On my '29 AV8 I'm currently just running Lakes Headers for an exhaust system. I'd like to fab an exhaust to run underneath and out the back from the current header cone. I would like some information on what was a "typical" diameter pipe used without any mufflers. Also how good or bad did it sound. I'm tired of the fumes drifting into the ****pit even with turn outs. And would like a more mellow sound from the rear of the car. The engine is a '46 .020 overbore, stock stroke, H&H reground cam, ported and polished. Offenhauser super dual manifold with 94's. I'm thinking 1 7/8 but not larger than 2 inches but I'd like some experienced opinions. Are mufflers a must or will this be good too?
I've been told that a Flathead sounds best through 13/4". I ran mine with a MCF full race cam with 2" pipes and sounded great but got annoying after a while. Am now running gl*** packs and is nice & mellow. However I'm sure my Merc is longer than your A.
yeah like slopok i ran inch and three quarters also. got tired of it and went to porters nice and mellow now. 51 merc with the flatty.
No mufflers gets old soon and to much attention. 1 3/4" with gl***pack type mufflers is my choice. Gary
I think I knew in the back of my mind that Smittys or Porters were the way to go. Can always build it with a straight pipe and replace it with muffler if it's too noisy. Thanks for your reply. How about any Model A guys?
1-3/4" was the flathead standard thru the '40s, '50s, and into the '60s. (most muffler shops also recommended that diameter for Cads, Oldses.) That diameter pipe was the 'norm' for dual straights, but my friend George Hershman had 2" installed with 2.5" X 4 ft. scavenger pipes on his '46 Tudor. The flathead sounded JUST like an Olds! That George.....
If you run it with out mufflers all you are going to do is Piss Off the cops and every one in your neighborhood. Act like a grown up and put a good set of mufflers and tail pipes on it and enjoy the ride.
I ran 2 inch pipes [no mufflers] below the axle with a stock flathead. Was quiet unless I really jumped on it. I was surprised and expected a lot more noise from it, And I was running tubular headers.
Taper the tubing size down ahead of the rear axle out to the rear exit to 1.5". The noise level is reduced quite a bit with the smaller tubing at idle and cruise but will still bark when you open the throttles.
I wouldn't run without mufflers, you need back pressure for scavenging and that exhaust pulse. There are three (3) types of muffler; absorption, restriction and reflection. Absorption are the simplest i.e Cherry Bomb, Smittys, Porters. Too large a diameter is detrimental just as too small a diameter is restrictive. Quality gl***packs and a full 2" system sounds good to me.
I believe Rocky ran 2" pipes on his old pickup,you might send him a PM and he can tell you how they worked. HRP
I vote 3" with a cross over. Hello, single exhaust might be cool. You all ways go back and add the mufflers. Posted using the Full Custom H.A.M.B. App!
1-3/4 straight piped out to the back,sounds awesome,but does get a little loud after a while! Bob drake tubular headers.
I have to say that I will agree with the guys saying don't be a juvenile and get some mufflers. The exhaust system I am presently building will have 2.5 " tubing and Porter steel pack mufflers. It will sound better than any straight pipe exhaust with no mufflers.
I have had 1 3/4 straight for years on my 48 ford. With the stock engine and a 400jr it was a lot more radical but quieter than it is now. I now have a 296 with the 400 Jr. I have many of miles this summer on it and still glad I have straight pipes. I have fenton headers also
im telling my age here, but back in the late fiftys we took and ran a cutout right in front of the mufflers than ran a pipe off that to just in back of rear wheels. straight pipes when you wanted to raise hell and mufflers out the back when the cops where around.
The Jalopy Journal
