1972 Lt1 w/press-in studs and 2.02/1.94 valves

[Terry M.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

The pictures I have are of a 6K mile set of 1972 LT1 heads. The valve springs are clearly painted orange, and the outline of the shape of the mask used for the exhaust ports and spark plug openings (the mask is all one piece) is clearly visible. What was supposed to happen didn't always happen -- are you surprised?

[Chuck S.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

The pictures I have are of a 6K mile set of 1972 LT1 heads. The valve springs are clearly painted orange, and the outline of the shape of the mask used for the exhaust ports and spark plug openings (the mask is all one piece) is clearly visible. What was supposed to happen didn't always happen -- are you surprised?

Not too surprised.

The fact that the edges of the mask have soft edges indicates something, like cardboard, was just laying there. I suppose Backyard Bubba could have used loosely positioned cardboard, but that seems like a factory masking trick that was used often. For certain, there doesn't appear to be any sharp edges indicating masking tape was used.

[Jerome P.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

Terry/Chuck/Joe and others

So what is your opinion; given all the above info, are they an original anomaly or heads rebuilt to the LT1 head standards?

[Terry M.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

The paint inside where the rocker covers usually would protect from paint means nothing.

The paint on your heads is too think, and the exhaust port area is not masked like the factory did -- at least not like they did on the set I have the unpostable pictures of. I don't think the paint job is factory.

As to whether that condemns the rest of the head as being non-original I don't know -- but it doesn't give me a lot of confidence that it is.

[Chuck S.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

Terry/Chuck/Joe and others

So what is your opinion; given all the above info, are they an original anomaly or heads rebuilt to the LT1 head standards?

Opinion: Original anomaly.

My 70 350/300/four should have had a 1108338 starter. It had a 1108418 starter dated about four weeks before production with no front support. Is it an original anomaly?...I'm convinced it's original and I'm not changing it. Anyone that's ever tried to locate a dated starter knows it's not easy to locate one that's just right. Further, the car had never been owned by anyone that cared about numbers correct restoration. Interesting fact: The NCRS spec guide lists the 1108418 for 70 350/MT engines, but indicates parenthetically that "usage unverified". I guess that means there has been one other properly dated example they couldn't eliminate as being a replacement.

With the same casting number being used on both the 200 and 255 hp engines, it would be interesting to know the head machining sequence; e.g. were heads stockpiled with studs already installed before the valve holes were finish machined? It would help to reason out why late 72 LT1 studs are found pressed in. For example...were heads with pressed in studs overproduced with no additional raw castings available? Were there other production schedule exigencies, etc.?

[Joe L.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

Opinion: Original anomaly.

My 70 350/300/four should have had a 1108338 starter. It had a 1108418 starter dated about four weeks before production with no front support. Is it an original anomaly?...I'm convinced it's original and I'm not changing it. Anyone that's ever tried to locate a dated starter knows it's not easy to locate one that's just right. Further, the car had never been owned by anyone that cared about numbers correct restoration. Interesting fact: The NCRS spec guide lists the 1108418 for 70 350/MT engines, but indicates parenthetically that "usage unverified". I guess that means there has been one other properly dated example they couldn't eliminate as being a replacement.

With the same casting number being used on both the 200 and 255 hp engines, it would be interesting to know the head machining sequence; e.g. were heads stockpiled with studs already installed before the valve holes were finish machined? It would help to reason out why late 72 LT1 studs are found pressed in. For example...were heads with pressed in studs overproduced with no additional raw castings available? Were there other production schedule exigencies, etc.?

Chuck------


A GM #1108338 and a GM #1108418 starter are essentially interchangeable. The only difference is that the 1108338 is a standard torque starter and the 1108418 is a high torque starter. So, an 1108418 could be used in place of any 1108338.

The 1108418 probably had very limited use on 69-70 Corvettes but it was used for many other Chevrolet applications, mostly for big blocks. I could easily see where a temporary shortage of 1108338 starters could have been accommodated by substituting the 1108418.

[John H.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

it would be interesting to know the head machining sequence; e.g. were heads stockpiled with studs already installed before the valve holes were finish machined?

Chuck -

I don't recall the way they managed this, but there were two different departments involved. The Head Machining Department had to mill the rocker stud bosses to a finish height dimension, drill and spotface the holes, then those eight holes had to be tapped 7/16"-14 for the screw-in stud threads. Then the Head Assembly Department had to install the guide plates and hex-base threaded studs in a single operation.

Since both the head machining transfer line and the automatic head assembly line had been in place for fifteen years, the above operations were most likely done as secondary operations, outside the main system; one doesn't tear into a fully-automated shuttle-transfer machining or assembly line that runs at 600 heads per hour and rearrange the rest of the department to add stations for a low-volume feature.

Engineering would have to authorize substituting press-in studs and deleting the guide plates, and I think that would be unlikely on a premium solid-lifter engine.

[Chuck S.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

Chuck------


A GM #1108338 and a GM #1108418 starter are essentially interchangeable. The only difference is that the 1108338 is a standard torque starter and the 1108418 is a high torque starter. So, an 1108418 could be used in place of any 1108338.

The 1108418 probably had very limited use on 69-70 Corvettes but it was used for many other Chevrolet applications, mostly for big blocks. I could easily see where a temporary shortage of 1108338 starters could have been accommodated by substituting the 1108418.

Thanks for that, Joe...I guess I don't have to worry about that starter spooling up the Mouse Motor.

The fun starts when/if it gets to the judging field; I can already see the deduct for no front starter support and my futile protestations. The front support requires a special upper casing through bolt with a stud end...my starter never had one.

It seems like I did some research on the starter back when I first learned of the discrepancy. I seem to recall the 1108418 was used on Camaro and Chevelle big block engines (). I didn't even remember it being listed in the spec guide and the "(usage unverified)" comment until now, which might indicate my current spec guide was updated AFTER my research.

[Joe L.]

Re: 1972 Lt1 w/press-in studs and 2.02/1.94 valves

Thanks for that, Joe...I guess I don't have to worry about that starter spooling up the Mouse Motor.

The fun starts when/if it gets to the judging field; I can already see the deduct for no front starter support and my futile protestations. The front support requires a special upper casing through bolt with a stud end...my starter never had one.

It seems like I did some research on the starter back when I first learned of the discrepancy. I seem to recall the 1108418 was used on Camaro and Chevelle big block engines (). I didn't even remember it being listed in the spec guide and the "(usage unverified)" comment until now, which might indicate my current spec guide was updated AFTER my research.

Chuck------


Personally, whether it was original, or not, I would add that long starter bolt with the extension and add the front brace. In fact, I would add it even if there was a judging penalty for it and, in this case, it sounds like it would be a judging advantage.