NOS Muffler Question

[Rick N.]

I have a pair of NOS Mufflers Part #'s 3943385 and 3943386 I'm using for a '70 LS5.

After removing the hanger brackets that aren't needed for a 68-72, I noticed that the muffler case seam is facing the quarter panel instead of the spare tire carrier.

I didn't notice this before I bought them.

Were all the NOS mufflers made this way?

How is this seam going to effect judging?

Thanks, Rick

[Gary B.]

Re: NOS Muffler Question

Not all NOS mufflers were made this way, but a batch did. I have seen some.

If I was judging, you would get a 20% configuration. If you remove the numbers and date, they and/or I could not tell when they were made. If left on, then another 20% for date could be deducted. If you don't butt weld them to the center pipes, then 20% for installation. CDCIF.
8 Originality, 7 Condition; for mufflers, so you could loose as much as 60% of 8 points. Or, 5 points?

If you bought reproduction "aluminized" mufflers, it's 25% because of standard deduct table. So, 2-points. A judge might ignore the Std. Deduct and still apply CDCIF. They do occasionally on mine. No hard rules in place. But repo mufflers do have the seam in the right place, aluminized pipes on the inlet and outlet.

I would use the GM mufflers, remove the numbers and date, butt-weld them on. Minimal point deduction and they will sound better. Original GM mufflers sound different than repo's, I don't care what they say :-)

Gary B

[Rick N.]

Re: NOS Muffler Question

Hi Gary,
Thanks for the reply.
I had planned on butt welding them.

Since the date code is embossed, how would I go about removing it?
Have any suggestions?

BTW... Should I get rid of the GM logo and the W as well ?

Thanks, Rick