68 engine code ID problem

[Calvin C.]

Thanks for helping. The problem is actually between two references. I am considering a 68 convertible to purchase for restoration. The VIN has for engine ID, "V1201HP" My Chevrolet by the numbers indicates this "HP" to be a L79 327/350 hp. and "HT" also as a 327/350hp motor. My NCRS Corvette Spec Guide says the "HP" is a base 300hp motor and the "HT" is the L79 350 horse. Which is correct and what am I missing. The heads look like 1.94 valves which leads me to believe it is a base motor, but the head numbers for a 2.02 is the same. thanks Cal

[Tom D.]

Re: 68 engine code ID problem

In '67, the 300 HP codes were HE HH HR and HO. HO was for the Powerglide combination. (I have a '68 block with HO, for automatic but not a PG.) HE was for three and four speed transmissions. HH and HR indicated air pumps (A.I.R.).

For 1968 some of the same codes were used. HP and HT indicate the 350 HP versions, where HP means with air cond. Apparently you could not get 350 HP and the automatic transmission in 1968...

Could the heads have been swapped for 300 HP versions? Are you able to measure the valves?

[Calvin C.]

Re: 68 engine code ID problem

HE (being manual) and HO (being AT) also show as base engines for 68, however the HP and HT will ID Air and special cam. Yet the two references seem to oppose each other as to which is the 350 horse. Yes the heads are off and I can measure them, they look like 1.94 but are they original. thanks Cal

[William C.]

Re: 68 engine code ID problem

Are you looking at the stamped code on the pad in front of the block, drivers side? If so, HP would be a base motor car, HT would be the 327/350, from the GM part book engine ID reference. I'd bet on that and The NCRS guide over "chev by the numbers"

[William C.]

Re: 68 engine code ID problem

In a '68, look at the pistons if the heads are off. 300hp has flatop pistons, 350hp has a domed piston...

[Tom D.]

Re: 68 engine code ID problem

I agree with Bill C.

[Dick W.]

Re: 68 engine code ID problem

Latest and greatest from the most current TIM & JG The NCRS Spec Guide has been known to contain errors.

HO 300 327 Turbo Hydra-Matic Q-Jet


HE 300 327 Manual (3- or 4-speed) Q_jet


HP 350 327 Manual w/ PS & AC Q-Jet


HT 350 327 4-speed Sp. Cam Q-Jet

Note the HP engine is with A/C

[Monte M.]

Re: 68 engine code ID problem

Bill has it right I think.
Plus, if you are dealing with a 68 Corvette short block, odds are that they are the 68, 194 intake valves.

On 461 casting it is very easy to see if they have had 2.02 valve put in by the seat faces touching.

On the 68, 291 heads it was a very different situation. You could add the 2.02 valves like you did on the 194 heads, but from the factory the actual combustion chamber was flycut a bit too to keep it at OEM specs.

Bottom line is, they are most likely stock. If 2.02's were added there is a chance the combustion chamber has not been altered. If they are the OEM 2.02's the combustion chamber should have minor alterations.

I know none of this helps if the heads are still on the engine. But, as I mentioned before, if they are on top of a 68 Corvette block, there is a very good chance they are 194's.

[Monte M.]

Re: 68 engine code ID problem

Calvin,

There has been one big thing missed here. Does the car have A/C?

Jeff, I am not sure why you brought up the "HT" as "HP" has been what he is asking about? Maybe a misspelling, or maybe there is something I am missing.

Calvin,, Jeff does make a good point though. Give us some more information to work with. First of all: is your vin number on the front pad of the block? What options does the car have? What does the engine look like?

A picture would go a long way. The more information we have, it makes it a lot easier to help you out.

[Calvin C.]

Re: 68 engine code ID problem

The heads are 291 1967 1.94. Sellers claims there were on engine with chrome stamped valve covers and the original air cleaner, I saw both they look original. But anyone can get original chrome valve covers. He believes the car is a 350 horse car. the engine pad is "V1201HD" Can't see pistons. Is "HP" a base engine car? He has air on the car now, I noticed that area where a over tank would be was drilled for one, but there is no room, did ac cars have a over flow.

[Jeff P.]

Re: 68 engine code ID problem

Calvin,on AC cars a vinyl bag replaced the aluminum overflow tank.

[Calvin C.]

Re: 68 engine code ID problem

I will try and get more info and pictures. Thanks. The guy has a lot of money in this car. The chassis is completely redone (nice) all brakes rear end and front end redone. By local qualified people. Looks like all mechanical has been gone thru. The soft top needs replacing, needs pipes, some body work and paint, seat covers and carpet. All else seems to be there in excellent shape. Trying to get it for 15k but really wanted the L79.

[William C.]

Re: 68 engine code ID problem

OK, 291 heads would be expected on a '68, 300HP version, What is the tach redline? What distributor part number 1111194 was 300 hp and 1111438 was the 350 hp version. Again, flatop or domed pistons should about nail it. Is the vin derivitive stamped on the pad? Match the VIN on the car? Should be easy to get to the bottom of...

[Jeff P.]

Re: 68 engine code ID problem

Here's two pics of an HT Survivor. L79 350 HPimage.jpgimage.jpg

[Calvin C.]

Re: 68 engine code ID problem

Vin matches the engine pad. The interior appears to be a air car. Can't see pistons.