1969 427 thermostat housing question

[Bill N.]

I'm looking for an OEM or NOS housing to replace a reproduction on my '69 427/390. I've got the part number but I'm wondering if the housings were date coded. I'd appreciate any information. Thanks!

[Joe L.]

Re: 1969 427 thermostat housing question

I'm looking for an OEM or NOS housing to replace a reproduction on my '69 427/390. I've got the part number but I'm wondering if the housings were date coded. I'd appreciate any information. Thanks!

Bill------


I don't think that any of the original GM #3877660 thermostat housings had any sort of date code. Some of the later SERVICE examples have some embossments that some might regard as a date code but I do not think they are such.

[Bill N.]

Re: 1969 427 thermostat housing question

Hi Joe,

Thanks for the info. Mine currently doesn't have any embossing except for the part number on top, not on the flange. I know it was replaced in 2000 according to invoices that came with the car. I'm sure it was replaced with a reproduction. The cost of the replacement was only $20 back then. I do want things to be correct but I'm wondering if the NOS examples online are service replacements vs. the real deal. Here's what I've found: http://www.ebay.com/itm/NOS-66-67-68...p2054897.l4275

Bill

[Joe L.]

Re: 1969 427 thermostat housing question

Hi Joe,

Thanks for the info. Mine currently doesn't have any embossing except for the part number on top, not on the flange. I know it was replaced in 2000 according to invoices that came with the car. I'm sure it was replaced with a reproduction. The cost of the replacement was only $20 back then. I do want things to be correct but I'm wondering if the NOS examples online are service replacements vs. the real deal. Here's what I've found: http://www.ebay.com/itm/NOS-66-67-68...p2054897.l4275

Bill

Bill------


Although I can't see all of it in the photo, I can see enough of it to be pretty sure this is a later GM SERVICE piece. It's not configured like the 3877660 housing circa 1969. It's possible that this configuration was used in PRODUCTION for later C3's but not for 1969.

[Bill N.]

Re: 1969 427 thermostat housing question

Thank you, Joe. This is what I need to know. I'll pass on it and keep looking. i appreciate the help. If you could send me to someone you know of I'd appreciate that, too!

[Peter S.]

Re: 1969 427 thermostat housing question

Hi Bill,

This one looks pretty nice: http://www.ebay.com/itm/1966-74-CHEV...59553b&vxp=mtr

The 660 was used on alot of motors, you shouldn't have much of a problem finding a good, original example.

[Joe L.]

Re: 1969 427 thermostat housing question

Thank you, Joe. This is what I need to know. I'll pass on it and keep looking. i appreciate the help. If you could send me to someone you know of I'd appreciate that, too!

Bill------


One word of caution: many judges consider that all big blocks had the part number of the thermostat housing on the flange rather than the neck. I don't believe that. It may well be that many or, even, most big blocks used a thermostat housing with the part number on the flange but I really don't think that ALL were that way. In any event, to be "safe" from what I believe is a misconception, you might want to find a 3877660 with the part number on the flange. The problem is that because of this big block-related misconception, these housings usually sell for much more money. Nevertheless, if yo look for awhile, you should be able to find one at a reasonable price. These things are anything but rare.

[John H.]

Re: 1969 427 thermostat housing question

The GM drawing for the 660 thermostat housing leaves the choice of the part number location to the supplier/manufacturer; they could put the number anywhere they liked as long as it could be inspected.

[Peter S.]

Re: 1969 427 thermostat housing question

The GM drawing for the 660 thermostat housing leaves the choice of the part number location to the supplier/manufacturer; they could put the number anywhere they liked as long as it could be inspected.

Hi John,

Do you have a copy of that drawing that you are willing to share? It has seemed (and I have absolutely no scientific evidence to back this up) that the part number location varied based off of casting date rather than big block vs. small block?

[John H.]

Re: 1969 427 thermostat housing question

Hi John,

Do you have a copy of that drawing that you are willing to share? It has seemed (and I have absolutely no scientific evidence to back this up) that the part number location varied based off of casting date rather than big block vs. small block?

Hi, Peter -

See 660 drawing below, with notation at the bottom for "optional" location of manufacturer's ID. The manufacturer of the 660 housing had no clue what the final application would be - he just shipped "X" number to each engine plant. If you need a much higher resolution drawing, I can supply it.


660Housing (2).jpg

[Peter S.]

Re: 1969 427 thermostat housing question

Hi, Peter -

See 660 drawing below, with notation at the bottom for "optional" location of manufacturer's ID. The manufacturer of the 660 housing had no clue what the final application would be - he just shipped "X" number to each engine plant. If you need a much higher resolution drawing, I can supply it.


[ATTACH=CONFIG]60424[/ATTACH]

Thanks John! Another question for you and/or Joe: Who creates/designs the part? Is that a GM drawing which gets sent out to a fabricator?

Lastly, I assume the triangle with the "ADC" is the manufacturer's mark. Were there multiple manufacturer's because I have seen housings without (at least to my inspection) any manufacturer's mark.

[Joe L.]

Re: 1969 427 thermostat housing question

Thanks John! Another question for you and/or Joe: Who creates/designs the part? Is that a GM drawing which gets sent out to a fabricator?

Lastly, I assume the triangle with the "ADC" is the manufacturer's mark. Were there multiple manufacturer's because I have seen housings without (at least to my inspection) any manufacturer's mark.

Peter-------


A part and drawing like this one was designed and drawn by GM. The parts manufacturer had to manufacture a part which conformed to the drawing and specs.

There were almost certainly at least two manufacturers of this part. Most GM part drawings require that a manufacturer's ID appear on the part. However, I've seen quite a few parts over the years that didn't appear to have a manufacturer's ID on them. Usually, I think that parts manufactured by internal GM parts manufacturing operations of the day didn't either require or receive manufacturer's ID. But, I've seen parts that I highly doubt were manufactured by internal GM operations that did not have manufacturer;s ID's on them.

[Peter S.]

Re: 1969 427 thermostat housing question

Joe and John--

Thank you both. Your knowledge is enlightening, thank you for sharing.