427 radiator top core support plate

[Ronald L.]

In the 66 JG page 161 the big block top plate of the radiator mentions holes at approximately VIN 19000.

Do we know if that same flange could have been used "with no holes" for any radiators post late 1966? 67 - 68 & up big blocks?

[John H.]

Re: 427 radiator top core support plate

Do we know if that same flange could have been used "with no holes" for any radiators post late 1966? 67 - 68 & up big blocks?

Ron -

'67 big-blocks had the round holes.

[Ronald L.]

Re: 427 radiator top core support plate

John,

Would any of the service parts been less holes too?

Would auto tran or manual have made a difference?

Here I am refering to the top plate, same applies to the bottom core support?

[Ridge K.]

Re: 427 radiator top core support plate

John,

Would any of the service parts been less holes too?

Would auto tran or manual have made a difference?

Here I am refering to the top plate, same applies to the bottom core support?

Ron, I can't answer about '66s, or '68s, but I can tell you my very original no-hit bodied, 46,000 mile 1967 big block (April built) has the round holes. This car is four speed, L68 big block, no air conditioning. About 99% original.

I also own a service replacement '67 radiator core support that I believe was first sold over the parts counter in the early 1970s. It is 100% identical to the factory radiator core support in my car.
Same holes, same slight metal wrinkles, ..... an exact carbon copy.

I would take some pics for you, but we are having a downpour rain here today in northeastern Oklahoma.
Hope this helps.
Ridge.

[John H.]

Re: 427 radiator top core support plate

John,

Would any of the service parts been less holes too?

Would auto tran or manual have made a difference?

Here I am refering to the top plate, same applies to the bottom core support?

Ron -

I'm not familiar with the detail of the Service parts, but there's no vehicle functional reason for the round holes; they probably related to a manufacturing process at Harrison.

[Terry M.]

Re: 427 radiator top core support plate

Ron -

I'm not familiar with the detail of the Service parts, but there's no vehicle functional reason for the round holes; they probably related to a manufacturing process at Harrison.

By 1970 to 1972 we look for a square hole next to a rectangular hole -- and their function is to allow purchase for brackets that hold the radiator end tanks in place during transfer in the machinery that performs the soldering operation. For the 1970-72 radiators the purpose of those holes is exactly as John cites. I would expect the earlier and later holes serve a similar purpose -- of course there is always a chance that some engineer 40+ years ago said something along the lines of: "I'll give those judges something to look at long after I am gone!"

[Ronald L.]

Re: 427 radiator top core support plate

In a former life... yes all those holes have to do with core support through the furnaces as it proceeds through the assembly of the tubes and fins.

They usually get added when something does not stay square in the process.



OK, my late April radiator does not have the round holes on top. I have to verify the bottom tonight, don't recall them, but this time with pics. And this rad is now last remaining coolant system part that is old and or original. We know the part has not been out of the car back to 1977 ~ 75.

The issue is how in the world did an auto trans RH end tank get on this or in a 4-speed car?

If the part was replaced in 1975 or later it would have been a service replacement part that had these additional holes.

John, did you run out of manual BB rad's on April 28-9, 1966?

[Terry M.]

Re: 427 radiator top core support plate

I don't know about 1966, but for the early C3s there was a time when the one and only SERVICE REPLACEMENT radiator was equipped with an end tank for automatic transmission. The idea was if one didn't have an auto transmission one simply didn't use the cooler, and we should be happy to have a Harrison radiator rather than some POS made off-shore. Now we don't get any radiator from GM. :-(

[Joe L.]

Re: 427 radiator top core support plate

Ron, I can't answer about '66s, or '68s, but I can tell you my very original no-hit bodied, 46,000 mile 1967 big block (April built) has the round holes. This car is four speed, L68 big block, no air conditioning. About 99% original.

I also own a service replacement '67 radiator core support that I believe was first sold over the parts counter in the early 1970s. It is 100% identical to the factory radiator core support in my car.
Same holes, same slight metal wrinkles, ..... an exact carbon copy.

I would take some pics for you, but we are having a downpour rain here today in northeastern Oklahoma.
Hope this helps.
Ridge.

Ridge-----


That's how it is for virtually all SERVICE parts. If you obtain a SERVICE part at about the same time that the part was manufactured for PRODUCTION, the parts will be absolutely identical. This relationship may or may not continue throughout the SERVICE availability of the part, though, even if it continues to be available under the original part number. Features of the part not related to functionality may change over time for a variety of reasons.

Sometimes, even if the part number changes the parts will be identical, although this happens quite infrequently. A few cases that comes to mind, though, are the 1969-71 L-46 and LT-1 harmonic balancers and the 1969-71 base engine balancers. The original 1969-71 L-46 and LT-1 balancer was GM #3947712. The 1972 LT-1 (and 73-80 L-82) balancer was GM #6272224. This piece became SERVICE for 69-71 in July, 1972 and is absolutely identical to the 3947712.

The same goes for the 1969-71 base engine balancer, GM #3947704. This balancer was replaced by GM #6272222 also in July, 1972. The latter balancer may have been used for some or all 1972 base engine cars (although GM says it was not) and was SERVICE for 69-71 base engine cars. The 6272222 is still available from GM. I don't know how the current piece compares to the original 3947704 but I do know that for at least 20 years after 1972 the 3947704 and the 6272222 were absolutely identical.

Of course, there might be slight "tuning" differences between the above-referenced sets of balancers but there was certainly no difference in apparent configuration----no difference, at all.

[Ridge K.]

Re: 427 radiator top core support plate

Ridge-----


That's how it is for virtually all SERVICE parts. If you obtain a SERVICE part at about the same time that the part was manufactured for PRODUCTION, the parts will be absolutely identical. This relationship may or may not continue throughout the SERVICE availability of the part, though, even if it continues to be available under the original part number. Features of the part not related to functionality may change over time for a variety of reasons.

Sometimes, even if the part number changes the parts will be identical, although this happens quite infrequently. A few cases that comes to mind, though, are the 1969-71 L-46 and LT-1 harmonic balancers and the 1969-71 base engine balancers. The original 1969-71 L-46 and LT-1 balancer was GM #3947712. The 1972 LT-1 (and 73-80 L-82) balancer was GM #6272224. This piece became SERVICE for 69-71 in July, 1972 and is absolutely identical to the 3947712.

The same goes for the 1969-71 base engine balancer, GM #3947704. This balancer was replaced by GM #6272222 also in July, 1972. The latter balancer may have been used for some or all 1972 base engine cars (although GM says it was not) and was SERVICE for 69-71 base engine cars. The 6272222 is still available from GM. I don't know how the current piece compares to the original 3947704 but I do know that for at least 20 years after 1972 the 3947704 and the 6272222 were absolutely identical.

Of course, there might be slight "tuning" differences between the above-referenced sets of balancers but there was certainly no difference in apparent configuration----no difference, at all.

Joe, I really appreciate you taking the time to comment on this issue. I'll explain why.........I've seen far too many experienced "master level" judges comment on the TDB about NOS service replacement parts being "incorrect" in their words, and thus candidates for judging deductions.
I've bought, sold, traded, and studied these typical service replacement GM parts in NOS form for coming up on 40 years.
My conclusion is EXACTLY the same as yours,

I've asked this question before of those you seem to be "anti-NOS part".........Did Chevrolet build exactly 22,940 sets of parts for the 1967 Corvette model line,.......and then build the service replacement parts with different molds, machining, design, etc....? And did they build these service replacement parts at different manufacturing facilities.....? Did the suppliers build one series just for the assembly line cars, yet build different parts for those cars that needed service replacement parts, say within six months of their assembly line completion....?

And then for that urban-myth rumor that service replacement parts were sometimes "culls", with poorer chrome plating, etc........ Did Chevrolet have a huge, secret warehouse where parts went down a conveyor belt? Were their hundreds of employees sitting next to this conveyor belt knocking off the "cull" parts, or those with rougher plating jobs,........to be put in GM parts boxes, and then shipped to Chevy parts counters?

Were all the service replacement parts exactly identical to their assembly line counterparts...? No, of course there are some variations. AND, we could all agree that service replacement parts are sometimes "superseded" with an improved design. And then there are those design changes that after they occur, Chevrolet engineering will decide that the changed parts will become the official service replacement. The later design 1963 to 1982 power steering control valve would be a good example of this occurrence.
I just simply think it's a huge mistake for anyone judging to develop a preconceived notion that NOS service replacement parts are not as correct as assembly line installed parts. In fact, in many cases they are identical in every aspect. At least that's my conclusion after many decades of comparison research. Thanks, Joe.

Ridge

[Ronald L.]

Re: 427 radiator top core support plate

Ridge - commenting those service parts from experience, then and now.

No - not a line of workers sending the culls to service. Sort of can happen though while the part is a current model part in production. And the left over at model change over is usually directed that way.

Specifically about GM service parts, especially C2 Corvette circa the late 80's when the market for C2 parts began to heat up and they saw they could make big dollars on these parts. Let's take bumpers for example. The original tool was worn out, broke, scrapped melted for the steel... And all they were worried about was getting a quick part, yes the ripple and sandy chrome... They got someone to make another tool from the latest rev of the drawing, and make them cheap, what was a bumper costing at the dealer in 1988???

In this case the design was the same, quality probably less that the original parts.


In too many cases the part numbers were superceded time and time again so to say you have a NOS air cleaner for 1966 - completely wrong. To prove that we'd need to show you the revisions and how the part changed ---redrawn and redesigned - how many times have you seen that???

Sort of said NOS parts can't be all that good didn't I, well they were where the original part as released in 1963 or 4 for the C2 was the same part in 1967 and that same part number carried into the C3 - there are some good chassis parts that fit this category, and then there are those rear spring rubber cup retainers that changed and the NOS crowd call the later rev OK for C2 and they are dead wrong.

Or the guy selling NOS motor hooks for a C2 big block when there is photo evidence the Tonawanda motor was picked up by the carb studs, the parts never were in the AIM...hope that was not you either.

When I restored my first 66 427 in the 79-81 time period I got lots of parts directly from GM, but there were those times I'd go and expect to get an exact bolt and it had been replaced via a metric 'equivalent'. Wrong part - sorry! There is a land fill in Flint too for where these went after the 10 year service life...