68-72 exhaust part numbers?

[Brad M.]

I was wondering if someone could provide some info on some exhaust part numbers for 68-72. These are on the auction site and supposedly from a 68 327 4speed car.
Most of the numbers seem different from the ones that I am familiar with as correct for 70-72 Lt-1, etc.
The front pipes are 334925 and 334940 - the '925 is consistent with what I expected, is the 334940 for an automatic?

The mid pipes apparently have numbers ending in '659 and '660 - full part numbers not available. (as compared to 3931829 and 39331830 which I believe to be correct for 70-72 lt-1 and BB). Any idea what the differences are? (are these again for automatic).

The mufflers are supposedly GM and have 21588 and 21589 on them (as compared to the 3944385 and 3944386). I am probably more just curious what these items are and how they are different from the ones that I am familiar with - Anyone know?

[Joe L.]

Re: 68-72 exhaust part numbers?

I was wondering if someone could provide some info on some exhaust part numbers for 68-72. These are on the auction site and supposedly from a 68 327 4speed car.
Most of the numbers seem different from the ones that I am familiar with as correct for 70-72 Lt-1, etc.
The front pipes are 334925 and 334940 - the '925 is consistent with what I expected, is the 334940 for an automatic?

The mid pipes apparently have numbers ending in '659 and '660 - full part numbers not available. (as compared to 3931829 and 39331830 which I believe to be correct for 70-72 lt-1 and BB). Any idea what the differences are? (are these again for automatic).

The mufflers are supposedly GM and have 21588 and 21589 on them (as compared to the 3944385 and 3944386). I am probably more just curious what these items are and how they are different from the ones that I am familiar with - Anyone know?

Brad-----


GM #334925 is a 2-1/2" left front exhaust pipe for Corvette small blocks first used in PRODUCTION for the 1973 model year. It became SERVICE for 68-72 when the original pipe was discontinued. It is 100% functional for 68-72 applications but is configured slightly different.

The GM #334940 is same as above except for the RIGHT side of 73-74 with small block AND THM-400 transmission. It is also SERVICE for 68-72.

The only exhaust-related components I can find with the last 3 digits '659' and '660' are GM #3974659 and 3974670. These are the muffler extensions (tips) used for 70-72 Corvettes.

GM SERVICE mufflers have various number embossments. I have some known NOS 3943385 and 3943396 that have no embossments on them. Some of the others I have do have embossments, but I'm not going to dig them out now. By the way, though, ALL GM #3933485 and 3943386 mufflers have DUAL BRACKETS. Some aftermarket do, too, of course.

[Brad M.]

Re: 68-72 exhaust part numbers?

Thanks Joe.