1970 U-Clamp

[Stephen L.]

am i reading the TIM&JG wrong or is there a mistake?

the part in question is 70 AIM UPC8/A2 part 2 "clamp" - p/n 3848157 -

according to the tim&jg, 2006 (4th ed) at pg 99 there are 2 styles of clamps - open and enclosed

the part on my 70 is open - picture in the aim appears to be open style - but the tim&jg says "[a]n enclosed style carbon steel exhaust pipe clamp joins the header pipe and forward exhaust...."

is the clamp the tim&jg talks about the same part i mention above? - if so, it says enclosed but the aim and my car say open?

later in the same paragraph the tim&jg says that some 72's with 2.5" pipes (which this LT1 has) have been seen with open style clamps - but...this is a 70 and not a 72 - the clamps are definitely 2.5" as they have 2 1/2 stamped in one corner.

i am sure the tim and the aim and the car are all correct and due to my ignorance i am not making the right linkage - thoughts? - thanks, stephen

[Stephen L.]

Re: 1970 U-Clamp

here are some pics of the part off the car...




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[Stephen L.]

Re: 1970 U-Clamp

how do you post multiple pics???

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Stephen L.]

Re: 1970 U-Clamp *NM*

[Chuck S.]

Re: 1970 U-Clamp

Stephen, I suspect those are aftermarket clamps from an exhaust system replacement sometime in the car's life.

Typically, originality is not a concern for service shops...the clamps would not be reused because they may be heavily rusted, and will be difficult to re-install or simply snapped off (or burned off) in the removal; it's easier to simply replace rather than reuse, and aftermarket clamps are cheap.

One tip-off is the constant diameter of the U-bolt...original GM U-bolts had a flattened section at the top of the "U". But...I could wrong; remember what I told you: "Save EVERYTHING until you're done."

[Joe L.]

Re: 1970 U-Clamp

Stephen----

If you're asking if the clamp pictured is "correct", it's definitely not. There are several areas of "incorrectness". First, the configuration of the lower saddle is not like that originally used; it's similar to some clamps used, but not the same. Second, the u-bolts used at the junction of the forward and rear pipes had a "flattened" upper section; they were not completely round u-bolts. Third, the u-bolts appear to be 3/8" OD. All original clamps used 5/16" OD u-bolts.