1965 FI - HG vs. HN suffix code

[Edward M.]

There is a discussion on another Corvette Forum about the spacing between the letters of the HG or HN engine suffix code on a 1965 FI car.

One poster made this statement:

HG is an L84 with standard ignition and HN was an L84 with transistor ignition. Transistor ignition was an option on 65 L84 cars. When the L84 engines were built and stamped in Flint they did not know what ignition was going to be installed thus either the G or N was added later. Seems like a likely scenerio to me.

Does this make sense to NCRS? I do not own a 1965 judging manual, but I figure something like this wopuld be covered somewhere if it were true.

Thoughts?

[John D.]

Re: 1965 FI - HG vs. HN suffix code

Ed, Engine pads are not my forte. Looking on page 100-102 of the '65 manual I don't see anything about spacing that you mentioned. Now to wait for the gurus to chirp in. John

[Loren L.]

Re: 1965 FI - HG vs. HN suffix code

Contrary to the "gap" theory, it would appear that the engine line KNEW - from 6 possible stampings in 1962/3, the number jumps to 14 in 1964 and again jumps to 19 in 1965. For 1965 L79s, "HT" =d 4 spd, "HU" =d A/C + 4spd, "HV" =d TI + 4 spd and "HW" =d A/C, TI + 4spd. Somehow I would suspect a "jump" in the number of stampovers in 1964 & 1965.

[G B.]

Re: 1965 FI - HG vs. HN suffix code

The very few factory HG stamps I've seen have had a hand stamped "G" that was not part of the gang stamp. I don't know why. It's the same with the "L" in 1957 factory EL blocks. Frankly, I'm suspicious of any HG stamp that is perfectly aligned.

proto_opm_22_2.jpg

[Edward M.]

Re: 1965 FI - HG vs. HN suffix code

The very few factory HG stamps I've seen have had a hand stamped "G" that was not part of the gang stamp. I don't know why. It's the same with the "L" in 1957 factory EL blocks. Frankly, I'm suspicious of any HG stamp that is perfectly aligned.

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Jerry;

Is that a factory stamp? The pad surface just does not look right to me. The "brooch marks" are going sideways.

I have only seen one other HG stamp besides the one current being discussed, and it also had the G hand stamped.

This HG engine / car was discussed back in 2014 on this Forum.

Here is a link to that discussion:

https://www.forums.ncrs.org/showthre...hlight=HG+code

Ed

[Tim G.]

Re: 1965 FI - HG vs. HN suffix code

Those aren't broach marks, that a factory grind out to correct an error. That stamp looks great to me even though it's ground out.

[G B.]

Re: 1965 FI - HG vs. HN suffix code

Jerry;

Is that a factory stamp? The pad surface just does not look right to me. The "brooch marks" are going sideways.

I have only seen one other HG stamp besides the one current being discussed, and it also had the G hand stamped.

This HG engine / car was discussed back in 2014 on this Forum.

Here is a link to that discussion:

https://www.forums.ncrs.org/showthre...hlight=HG+code

Ed

The "sideways" marks are a factory grind-out. Those weren't supposed to happen either.

[Dave S.]

Re: 1965 FI - HG vs. HN suffix code

The very few factory HG stamps I've seen have had a hand stamped "G" that was not part of the gang stamp. I don't know why. It's the same with the "L" in 1957 factory EL blocks. Frankly, I'm suspicious of any HG stamp that is perfectly aligned.

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Gerry,
You are correct. The G in HG has been hand stamped on any examples I have seen.

[Edward M.]

Re: 1965 FI - HG vs. HN suffix code

The "sideways" marks are a factory grind-out. Those weren't supposed to happen either.

I see it now, thanks for pointing that out.

[Edward M.]

Re: 1965 FI - HG vs. HN suffix code

This is beginning to look like an serious research effort, with some of the work already done.

Project: Identify all Corvette engines from 1953 to 1982? where there is a gap / uneven spacing / misalignment of the last character in the engine suffix.

I see a list that looks something like this:

1957 283ci 283hp Engine code EL* - the 'L' character was stamped separately on ALL of these engines
1965 327ci 375hp Engine code HG** - the 'G' character was stamped separately on MANY of these engines.

*Actually, all 1957 Corvette engines COULD have this characteristic. So 1957 engine codes of EF, EG, EH, EL, EM, FG, FH, and FK could show an anomaly in the spacing of the last character. This characteristic appears to be more prevalent in earlier model year engines. So as production progressed in 1957, the stamping sequence went from 5 - 1 (Jan to Sep) or 6 - 1 (Oct to Dec) to 6 (Jan to Sep) or 7 (Oct to Dec) in a gang holder.

**Engine code HG is for 1965 Fuel Injected, Non-transistor ignition equipped engines. Engine code HN for 1965 Fuel Injected Transistor Ignition equipped engines does NOT have the spacing anomaly.

This would be an interesting project, and generate a great deal of discussion. That is a good thing.

[Michael G.]

[Edward M.]

Re: 1965 FI - HG vs. HN suffix code

I understand, and I meant to ask Mike if his 65 FI cars were HG or HN codes. Apparently this anomaly is not (or perhaps not as) prevalent on HN code engines.

I am also led to believe that HG code 65 FI cars are fairly rare, and that the majority of 65 FI cars also got the TI ignition.

Jim Gessner, can you elaborate on this?

Ed