I have been looking into converting to a dual exhaust on my 307 malibu but everything I have found only shows single exhaust for that size motor, 350 shows dual, is there any difference in manifold that I would have a problem, going to a dual???

exhaust manifolds for all small blocks are the same.. meaning that the 350 pipes will work just fine on your 307..

First of all, in my opinion, dual exhausts will be extremely unlikely to be noticeably more efficient than single exhaust at engine speeds below say 3,500 to 4,000 rpm. Then they also run cooler than a single exhaust so the mufflers and tailpipes rust out sooner and you have two to replace rather than one each. It does look "cooler" to have twice pipes

Most likely all the pieces you need are still available from a "real" parts store. Walker, Maremont, and Arvin are some manufacturers. Check www.walkerexhaust.com (http://www.walkerexhaust.com) catalogue lookup.

Any good muffler shop could fix you right up with a nice custom set in less than a day for a few hundreds of bucks. Good luck.

My $0.02

Well, I'm 180deg from JJ. I can't imagine having a V-8 Chevelle with only one pipe out the back. When we got the 68 Chevelle with a 307 PG for my son's 16th birthday, the VERY first thing I did was take it to my favorite muffler shop and had dual exhaust installed. And 2 1/2in at that! At one time, 2 1/2in pipes back to the muffler were available, for MANY cars with a SB. Where the pipe mated to the ex manifold, it was 2in. Then, just a few inches down, the pipe was 2 1/2in for the remaining length. I don't think this style is available anymore from the parts sources (except aftermarket repo), but ANY GOOD muffler shop can make them. Although, I have to give you this WARNING. Some custom muffler/exhaust shops just do not, or cannot, or will not fabricate an exhaust system EXACTLY the way you want it unless you stand right there and supervise. So, just like anything else, if you find a place which does quality work, stick with them, even if it costs a little extra.