped with the engine Ids but no vins, LH and RH are in the place of where the vins would be stamped.


Thank you
Misfit

 

[JohnZ]

They are a counter rotating 3916321 and a standard rotation 3904351 427s Both we're running upon removal and were freshwater cooled. Eventually they will be completely torn down and inspected and sold. What I would like to know is there anything to look for regarding their conversion to marine use aside from the heads, cams, etc that would make the blocks and cranks unsuitable to a Corvette restorer. The decks are stamped with the engine Ids but no vins, LH and RH are in the place of where the vins would be stamped.


Thank you
Misfit

I can't think of anything block-wise that would make them unsuitable - depending on casting dates, the 351 will work for a '67, and the 321 would work for a late '67 or '68. The front block pads will take a 50-point deduction for the incorrect machine code stamps and missing VIN stamps, but will keep the 38 points for the pad surface (assuming the casting dates are within 6 months prior to the car's build date).

 

[Misfit]

Hi John
Thank you for the quick reply. I guess my main concern was if the counter rotating 6321 may have had the front of the block modified to accept a gear drive. Secondly if the crankshaft oil hole chamfers as well as the rear main journal may be different due to rotating in the opposite direction. I have heard that the 427 Fords had a knurling on rear main journal that if turned opposite of its application would actually pump oil out of the motor while running. One thing I found of interest is that the flywheels used on these motors were flipped around to mate with their marine drives. So in addition to the collectible motors I also got two dated flywheels which have never touched a clutch. Once these motors are sorted out I really hope they can find a home in 67 Corvette, still my dream car for over 40 yrs.

Thanks Again
Misfit