Hot Rods 1-3/4 Dual Pipes big enough (AV8)?

I am building a 284" stoker 8BA flathead for my AV8. I have 1-3/4 pipes running all the way out the back with a 12" long glass pack muffler on each side. Is that too restrictive for a hot street flathead?

 

Nope. It'll work just fine in my opinion. I have 1 3/4 on a 471 blown 8BA, Smittys, reds headers, sounds stupid cool. Ran fine at speed on the dyno.

 

If any concern, you can put a balance tube (an H) config. accross and have less back pressure.

 

Good point. Here is an interesting observation I made with my car. I originally started the motor and did the burn-in with a crossover. Real estate was locking under the car so we ditched the cross tube and the exhaust tone was soooo much cooler. Like a Harley, flatheads have a signature exhaust noise (even with the blower) that other motors just can't replicate.

 

With 140 cubes per side you will be good. Your average rice burner of 2.3L only has a 1 3/4 pipe. I dont imagine you have a lot of space under there for bigger anyway.
If you already have 1 3/4 in there run with it .

 

Not only will 1 3/4" pipes be plenty big, they'll also make the flathead sound "right". Keep both sides separate and you'll get that traditional flaheat "burble" tone that's often lost when larger tubing and "H pipes" are used. A vintage hot rod should also sound vintage...in my humble opinion.

 

Ok great!! The exhaust came out well and I wasn’t excited about doing it over.

 

Sound track? Share, my flatheaded brotha.

 

^^^^^^^Ditto what he said......^^^^^^^

 

Pipes are too small.

Just kidding, that sounds awesome!!!!!!

 

Dang! That sounds good. And here I spent a lot of time snaking a 2" system back from the 276" Merc on my '36 3-window. I thought I was a hero.

 

That’s still the tired .030 over 239, that’s why the smoke. I’m pulling the engine next week for the rebuild and cubic inch increase to 284. Supposed to be a Potvin 3/8 cam. Will know for sure once I measure it. May switch to a 1007B for more torque?? Not sure and not easy to switch once back together.

 

True that! Have fun wit the rebuild, post pictures.

 

Sounded like a motor cycle from my end....
Sweeeeeeeeeet!

 

A flathead engine is too restrictive for a flathead. You will be just fine with 1 3/4" tubes.

 

You've got it right, put blocking plates on the heat riser passages in the intake and it will be great. We always used pennies, but copper pennies are hard to find now.