1966 L72 Biscayne

[Tarrytown SS427s]

The 3 on the vin tag means it was built as a 6 cylinder Biscayne originally.

[jeffschevelle]

Already answered in the other thread posted by the O.P.:

https://www.yenko.net/forum/showthread.php?t=183338

POP also confirms 6-cylinder car originally.

[dykstra]

Very cool! Welcome to the best site on the net.

[Bill Pritchard]

Welcome to the site. To answer some of your questions....

1. Unlike the prior poster in this thread 'kenbrogan', your car's VIN indicates it was originally produced with an 8 cylinder engine, so that's a good start.

2. Rear axle and trans pictures you have posted have good assembly dates that line up with your car's scheduled production date (from the Trim Tag) of 07A (first week of July). The EJ code on the rear axle indicates it was originally equipped with a 4.88 positraction differential, and had metallic brakes....both very strong indications of a car ordered with drag racing in mind. I believe the transmission should have a partial VIN stamping also, but it could be up on the top of the transmission where it would be extremely difficult to see with the trans still in the car.

3. Unfortunately, if there's no build sheet in your car now, there's no way to get one.

4. Not at all unusual to have no factory tach, as anyone who was going to be doing serious racing would install their own aftermarket tach....the factory pieces were never known for being perfectly accurate, and often were located out of easy viewing.

Can't help with your missing/incorrect pieces but others here might have some ideas.

[AdamApple]

thank you for your insight.
i was thinking the same thing about the tach, being a drag racer myself.
i am looking forward to finding the missing pieces.
much appreciated.

[cheveslakr]

.......also a q code in group 2 on the trim tag, so it's a 4 speed from factory. Some say that indicates a M21, but not positive if that's conclusive. Love the car!!

[AdamApple]

when i did my research before i purchased, i thought the same.
the 2Q means an M21 and the fact that the rear gear is more than 3:31 (in this case 4:88) meant that it can only be a real L72 because you couldn't get that gear otherwise.
4 core radiator, no power anything...
of course, all of that could be faked but like Bill Prichard said, the date codes on the motor and trans seem right....

thanks!

[Bill Pritchard]

Originally Posted by AdamApple

like Bill Prichard said, the date codes on the motor and trans seem right

That would be trans and rear axle....

[fsc66]

Hard to see but looks like it does have a tach. When you ordered a 4-spd with 325, 390 or 425 HP engine it included the tachometer. If so is the tack a 7K tach with a 6K red line?

Also as stated, he M21 was available only with the L72 motor. Also the 4.10 through 4.88 rear axle ratios were only available with the L72

Paul

[AdamApple]

Sorry Bill Pritchard, you're right, my mistake.
Paul, i heard it both ways, that it came automatically, or you could option the tach, but in this case, it is a clock.
and i also thought the M21 was only available with the L72 as well as the rear gear upgrade, of which i have both and the 2Q code backs that up