[Bull]

Do any of you happen to know whether a '78 Lemans/Grand Lemans/Grand Am could be ordered from the factory with a dual exhaust system? If not true dual exhaust, then a y-pipe going into one catalytic converter, then splitting off into two outlets for the look of dual exhaust? Thanks for any help.

[Bull]

Do any of you happen to know whether a '78 Lemans/Grand Lemans/Grand Am could be ordered from the factory with a dual exhaust system? If not true dual exhaust, then a y-pipe going into one catalytic converter, then splitting off into two outlets for the look of dual exhaust? Thanks for any help.

[RandyW]

1980 is the only year I know of and then only on GP SJ and Grand AM.

[Bull]

Thanks for your response, Randy, you seem to be pretty knowledgable about these cars. Is there any reason that you can think of why I couldn't go to NAPA, order all the exhaust components for a 1980 Grand Am w/the dual outlets, and install them on my '78 Grand Lemans? What system do you have on your GA?

[RandyW]

I've got duals all the way back with Magnaflow mufflers. I put true duals on my car in Jan. 1980 and it's been that way since.
Since only a few were built including the Grand Prix SJ, I doubt those part numbers are available. But a lot of people are making the Buick GN system, the tailpipes were dead ringers and the muffler flows well.

[Maurice Hood]

Dave, I put dual exhaust on my 78 Grand LeMans and had to have the transmission cross member modified. If yours is like mine there is no hump in the cross member on the drivers side to accommodate the pipe. Mine are true duals with an X-pipe but I recently saw an article by Tom Hand showing a cross flow muffler and tailpipes for the second generation f-bodies that might fit the LeMans. Also, I-A makes a nice set of headers to fit your LeMans with a Pontiac engine. I hope this helps. Good luck.

[RandyW]

Mine has both pipes down the passenger side then seperate to the normal muffler positions and tailpipes.

[CraigGT37]

They didnt have duals from the factory till around 85", they had a single pipe from the converter to the muffler then dual pipes out.The GN's,442,Hurst/Olds and Monte Carlo SS had a "Y" pipe after the converter to dual mufflers and out,the converter had a rectangle outlet,so the "Y" would not be a direct replacement for the regular converter.
Craig

[RandyW]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by CraigGT37:
They didnt have duals from the factory till around 85", they had a single pipe from the converter to the muffler then dual pipes out.The GN's,442,Hurst/Olds and Monte Carlo SS had a "Y" pipe after the converter to dual mufflers and out,the converter had a rectangle outlet,so the "Y" would not be a direct replacement for the regular converter. Craig <HR></BLOCKQUOTE>

That's not correct, as early as 1978 El Camino's with 350 had dual outlets(I owned one new), also some V8 and Turbo G-bodies had dual outlets from 1979-on. All 1980 Grand Am and SJ Grand Prix's had dual outlets. Monte Carlo SS had twin resonators with dual tailpipes starting in '83. Turbo Buicks had dual tailpipes from about '82-on, some older 4 bbl versions had dual outlets.

[engineer]

what he asked about, is not available from the factory. There are no dual pipes from the convertor back to the muffler. there was a crossflow muffler with a single pipe from the convertor with dual tail pipes from the muffler on a 1980 GA. You could have gotten for a TA a dual pipe that mounted to the convertor to have two pipes out down one side of the driveshaft having a single hump trans cross member into two mufflers and two tailpipes, but not on a GA or Lemans.

[RandyW]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by engineer:
what he asked about, is not available from the factory. There are no dual pipes from the convertor back to the muffler. there was a crossflow muffler with a single pipe from the convertor with dual tail pipes from the muffler on a 1980 GA. You could have gotten for a TA a dual pipe that mounted to the convertor to have two pipes out down one side of the driveshaft having a single hump trans cross member into two mufflers and two tailpipes, but not on a GA or Lemans. <HR></BLOCKQUOTE>

He didn't exactly specify how it had to get to two tailpipes, I was offering the possible applications that would get him there. I'm well aware of what came on most any G-body Pontiac. I own an '80 Grand Am that I bought new!

The best system for look and sound, if you are going to keep the convertor is the Monte Carlo SS system with the y behind the CC going into 2 pipes with dual resonators.

[engineer]

I still have an 1980 GA since new.

[Pontiacdaver]

Hi guys, I'll throw in my 2 cents being both an owner, and having worked in both OEM Pontiac parts and aftermarket parts for the last 30 years. The original dual system, as engineer stated, was a single pipe from the cat. conv. to a sideways mounted dual outlet muffler. On my last G/A, a 79 4 speed I purchased from the original owner, I had the cat. conv. removed, a 2 1/4" pipe from the crossover to a V-Force (similar to Flowmaster)cross-mount muffler with 2 1/4" dual T/A split tips. The car, with it's anemic 301, ran as well as it would have with true duals, sounded awesome looked great, and didn't require any crossmember mods. Like so many other cars, Pontiac refined the 80 G/A to it's best version and then quit making it. Dave

[RandyW]

I wasn't arguing with him, mine was that way single to the muffler then dual out. But there were several variations on various G-bodies, starting as early as '78 on El Caminos.

[RandyW]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by engineer:
I still have an 1980 GA since new. </div></BLOCKQUOTE> Engineer, tell us about your G/A.

[Pontiacdaver]

Hi Randy, didn't mean to sound like I was siding against you, I think we are all saying the same thing, but with different words. I've seen a pic of your G/A.....absolutely beautiful.
And I agree.....tell us more about your 80 G/A engineer.

Dave

[RandyW]

Thanks for the props, I love these old cars!