Allen's Chambered Exhaust on a 1980 4 speed car?
 

I am planning to replace the exhaust on my 80 L-48 4 speed. The car is all stock and I don't want to put headers on it. The original exhaust is on its last leg. Huge holes,rusted through, turn down tip missing on one side. The car actually sounds really good with all the exhaust holes (Very deep tone burble) but its about to fall off. I am considering going with the Allen's chambered exhaust. I called them up and they were very courteous and helpful. I am trying to decide whether to keep my stock cross member and install the '80 to 82 Off Road' Allen's Chambered Exhaust. Or retrofit the car with a 79 and older true dual style cross member.Using the older style cross member would allow me to install the "68 to 79 Standard' Allen's Chambered Exhaust. Both systems have 4 mufflers but the 80 to 82 Off Road system has shorter mufflers up under the car due to space limitations of routing both pipes on one side. I plan to add an X-pipe to smooth the exhaust tone. Has anyone heard both systems? Is it worth the trouble and expense to change out the cross member? I have seen videos of the 68 to 79 Allen's Chambered Exhaust on Youtube. It sounds really good. Have not heard the 80 to 82 set up. I don't mind loud I just want a really deep exhaust note. The factory 2 into 1 back to 2 has a very smooth sound. I have considered going with a factory Y up front but with a single 3 inch chambered muffler splitting into a factory style Y pipe and then to the rear chambered mufflers. To my ear the 2 to 1 to 2 exhaust sounds deeper. Using an X pipe will hopefully accomplish the same deep tone

There's a fellow that sells flanges to allow one to make their 4 speed cross member removeable. I bought a set and am planning on doing the conversion myself/with my husband. I don't imagine it should be a real big expense to pay someone else to do it if you brought them as much of the 79 crossmember as you can get. Perhaps you can get a 79 cross-member from an automatic car and save some trouble over getting it out of a 79 manual transmission car.

I'm assuming you will be eliminating the CAT,,,, useing factory size y-pipe likely won't effect the sound,,, ( and give you the X-pipe effect you desire ) ,, try fitting a chambered muffler in the space the CAT was located,, useing a duel outlet muffler at 3" , then run the pipes to your desired exit location,, a good pipe bender can make it all,,, you likely will use steel pipes with a low cost impact on your wallet,

If your wanting a exact sound you have experienced from a specific brand, you will need to buy that exact item,,,,,, So many factors to consider :willy:

a crossover of any type wont make it sound deeper (muffler type may)

An 80 crossmember is already removable, even for the 80 and 81 4-speed. Why not put in an aftermarket crossmember?

The 1980 4-speed came factory with a removable cross-member. Wouldn't have to cut or weld to install aftermarket older style true dual cross member. Just extra $ 200 plus aggrevation of swapping it out

If it was me, the $200 would be an issue, but not the swapping it out.

Yes I would prefer an exact sound from a prefabbed exhaust. While it might be fun to experiment with different set ups I would prefer a one and done. I had a friend in high school who had the best sounding car I've ever heard ( Stock 82 Z28 with 4 speed) All he did was weld a pipe in place of the catalytic converter, cut the rear muffler(s) off and install straight pipes with twin dual Ansa resonators. I have tried many times to replicate that sound to no avail. perhaps it was the smaller 305 v8 or the 2 into one large diameter front y pipe.Installing the straight pipes with Ansa tips never came close to that ultra deep smooth rumble of that Z28. The KBD mufflers I had on a 1979 L-82 4 speed ( older bowtie 2&1/2 outlet cast exhaust manafolds and 2&1/2 true duel straight pipes w/ KBDs )sounded close but no cigar. I have always been so obsessed with 2 and 1/2 inch dual exhausts that I've never had the guts to "PAY" for a factory 2 into 1 front Y pipe. So I suppose that's the last frontier in my quest. My L48 is stock with cast iron 2 inch exhaust manafolds. One lessen I finally learned was that tubular "headers" ruin the sound hands down . Sanderson cast iron headers sound incredible (If you have 800 bucks to drop)

I totally agree. The x pipe, H pipe, or Y pipe does HOWEVER put a stop to that flapping BRAP sound that no doubt we've all heard on cheesy 12 inch Glass-packed dual exhausts. Muffler type... Yep You nailed it there too. At least I know what I don't like at this point. Flowmaster type welded mufflers give out a RASPY Harsh tone I don't care for. Turbo mufflers sound like a family sedan exhaust to me and the dreaded flappety brap of glass packs is my worst nightmare. Some of the better made longer glass packs from Summit Racing sound pretty decent with a cross-over.

I tried to find these Sanderson cast iron headers but the only thing I see on their web site that is cast iron looks pretty much like a factory exhaust manifold with some sort of weird embossing on the casting. $595 U.S.

Whoops failed to read your post before I said same. Why? Just the aggrevation of wrestling rusty seized bolts or paying someone else to do it. But if I had to do it to obtain the sound I'm after It would be worth the 200 extra bucks for the cross member if I had the patience to self install.. I have heard that unless the OEM duel exhaust hanger is used (attaches in front of the Cross member) you get annoying rattle. So that's more cash too.

I'd love to hear a small block with stock iron manafolds with this set up

I spent a lot of time under my 80 4-speed, thinking about the exhaust problem. My "best" idea was to get a 2-in, 2-out Magnaflow muffler (tiny), that would fit under the passenger seat. I could keep the stock routing, mostly, but I'd still have to notch the stock crossmember to allow for the dual exhaust routed down one side. It would give the benefit of the crossover, and still allow for additional mufflers in the stock position. Once I realized that fabricating that would be a chore (I don't have a welder), I figured that an aftermarket crossmember would make a true-dual install a lot easier.

In the end, I wound up buying sidepipe headers off of Craigslist instead, but @Bee Jay had done something similar with the same muffler using the spare tire cavity on his car. https://www.corvetteforum.com/forums...w-exhaust.html

I hope that helps.

Ok, given the list that you just put together I think I may have an idea of the type of sound that you are looking for. Have you considered Borla exhaust? The first video is their 'tame' setup, the second has a meaner sounding setup.