[unruhjonny]

Originally Posted by Held for Ransom

More like 3".

Thank you for the correction, you made me look further into this, and it appears as though my memory was a bit fuzzy:

Originally Posted by Rocky Rotella

While many companies market exhaust extensions common to '74-75, and the two years do share a similar appearance, the '75 extension is definitely different than the '74 unit.

The attached photo illustrates the differences between the two. In addition to the lateral bends (which creates specific LH and RH extensions), the '75 unit was welded to the tailpipe and sold as an assembly where the '74 unit was a slip fit design and sold individually and fit both sides.

The one-year-only '75 extensions are certainly rare. They were limited to 400-powered Trans Am (455 cars had splitters) and I believe the '75 Formulas were equipped with them as well.

Originally Posted by Held for Ransom

Did you find a PN stamped where the exhaust pipe goes in?

You made me look closer;
Bottom to top these are:
- my car's original tips: if there was a number it's gone, I used a grinder to clean the end of the one which still has the neck
- 71.5-73 OE tips: 481525S1W ("W" appears to be weakly stamped)
- 71.5-73 OE tips: (no numbers)
- 1974 SR tips: GM495832FT (not on the neck; added for clarity)

Please notice that I have corrected myself - I thought that these were in fact 70-73 SR parts because they were pulled off of a 1973 Formula 455(M40) the better part of twenty years ago.

When I read last night that the 1974 tips were only three inches longer, I wondered to myself if they were actually 1974 parts.

After looking for part stampings, I took it a step further and pulled out an MPC, looked up group 3.705 (mentioned in the thread where Rocky's reply was taken from) and found the following:

2 - 481525 1970/8CYL - 4BC; 1971-73/ALL WITH FORMULA OR TRANS AM - DUAL EXHAUST
2 - 495832* 1974 DUAL EXHAUST
1 - 498164@ 1975/ALL WITH DUAL TAIL PIPES - RIGHT
1 - 498165@ 1975/ALL WITH DUAL TAIL PIPES - LEFT

* NEW PARTS REVISON #2
@NEW PARTS MASTER CAT.
(print date: November 1974)

Maybe some 70-73 cars appear to have longer tips because they are using the 1974 tips(?) - as this was the case with the 1973 Formula I pulled them from;
I wonder if the 1974 tips ever superseded the 70-73 tips?