1966 L-79 HT vs HP suffix code

[Edward M.]

I looked at a nice original 66 coupe yesterday. The car is an original L-79, A/C and P/S car. Engine assembly date is Jan 25th. The engine pad is clean and very original looking, and has an HT engine suffix code. The engine code matches the protecto-plate information for the car.

I know that this combination of options should have an HP engine code. I also know that there has been quite a bit of discussion about this over the years, and that HT is an acceptable code in this situation.

The interesting thing is that the passenger side valve cover has the engine code labels on the back side of it. The code on the valve cover is HP. The labels are clearly replacements, but I suspect that they replaced what was originally on the car.

Have we seen a situation where the code on the valve covers did not match the code on the engine?

Thoughts?

[Joe L.]

Re: 1966 L-79 HT vs HP suffix code

I looked at a nice original 66 coupe yesterday. The car is an original L-79, A/C and P/S car. Engine assembly date is Jan 25th. The engine pad is clean and very original looking, and has an HT engine suffix code. The engine code matches the protecto-plate information for the car.

I know that this combination of options should have an HP engine code. I also know that there has been quite a bit of discussion about this over the years, and that HT is an acceptable code in this situation.

The interesting thing is that the passenger side valve cover has the engine code labels on the back side of it. The code on the valve cover is HP. The labels are clearly replacements, but I suspect that they replaced what was originally on the car.

Have we seen a situation where the code on the valve covers did not match the code on the engine?

Thoughts?

Ed-------


Well, in the vast majority of cases the valve cover labels "left" the engine way before anyone cared to look at them.

In any event, I could easily see how a situation that you described could have occurred. There is very little difference between an "HT" and "HP" engine assembly and all the differences involve easily changeable, "peripheral" components. So, I would think it's very possible that an "HT" coded engine was converted at Flint to an "HP" coded engine, perhaps to fill a St. Louis engine order when there were not enough "HP" coded engines available at the particular time the order went out. For PRODUCTION purposes, probably all that was important was the valve cover labels since that was how assembly workers identified the engines.

[Patrick B.]

Re: 1966 L-79 HT vs HP suffix code

I once had a very original low mileage 67 327/350 coupe with air and PS and a HT coded engine. I had the original sales documents showing PS and the protectoplate also showing the HT engine. At some point I dropped the tank and much to my surprise the PS was not on the tank sticker. I think the dealer must have added the PS for the original purchaser before the sale.

[Edward M.]

Re: 1966 L-79 HT vs HP suffix code

A/C or P/S or both having been added is certainly one of the possibilities.

[Larry M.]

Re: 1966 L-79 HT vs HP suffix code

I once had a very original low mileage 67 327/350 coupe with air and PS and a HT coded engine. I had the original sales documents showing PS and the protectoplate also showing the HT engine. At some point I dropped the tank and much to my surprise the PS was not on the tank sticker. I think the dealer must have added the PS for the original purchaser before the sale.

I agree. My experience is that in these situations, POWER STEERING was added to the car at a later time in its life. It is very difficult (or impossible) to detect add-on PS to a C2 car if it is done correctly using GM factory parts.

FWIW.

Larry