L72 Big Cars

[Paul D]

Some of the unique neat "one off" things on '66 big car L72's are the four core HD radiator, idler pulley and bracket like '65 Z16, two snout air cleaner (different from '70 Z28), large Corvette exhaust manifolds, exhaust system and hangers with no resonatiors and turn downs behind rear wheels. and List 3247 carb ('66 L72 Corvette was List 3247).

Also, for plants that included options on the trim tag, an X indicated close ratio 4 speed (M21 or M22) which was only installed on L72 equiped big cars.

I have a '66 Impala SS L72 with in-dash tach, console gauges, M21, TI, and PS. Aztec Bronze Metallic/Black vinyl top/black interior. It runs like a scaled rabbit!

Paul

[QQGSX]

I have never heard of the "X" theory. However, I have heard that a "Q" on the trim tag indicated a 427/425 4 speed. My understanding is that the 1 through 5 option lists on the trim tag were to notify the Fisher body employees where to drill certain holes in the body for those options.Of course, not all factories put options on the trim tags.

I may be mistaken, but I believe the list # on the 427/425 big cars was 3246 in 1966.

Paul, where was your "66" built?

[Casey Marks]

NICE stuff !!!!

[Paul D]

QQGSS, Yes, I believe your right on both comments. It is a Q on the trim tag that indications close ration 4 spd, and L72 (not an X). Also, the L72 carb List # is 3246 for big cars as you state. Sorry about my typos!

My car was built in St. Louis, S in the Vin #. It came from the factory with a 3.36 posi and M21.

Paul

[mssl72]

Thanks for the nice comments guys. It was fun to get them all together. The tan car is currently in Scottsdale getting ready for it's spotlight on Thursday. About the black car, I forgot to mention that the original window sticker is with it. It is the most loaded out of the 3 including power steering and brakes, AM/FM multiplex, and the comfort and convenience package. My car (blue) and the tan car both do not have power steering or brakes. It keeps you on your toes sometimes. As for gears, mine is a DN code, 4.10:1, black, DM code 3.73:1 and the tan, DH code 3.31:1. Transmissions are M20, M21 and M20 respectively. The Holley 3246 is the carb that would have been installed on an L72 passenger car. There is a little twist to that though. The 3246 is an "EE" code. On the build sheet for the tan car it shows an "EF" code. I find that odd that an "EF" code, Holley 3130 (1965 396/425 L78 carb) would be called out for a car built the 4th week of April 1966. It could have been a typo, maybe the fact of it being built in a BOP plant with some possible different codes.

[Turbo Regal]

One question for the experts: I know the L72 was available in big cars in '66,'68 and '69. Why none in 1967?

[Paul D]

Nathan, What I've heard about the '67 cars not having an L72 is that the Corvette powers prevailed and politically got it killed for the '67 model year. Apparently they thought an engine in the big car that was comparable to the Corvette would dilute the performance image of the Corvette.

Also, it's interesting to note that the Z24 option on the '67 big cars has the unique three chrome "stacks" on the top of the hood indicating that at least at one time Chevrolet was planning for a Tri Power engine in '67 big cars similar to the Corvette L71 427 435 horse L71.

My guess is that politics won out in 1967, but in '68 and '69 the L72 again became a RPO for big cars. Maybe the Corvette guys felt that with the Tri Power options and the L88 they were adequately maintaining there image as Chevrolets performance leader. Of course, then you have to ask yourself what happened in 1970 with the Chevelle LS6 450 hp option??

My two cents.... for what it's worth.....
Paul

[JoeG]

3's a charm--------------

[mssl72]

Maybe one day I can get my car to one of SCR events. Do they let luxury cars in? Here's a few interior shots.

[SS427]

Yeah, me too. Then maybe we big car owners can show some of the Pony car owners that this big 'ole iron does have some muscle.