BHP Explanation...

[GerryLP]

I think that Tom's logic is well founded. It would probably include all the common accessories included on the base model vette.

 

[jmp]

Makes sense. So those guys with more, non-standard accessories would actually have lower hp. I wonder how much lower?

Oh, regarding AIR, I don't think that was a standard option, at least not in '72. My LT-1 doesn't have AIR, and the dealer option sheet that I have for the car doesn't mention AIR. The original exhaust manifolds on my car also do not have provision for the AIR tubes, either.

So, since my car has no accessories (no AC, p/s, AIR), it should be putting out the max hp it can!

 

[Tom73]

Oh, regarding AIR, I don't think that was a standard option, at least not in '72. My LT-1 doesn't have AIR, and the dealer option sheet that I have for the car doesn't mention AIR. The original exhaust manifolds on my car also do not have provision for the AIR tubes, either.

Hummmm..... Chevy used the A.I.R. system on the performance engines as it stole less HP then did the Controlled Combustion System (CCS) that was used on non-A.I.R. cars. In '70 the CCS was used on all Vettes except the LT1 which had the A.I.R. system. In 71, all Vettes used CCS except LT1's and LS6's which continued to use the A.I.R. system. In '72 all corvettes returned to the A.I.R. system except for CKW and CKX coded L48s. For '73 all Vettes used the A.I.R. system. In 74 all used the A.I.R. system except the federal emission L48 with automatic trans.

I think you need to check closer on your LT1. It should have had the A.I.R. system on it. What does the emission sticker above the brake master cylinder say?

tom...

 

[jmp]

Unfortunately I don't have my car or my documentation here with me at work, so I can't quote those. However, according to Idaho Vette, and the CAC model center, the AIR option, K19, was only available on 3912 vettes in 72. The LS5 and LT1 account for 5654 vettes, so... Unless you are saying that K19 only showed up on the dealer sheet as an option if it wasn't already standard? But I think other "standard" options, such as the shoulder belts that all LT-1s came with, are on that sheet.

Also, there's the question of my exhaust manifolds, which have been verified as original, don't have the hookups for AIR.

The dealer sheet did have an option code for Canadian emissions equipment, so maybe that has something to do with AIR?

Anyway, I'll check the emissions sticker and some other stuff tonight.

The attached pic is the only one I have of the engine bay, but you can kind of see that there is no AIR pump.

 

[Tom73]

I have seen that listing for the K19 RPO code for the A.I.R. but have never been able to figure it out as AIR was not an option, it was emission equipment. Here is my thinking. The L48 coded CKW and CKX did not have the pump, all other engines did. But there are L48s coded CDH and CDJ listed as "emission control". I bet that the K19 option was used on these two engines going into calif. If so, there would have been 3,912 L48's for Calif. The other 17,448 L48s went to the other 49 states and for export.

If you car was a Canadian export, it should have a Canada export sticker on the end of the drivers door and an tire pressure sticker below the emission sticker under the hood (which I do not see in the pic). But if it really is a Canadian car, then you can get a copy of the build sheet from Chevy Canada

tom...

 

[jmp]

But if it really is a Canadian car, then you can get a copy of the build sheet from Chevy Canada

Truly? As in the build sheet that was on the gas tank?

Wow! I thought Chevy didn't keep records like that. I'll have to look into it.

I'll look for those stickers too.

 

[Tom73]

Wow! I thought Chevy didn't keep records like that. I'll have to look into it.

Only Chevrolet of Canada as it was part of the import process.

tom...

 

[JohnZ]

ALL '72 LT-1's had A.I.R. - K-19 doesn't show on LT-1's as an option, as it was part of the standard equipment for that powertrain; the only time it showed as a separate option was on all Federal LS5's (which were not available in California at all) and it was included as a part of RPO NB2 on California-bound L48's, which included the A.I.R. system within the NB2 option. Your exhaust manifolds are not original to the car; the originals were casting #3932461, with four holes drilled in each one for the A.I.R. tubes. This same casting number was used in many different Corvette applications from 1969-1980, always with A.I.R., with several different arrangements of drilled holes for A.I.R. (some with two holes, some with four).

Many owners removed all the A.I.R. equipment from their cars in the 70's, in the (mistaken) belief that it detracted from performance (it didn't); as those cars have passed from owner to owner over the last 30 years, many of the subsequent owners now believe they came originally without A.I.R., but they didn't.

 

[jmp]

Well, if this is true, then I'm going to be slightly p.o.'d. I was told by two separate 'vette dealers/shops that the cars was (mostly) original -- one had previously "owned" the car and had done some resto work on it, while the other was never directly involved with the car except that the owner knew the guys doing the frame-off restoration a decade or so ago (he remembers the car from back then). I had the car specifically checked out prior to purchase, 'cause I knew that I didn't know enough about 'vettes to do it myself.

I also have a documented appraisal that does not mention changed manifolds.

That being said, I'm only going to be slightly p.o.'d 'cause I knew the car was not completely original -- the owner never claimed it was -- because a couple of owners ago the original block had cracked when the 'vette was incorrectly stored over the winter. So, I didn't expect matching numbers and I didn't pay for matching numbers. Still, I want to know exactly what I do have!!!

Again, when I go home I'll look up some stuff on the car and in the documentation. Then if I can't prove that it did not come with AIR, I will be making a few phone calls!

Crap! I want my car as original as possible (don't ask me why, I can't explain it! ) so this may mean I'm going to have to find an AIR system. ad

 

[jmp]

moving the AIR discussion

I've decided to move the A.I.R. discussion to a new thread in the LT-1 registry forum. I hope some of you will check it out and help me out!

Thanks.