gonna cut a hole in each frame rail of my 60 catalina (x frame car) so i can run the exhaust through it. holes will be up front just behind the body mount. it's gotta be done like this cause when the car is laid out, the exhaust it the lowest point. and no, wont be able to route it any other way. idler arm, etc are in the way. anyway, the frame rail is 6"x3". how big of a hole will be safe. these will be sleeved of course. i've got some 3.5", and some 4.5". both are on the large side of 1/8 thick. is this gonna be strong enough? the bigger diameter is nice cause it gives us more room to work with, but i worry about structural integrity. any ideas, tips, pictures, etc? am i out of my mind? tell me now before i start cutting!!!
Tubes, of wall thickness equal or greater to that of the frame, welded in the holes cut, will actually increase rigidity.
Exactly what B29 said.....Use mild steel tubing, not the aluminized exhaust tubing, weld both sides all the way around and you'll be good to go Pat
I'll "chime in"... I'd run it the way Pontiac did. Most all the X frame GM cars from this period had dual exhaust available. I'm not a Pontiac expert so you might need manifolds designed for dual exhaust. That I can't answer. I've been doing exhaust for 30 years and never cut a hole in an X frame GM car. I've cut a lot of holes in crossmembers in ladder type frames and never thought anything of it but in an X frame GM frame my gut reaction would be that it's not a good idea. Especially when I don't think it's necessary. Just my worthless opinon.
Not trying to belittle you or anything, but I'm assuming when he says "laid out", he's talking about putting it on the ground with the help of air bags, or maybe hydraulics. I would also assume, that when he does that, the exhaust would be scraping/laying on the ground, if it were run through the factory locations for the exhaust. Anyway, as B29 said, as long as you use the good shit, and weld it sufficiently, all will be good. -Aaron
Oh you mean you guys lower your cars??? No offense taken. When done right the bottom of the frame is the lowest point. This doesn't mean that the muffler will never catch and get yanked off. It does mean that going through the frame won't get the muffler any higher...the floor pan is the limiting factor for each way you do it. I usually make an angled brace for the muffler inlet. It lets the muffler ride up and over the obstuction. It doesn't always work but it helps. The original mufflers were very thin for these cars. A bullet style glasspack or straight pipes is also an option. If you use heavy wall tubing for the opening it will probably be OK. It just seems like a lot of unnecessary work to me.
It seems funny to me that you are saying "X" frame Pontiac....Is this a Canadian car?...........same frame as a Chevy Impala? These are lowered all the time, shouldn't have to go through the frame..........unless you are doing something strange with the exhaust.
it's 60 catalina. has an x frame. not a canadian model. not running mufflers. straight out the back. i'll take pics when done and show ya'll what i'm dealing with. holes are cut, tubing cut, ready to be welded in. then bend new exhaust.
Learn something new every day...was not aware that the Pontiacs had "X" frames...Didn't believe you, so I researched it. I guess they used them until 61 or 62. I know the 62 Catalinas had a perimeter frame. My 62 Canadian Pontiac has the "X" frame, same as Impalas. The headers come out the side and the mufflers are right under the driver........I figure you want to come straight back and through the frame. Would appreciate some pictures, as I might think about that myself.
Over the years, I've dualed half a dozen '60 Pontiacs, never had any problem hiding everything under the car in the space provided from the factory ... 302
well, the work is done. holes were cut, and then sleeved. new exhaust was run. this might need a little tweaking, as we were running out of time. but maybe not. drove it home, sounds fine, no rattles, etc. and it looks pretty cool. fucked my camera up, so until i find a new one, no pics. oh, and no more exhaust on the ground problems when the car is laid out.
The Jalopy Journal
