I've seen many recommendations in mutliple forums extolling the virtues of a dual exhaust as an "inexpensive" performance modification for the 300 small block. So ok, I'll bite: if I am gonna hang a set of duals under my 66 'Lark with a 300 4bbl, does it have to be a custom fabrication? Is there a factory part, or set of factory parts, that I can use? Or something after-market? Will I have to cut some of my existing pipes, or is there a bolt-on solution? I only ask because my current exhaust system is in excellent condition, and I'm loath to trash it. However, in order to get a little performance bump I'd be willing to unbolt it and install something else. Any suggestions?
I've been researching this for a couple of years, and will probably get the duals this winter. From what other 300/340 owners have told me, there are no pre-made pipes available. Everyone of those owners took their car to a local shop such as Midas or Meinecke, and had the exhaust system custom bent. The stock manifolds were used, and 2" pipes were bent. The shops offered them a variety of mufflers to choose from. No X or H pipes were used. The ones I heard all sounded nice. If you have fitted a 4bbl carb to your '66, then this is a companion upgrade that should help give you more power.
Just my two cents worth... Duals are a great upgrade, however if you just take it to the local muffler hack or chain... well, you get what you pay for... if you're lucky. I'd recommend searching out the local performance exhaust shop. You'll get a far superior product, usually with mandrel bent pipes (no reduction in diameter at the bends) and probably a 2.5 inch system yielding far less backpressure. You'll spend more, but not that much more. They can also do the crossover pipes correctly... a small detail with the important benefit of improved exhaust system scavanging and balance ... better performance and sound, too. So, do up right! Cheers, JMC
I just had duals put on my 300 2bbl found in my 1964 LeSabre. I didn't do it for a performace upgrade, but because the previous owner decided he wanted a dual exhaust system that exited under the rear doors- lame. The thing had resonators on it and some flimsy mufflers, and sounded horrible. I took it to a local muffler shop, but I went to one my family has an ongoing relationship with and is locally owned with no affiliation. I am a big believer in stock, but the previous owner left the manifolds alone, and about two inches down on each side that used to be the "Y" pipe, he cut it and welded his pipe. The most horrible job you have ever seen. No hangers, just wire looped around. I was glad to get it off! Here are the specifics I had done to mine: I decided to go with the dual exhaust layout that would have come factory with the Wildcat. That involved two pipes down each side into a large transversely mounted muffler with outgoing on opposite sides as incoming. The muffler shop had no problems doing this. The only thing that took some effort was using the flange off the previous pipe connected to the manifold on the new pipe as they had to machine the pipe to work correctly with the flange. Do I see a performace increase? Not really, but I have a 2bbl with an ST300, so it would be negligable. Plus, because I had duals when I got the car, I wouldn't see the difference. What do I like best about my dual exhaust? the look. Isn't it great to know from the head to the rear bumper is all dual? No cat-back, no single pipe and a dual tip, but a real, complete, "system."
re-dual exhaust hey guys any system that is set up for a 67 chevelle wll work so places lke summit have a system for you. Actuall flowmster makes a kit that fits the a-body well (chevelle cutlass skylark gto) etremly well. you have to fab up a pipe to go up tothe maifolds because this is setup for headers adam
What you say is true, but the question is who will fabricate the custom pipes from the stock manifolds to the kit's exhaust pipes. Will your local muffler shop welcome you with a full kit bought elsewhere, and all they get to do is the hardest part? If you have had experience in getting shops to do this partial work, let us know the details.
