Early 72 LT-1 Engine specs.

[Marc B.]

Hello all,

My first posting here...Long time member but first post on this Forum...

I have 2 original ``build sheets`` of my early 1972 LT-1 (vin 500278, build date A17) showing engine specs as 330 / 275 HP. These are 1971 specs. Were these early cars build with the previous year specs ?? A mistake ?? Anyone has info on this ??

Car was built with no options aside from 3.70 gears...Quite a beast I must say...

Help & info appreciated,
Mk

[Lynn H.]

Re: Early 72 LT-1 Engine specs.

Marc,
Welcome to the board...
When you say "build sheets", are you referring to documentation from your car such as an "order copy", or "tank sheet"??
Lynn

[Marc B.]

Re: Early 72 LT-1 Engine specs.

Lynn,

Sorry, I should have been clearer...Both documents are Corvette Order Copy. One was under the dash (between tach - speedo) the second one is the ``tank sticker``. They are both in vg condition & the ``dash one`` has a purple back side...

Hope this helps a bit,
Marc

[Lynn H.]

Re: Early 72 LT-1 Engine specs.

Interesting...What code is on the engine stamp pad?
The 71 motor would have been a CGZ,
while the 72 would have been CKY (assuming it did not have A.I.R.)
Lynn

[Lynn H.]

Re: Early 72 LT-1 Engine specs.

I believe the code would be on the "Order Copy" also.
Lynn

[Marc B.]

Re: Early 72 LT-1 Engine specs.

Engine stamp pad shows a CKY code. Didnt all LT-1s had AIR Systems ??

yes both copies show the following: CKY 2VLT110 330/275 HP TURBO-FIRE 350 V8

Marc

[Lynn H.]

Re: Early 72 LT-1 Engine specs.

Engine stamp pad shows a CKY code. Didnt all LT-1s had AIR Systems ??

yes both copies show the following: CKY 2VLT110 330/275 HP TURBO-FIRE 350 V8

Marc

I think they did, I was looking in the pocket spec guide vol-2, which shows two different codes for the 72-LT 1 (CKY and CRT w/K19). Now looking in vol-1 of the spec guide it states that none of the CRT code motors were ever produced. Hopefully Terry M will jump in on this one, as he would know way more about this than I. But the CKY code is for the 72-LT 1, rated at 255hp.
Lynn

[Joe L.]

Re: Early 72 LT-1 Engine specs.

Engine stamp pad shows a CKY code. Didnt all LT-1s had AIR Systems ??

yes both copies show the following: CKY 2VLT110 330/275 HP TURBO-FIRE 350 V8

Marc

Marc------


Yes, all 1970-72 LT-1's were equipped with AIR.

I expect the reason for the horsepower ratings you've found on the build sheets relates to some early "dual ratings" shown during a transitional period, although I do not understand why 275 hp rather than 255 hp is shown after the slash.

1972 was the year that horsepower ratings changed from SAE GROSS to SAE NET. There was really minimal change from 1971 to 1972 as far as LT-1 engines go except for the deletion of K-66 TI ignition (earlier, when this option was available on certain engines it resulted in no rated horsepower increase, so I expect there was none between 1971 with K-66 and 1972 without K-66). So, I expect the SAE GROSS rating of the 1972 LT-1 was 330 HP.

The SAE NET horsepower was 255. However, I suppose it's possible that early on this rating was 275. I've never seen anything to support that, but I think it's possible.

[Lynn H.]

Re: Early 72 LT-1 Engine specs.

Marc------


Yes, all 1970-72 LT-1's were equipped with AIR.

I expect the reason for the horsepower ratings you've found on the build sheets relates to some early "dual ratings" shown during a transitional period, although I do not understand why 275 hp rather than 255 hp is shown after the slash.

1972 was the year that horsepower ratings changed from SAE GROSS to SAE NET. There was really minimal change from 1971 to 1972 as far as LT-1 engines go except for the deletion of K-66 TI ignition (earlier, when this option was available on certain engines it resulted in no rated horsepower increase, so I expect there was none between 1971 with K-66 and 1972 without K-66). So, I expect the SAE GROSS rating of the 1972 LT-1 was 330 HP.

The SAE NET horsepower was 255. However, I suppose it's possible that early on this rating was 275. I've never seen anything to support that, but I think it's possible.

Joe,
In volume 1 of the pocket spec guide on the "1971 Engine Power Teams", page for the LT 1, it shows the rating as 330hp(275hp*), and at the bottom of the page says:
*SAE net (as installed) horsepower rating
So, I believe it is the transitional period where they listed both the old and new style ratings. So Marc seems to have the 71 hp rating with the 72 code.
Lynn
Also, the vol-2 of the pocket spec guide nor the special membership edition (Corvette Restorer V16#1) show this 71 rating this way, I only see it listed like that in the first pocket spec guide.

[Marc B.]

Re: Early 72 LT-1 Engine specs.

Hello

I dont have a scanner but was able to make a picture of the Corvette Order Copy.

Could the engine be build to 71 specs ?? Or it's just the info on the build sheet that refers to ``old`` numbers during this transitional early assembly period ??

Other early 1972 Corvettes reported like this ??

Marc

[Mike G.]

Re: Early 72 LT-1 Engine specs.

Hello


Could the engine be build to 71 specs ?? Or it's just the info on the build sheet that refers to ``old`` numbers during this transitional early assembly period ??

Marc

71 and 72 were pretty much built to the same specs. the difference in the hp rating is because they used a different way to measure the horse power. one is gross hp and the other is net. motor is pretty much the same thing.

[Edward J.]

Re: Early 72 LT-1 Engine specs.

Joe, with the LT1 in 72 if the car had A/cond. did the horsepower drop for that resaon?possiable something to do with the high rpms the belt would fly off.

[William C.]

Re: Early 72 LT-1 Engine specs.

The engine build would correspond to the engine ID stamping on the pad. The other stuff is St Louis stuff, how to build the car, not anything controlling the build of the individual parts.

[Joe L.]

Re: Early 72 LT-1 Engine specs.

Joe, with the LT1 in 72 if the car had A/cond. did the horsepower drop for that resaon?possiable something to do with the high rpms the belt would fly off.

Edward------


The advertised horsepower rating did not change whether or not C-60 was also installed.

For 1972, references to engine horsepower were dropped from emplacement anywhere on the car. So, there was no reference to horsepower on the console data plate and there were no air cleaner (or, valve cover) decals.

As I mentioned previously and has been otherwise substantiated from NCRS references, it may be that early-on, before things were completely "worked out", the SAE NET rating for the LT-1 was set at 275. It must have been real early, though. The Oct/Nov 1971 issue of Corvette News, which obviously went to press well before that time, specifies the 1972 LT-1 rating as 255 SAE NET HP.

[Edward J.]

Re: Early 72 LT-1 Engine specs.

Joe, I thought about it afterwards , I was thinking of the tach redline was lowered. w/ c60