EGR Hold Down

[George W.]

I am looking for a picture of the stamped steel bracket that holds the EGR valve on the intake manifold. It is for a 1973 454, 4 speed car. I am not sure if the bracket for the small block and big black is the same or different. If some one could post a picture of this bracket it would certainly help in my search for this part.

Thanks

George

[Michael W.]

Re: EGR Hold Down

I'm sure Paul Latour will have a pic from his '74. AFAIK, small block and BB are the same set up.

[Joe L.]

Re: EGR Hold Down

I am looking for a picture of the stamped steel bracket that holds the EGR valve on the intake manifold. It is for a 1973 454, 4 speed car. I am not sure if the bracket for the small block and big black is the same or different. If some one could post a picture of this bracket it would certainly help in my search for this part.

Thanks

George

George-----


The EGR hold-down clamps (brackets) were different for small block and big block. They are the same, basic configuration, but different. As I recall, the big block bracket is slightly larger. The one you're looking for is GM #353087, but it was discontinued without supercession in December, 1981.

These brackets were only used for 73-74 applications. However, they were not unique to Corvettes.

[Paul L.]

Re: EGR Hold Down

George,

Referring to Joe's comments, I did not know the SB and BB clamps are different. But just as an illustration of what the SB/350 unit unit looks like here it is (actually I have several so I have showed top and bottom). I can only speculate but suspect the difference is in the "grip tip" on intake configuration. The snugging down on the intake channel after clawing on the EGR may differ.

As I said in another thread, it is a strange setup.

(Click to enlarge.)

[Harmon C.]

Re: EGR Hold Down

I think the clamp is the same on all engines. If their is a difference I never noticed it and have traded a few with no problems to big block customers.

[Paul L.]

Re: EGR Hold Down

I think the clamp is the same on all engines. If their is a difference I never noticed it and have traded a few with no problems to big block customers.

If so, and it works for him, George can have one courtesy of me. FOC (free of charge). But do verify application as per Joe Lucia before I commit.

[George W.]

Re: EGR Hold Down

Thank you all for your replies. This gives me the information I need. Paul, thanks for the offer on the clamp. I have been offered one from another person but if that falls through I will contact you.

George Walker

[Paul L.]

Re: EGR Hold Down

Thank you all for your replies. This gives me the information I need. Paul, thanks for the offer on the clamp. I have been offered one from another person but if that falls through I will contact you.

George Walker

No problem, Just let me know by PM.

[William M.]

Re: EGR Hold Down

My '73 LS4:


Just don't paint it orange or Lyle will deduct points

[Joe L.]

Re: EGR Hold Down

I think the clamp is the same on all engines. If their is a difference I never noticed it and have traded a few with no problems to big block customers.

Lyle-----


There was a difference but, apparently, it's pretty subtle. The small block clamp was GM #353090 and the big block clamp was GM #353087. The difference in part numbers almost assuredly means that there was some difference. Also, neither of these ever superceded the other for SERVICE. They were each discontinued without supercsession in the 1985 and 1981, respectively.

I obtained what are reported to me to be one of each. The fellow I got these from is in a position to know the differences. Still, I question whether I really have one of each or whether these are both the small block clamps. Unfortunately, there is no GM part number on either and there is no GM parts tag on either. So, it's difficult to identify them with certainty.

In any event, the black-painted clamp pictured in the photo is supposed to be an NOS GM piece and a small block clamp. The natural steel piece is supposed to be an original big block clamp. However, it's possible that the fellow that provided them might have the applications reversed.

The main difference I see between them is the configuration of the "tab" on the small end of the clamps. It's possible that this was a designed-in feature which differed for small blocks and big blocks but I cannot understand why. In my opinion, it's also possible that the difference in the tab could be a result of different tooling or tooling wear.

Does anyone have a KNOWN big block clamp off the car that they could provide a series of detailed photos of from several angles?

[Harmon C.]

Re: EGR Hold Down

The clamp I have seen installed on original cars was a gray-black phosphate and not painted. As you said any difference is less than the pictures show.

[Todd L.]

Re: EGR Hold Down

When I get home, I will take a picture of the clamp used on my 74 LS4. How do you get a gray-black phosphate finish?

Todd

[Joe L.]

Re: EGR Hold Down

When I get home, I will take a picture of the clamp used on my 74 LS4. How do you get a gray-black phosphate finish?

Todd

Todd------


You can have it done by a plater (which will be expensive unless you have a lot of other parts to do with it) or you can get a home plating kit from sources like Caswell or Eastwood.

I'll look forward to the photos of the clamp.