70 LT1 pad

[Paul O.]

Re: 70 LT1 pad

Jerome broach marks are front to back as viewed from the front of the car. If you go back and view the 2 photos I posted the one with the VIN look at the area just in front of the head and you will see some broach marks.

A factory grind out is when there was a mistake made in the stamping and the worker would remove the stamping and then re-stamp the block. In the photo I posted we believe this block had a problem after assembly and went back to the repair shop. Was disassembled and the block was reused. This would have been at the Flint plant. If the error occurred in St. Louis only the VIN would have been ground out and redone. We think the Flint worker was a little over zealous in his grind out of this block but he did what he was told to do remove the stamping for a re-stamp.

Paul 18046

[Jerome P.]

Re: 70 LT1 pad

Thanks Paul.

That's what I thought - front to back. The broach marks above the s/n are almost non-existent, but there.

The left to right marks in both pictures; are they the result of the factory grind out?

[Paul O.]

Re: 70 LT1 pad

Jerome yes they are.

Paul 18046

[Dave S.]

Re: 70 LT1 pad

Jerome yes they are.

Paul 18046

Paul,
My LT-1 block was stamped V0702CTK so it was done 5 days before the example given. It is a much more consistent stamp than the one shown. The CTK was part of a gang stamp.

[Jerome P.]

Re: 70 LT1 pad

Paul,
My LT-1 block was stamped V0702CTK so it was done 5 days before the example given. It is a much more consistent stamp than the one shown. The CTK was part of a gang stamp.

Dave, it would be interesting to see a picture of your pad - for comparison. If you have one and it is not a lot of trouble.

[Paul O.]

Re: 70 LT1 pad

Dave the original start of the thread was about the stamp pad that John McRae posted. The photo I posted for John was a car we had judged in Knoxville and I asked the owner if he could send me detailed photos. There are a lot of similarities of the Flint stamping that were done on the same day. The other interesting item that day in Knoxville in the judging school we had stamp pad photos. There was one for a very early 71 pad it was also a Flint grind out. The markings from the grind out were almost identical between the 2 pads.

I just think that the Suffix and date alignment and misalignment are very similar and would help John make an informed decision about the car he was looking at.

Paul 18046

[Dave S.]

Re: 70 LT1 pad

Dave the original start of the thread was about the stamp pad that John McRae posted. The photo I posted for John was a car we had judged in Knoxville and I asked the owner if he could send me detailed photos. There are a lot of similarities of the Flint stamping that were done on the same day. The other interesting item that day in Knoxville in the judging school we had stamp pad photos. There was one for a very early 71 pad it was also a Flint grind out. The markings from the grind out were almost identical between the 2 pads.

I just think that the Suffix and date alignment and misalignment are very similar and would help John make an informed decision about the car he was looking at.

Paul 18046

Paul,
The original pad photo was not very good so we could not see any real broach so we have no way to analyze that. My thought was that my stamp which was 5 days later was done with a gang holder so why was an Flint assembly re-stamp done 5 days earlier not done that way.????

[Paul O.]

Re: 70 LT1 pad

Dave we could only make a some what educated guess here. When I judged the pad we had a lot of issues but with the help of many other judges. Stan F, Terry M., John B. and others. The photos of the other stamp pads that evening was also a great help.

After the smoke had cleared the consensus was that this was a late 70 production and the Flint plant was also starting 71 LT-1 production. They need more 70 LT-1 engines and were reciving blocks from the repair shop. So that's why the grind out. As for the stamping alignment that maybe the way on that particular day the gang lined up. Also the worker that is installing the stamp on a grind out block would really have to do a very heavy hit and most likely several of them which would cause some other changes. But we are just trying to make a some what educated decision.

We maybe wrong but the stampings that were done the same day for me look the same. The layout of the stamp, the round 0 and the elliptical 0 in
the date just lead me down that road.

Paul 18046

[Dave S.]

Re: 70 LT1 pad

Dave we could only make a some what educated guess here. When I judged the pad we had a lot of issues but with the help of many other judges. Stan F, Terry M., John B. and others. The photos of the other stamp pads that evening was also a great help.

After the smoke had cleared the consensus was that this was a late 70 production and the Flint plant was also starting 71 LT-1 production. They need more 70 LT-1 engines and were reciving blocks from the repair shop. So that's why the grind out. As for the stamping alignment that maybe the way on that particular day the gang lined up. Also the worker that is installing the stamp on a grind out block would really have to do a very heavy hit and most likely several of them which would cause some other changes. But we are just trying to make a some what educated decision.

We maybe wrong but the stampings that were done the same day for me look the same. The layout of the stamp, the round 0 and the elliptical 0 in
the date just lead me down that road.

Paul 18046

Paul,
Everything you say makes sense to me. Trying to offer other points of fact to consider. My 0702CTK pad has a third style of "O" as well. Grind outs certainally may have used a different stamp technique.

[John H.]

Re: 70 LT1 pad

Most engine plant suffix conversions (to create one configuration from another due to shortages, bad forecasts, etc.) were fairly simple swaps of external bolt-on items, and were done either in a repair area or with engines already in a shipping rack, and were restamped with entirely different tools than the gang-holder used on the main assembly line, so it's unlikely that there would be any similarity between a grind-out restamp done off-line and a main line production stamp.

[Dave S.]

Re: 70 LT1 pad

Most engine plant suffix conversions (to create one configuration from another due to shortages, bad forecasts, etc.) were fairly simple swaps of external bolt-on items, and were done either in a repair area or with engines already in a shipping rack, and were restamped with entirely different tools than the gang-holder used on the main assembly line, so it's unlikely that there would be any similarity between a grind-out restamp done off-line and a main line production stamp.

John,
Would that hold true for an LT-1 motor where the internal components were unique to an LT-1 engine.

[John H.]

Re: 70 LT1 pad

John,
Would that hold true for an LT-1 motor where the internal components were unique to an LT-1 engine.

Dave -

The LT-1 engine as-shipped in the '70 Corvette and Camaro Z/28 were the same engine except for the exhaust manifolds and distributor calibration; that would be a simple conversion.