1973 Survivor (?) engine I.D.

[Don B.]

I have to start out saying thanks to the NCRS organization as a whole. All my life (I'm 66 now) I've assumed my desire to restore cars was an affliction ... as an NCRS member, I now realize it's actually a passion, and shared by many.

Having received my library of NCRS books (basically everything available re: a 1973 Vette) and my Shipping Data report, I've confirmed some of the verbal legend (myth?) that came with the car. Namely, how a 46 y/o rust free California car could possibly end up on Michigan's Upper Peninsula (UP I understand the locals call it) for me to buy and ship back to California.

My question today is engine ID ... it's a J code car (5th digit of the VIN), and the casting numbers (back of the block left/right over the bellhousing flange) are appropriate. But the stamp pad (flat machined pad in front of the the right cylinder head) looks nothing like whats shown in the TIM/JG. Why is the shape wrong, and why is it scratched, and why do I see "T030" (barely visible stamp on the left of my photo, perpendicular the the usual stamp orientation).

I have lots of pics, but understand I'm limited to 4 here in the forums ... so here they are. FYI, the full VIN is 1Z37J3S418224, and the transmission is stamped 13S418224. All the other casting codes I can find (heads & manifolds) are appropriate for an unmolested car, using the TIM/JG as a guide.

Thanks for your help!

Don Becker

[Tom R.]

Re: 1973 Survivor (?) engine I.D.

What I'm seeing off hand, is a stamp pad configuration typical of a late model C3 engine. The photo attached shows a 1978 stamp pad. It appears the engine has been changed while the original transmission remains.

[James G.]

Re: 1973 Survivor (?) engine I.D.

It would be odd for a Tonawwanda assembled engine to have the oil galley plug at the front of the block... the plug is a result of the machining operations at FLINT.

[Robert G.]

[Russ S.]

Re: 1973 Survivor (?) engine I.D.

Are you sure that casting date isn't a 8 instead of a 3?

[Joe L.]

Re: 1973 Survivor (?) engine I.D.

Are you sure that casting date isn't a 8 instead of a 3?

Russ------


I think it's clearly an "8" and that would be consistent with the configuration of the stamp pad. Everything considered, I would opine that this is a SERVICE block.

[Don B.]

Re: 1973 Survivor (?) engine I.D.

Joe, I reread the TIM/JG re: casting codes & stamps. I don't see any mention of a "service" block. Which leads me to ask ... what is a service block?

[Joe L.]

Re: 1973 Survivor (?) engine I.D.

Joe, I reread the TIM/JG re: casting codes & stamps. I don't see any mention of a "service" block. Which leads me to ask ... what is a service block?

Don-------


Any SERVICE part is a part supplied through a GM dealer (or, other dealer) parts department to replace a part originally installed on a vehicle. In the case of a block, a SERVICE block will have, among other possible differences, no stampings on the engine stamp pad.

[Don B.]

Re: 1973 Survivor (?) engine I.D.

Thank you for the suggestion Brett ... I assume we're trying to bring out any letters (stamps) that may be hiding. Here's a pic after two brushings with Crest (Vicki wouldn't let me use the electric toothbrush, so my arm strength was a limiting factor. This pic represents about ten minutes of scrubbing).


You mention that a service block has no stamps ... so does the "T030" mean this is just some generic Chevy block? Tom was kind enough to send a pic of a late-model C3 stamp (see earlier in this thread), and while my pad shape matches, I don't see any numbers (aside from the wrongly oriented T030), even when I try to look thru the scratches.


I also tried to bring out the casting date code, but even after removing the right-side ignition shielding and plug wires my photos aren't any better than before. Moving the light around, it looks to me like (pan head screw-looking casting symbol, capital M, big space, 28, (pan head screw-looking casting symbol).


My other pics today are of the head casting #'s as seen through the oil filler opening (thanks to my TIM/JG for that tip), and the transmission stamp (which I realize is irrelevant to establishing engine authenticity).

[Robert G.]

[Don B.]

Re: 1973 Survivor (?) engine I.D.

The VIN is a J code (5th digit). So I believe that means base L48.

[Robert G.]

Re: 1973 Survivor (?) engine I.D.

The VIN is a J code (5th digit). So I believe that means base L48.

[Joe L.]

Re: 1973 Survivor (?) engine I.D.

Thank you for the suggestion Brett ... I assume we're trying to bring out any letters (stamps) that may be hiding. Here's a pic after two brushings with Crest (Vicki wouldn't let me use the electric toothbrush, so my arm strength was a limiting factor. This pic represents about ten minutes of scrubbing).


You mention that a service block has no stamps ... so does the "T030" mean this is just some generic Chevy block? Tom was kind enough to send a pic of a late-model C3 stamp (see earlier in this thread), and while my pad shape matches, I don't see any numbers (aside from the wrongly oriented T030), even when I try to look thru the scratches.


I also tried to bring out the casting date code, but even after removing the right-side ignition shielding and plug wires my photos aren't any better than before. Moving the light around, it looks to me like (pan head screw-looking casting symbol, capital M, big space, 28, (pan head screw-looking casting symbol).


My other pics today are of the head casting #'s as seen through the oil filler opening (thanks to my TIM/JG for that tip), and the transmission stamp (which I realize is irrelevant to establishing engine authenticity).

Don-------

I do not know what the "T030" stamping denotes. The "T" may denote the Tonawanda engine plant or it may indicate something else. It really does not matter. There is really no doubt that this is a replacement block. First of all, as Tom mentions this configuration stamp pad was used in later C3 production and definitely not as early as 1973. As a matter of fact, it so happens that I purchased a new Chevrolet short block in 1975 with a 1975 casting date. That block has the earlier style, long stamp pad. So, I would say there is no way that your casting year is 1973 and is, in fact, 1978. This is what it appears to me to be and by that time the "short" stamp pad was being used for small blocks. So, the "short" stamp pad and 1978 casting year are consistent.

I'd say that the cylinder heads could very well be original to the car assuming that the date works. I can't confirm because I'm away from home and have no references available.

What likely occurred is that some sort of engine problem occurred sometime after 1978 and required the replacement of the short block. It's virtually certain that this block did not originate from some other car inasmuch as there is no evidence of expected traditional stampings seen on the stamp pad.