I know there are some automotive experts on here, if you don't mind a question. I'm dropping a Buick 231 V-6 engine into an old military jeep. The exhaust tube from the header on the right bank of cylinders (facing forward) has to go down and then cross over in front of the tranny where it will then meet up with the tube from the header on the left, where it will eventually run into a muffler and then out the back. In a perfect world, I'd have a rearward facing sweep in that cross-tube coming from the left header (facing forward) where it mates with the exhaust tube from the left bank, but I don't have room for a 90 degree bend with a sweep. Is there a problem if I just come straight with the cross tube from the left at a 90 degree angle with no rearward sweep? The left and right down tubes from the headers are 2.0". The tubing is 2.5" where the left cross-tube comes in and then its all 2.5" tubing down-stream from there.
TIA

Don't do it. There needs to be a sweep. Or run dual exhausts all the way back.

The guy that's doing my exhaust (a muffler shop) says he's seen factory exhaust where the one side comes in at a 90 to tube from the other side, but common sense says to have a sweep. Question is whether common sense is right. 'Preciate your advise.

run duals, you can put a 90 cross over on duals.

At any speed below wide open throttle, it wouldn't matter if you put a corkscrew in the exhaust pipe. One bank of a 231 engine only has 115 cubic inches, and each cylinder only has 39 cubes. With pipes the size you're describing, that engine could run 5000 RPM with very little back pressure. At least that's what I've found in 30+ years of doing dyno testing on round track racing engines.
Jerry

Problem is, I don't have room for duals. On these V-6 jeep conversions, you have to shift the engine and tranny right about 1.75" and it just doesn't leave from for exhaust down the right side of the frame rail (facing forward) without dropping it below the frame rail and I don't want that either. My guy could have welded in a sweep where they crossed over, he just didn't want to and now I have to cut if out and start over. What a mess. Wish I had the skill to do this myself. Hate having to rely on people who can't do it right and cut corners.

Sweep doesn't really matter, the engine doesn't know what direction it's going. What matters is turbulence and equidistant lengths. Ideally, you'd want a straight line with the exhaust the same length as the intake. Varying the length of the exhaust and collectors does very interesting things to the torque and hp curves, but, as this is going into a jeep, I don't reckon you're too concerned with peak performance.

With what you are describing there would be some loss due to inefficiency and interference, but not enough to worry about.

Thank you everyone. I appreciate your responses. This board is such a great resource.

Pretty much this, it’s not a performance build so don’t make it hard on yourself.

Put a snorkel on it.
Or corvette/viper style side pipes...

Run 'em down the outside of the body, weld a little pad on 'em - and call 'em nerf bars and steps !

Tarquin,

Go to EarlyCJ5 . There are a lot of guys who have done this conversion, lots of reference and a great bunch of guys.

Tarquin;

I had a '69 CJ5 that had the factory V6 engine.

I put hooker headers on it, and ran each pipe off the headers, out in front of the rear wheels.

I had to use short glass pack mufflers, off the headers, then make a 90 degree bend, right by the rear tires.

Worked great, but was a little loud. I was young then and loved the sound of that screaming V6!

Virgil B.

not Having a sweep won’t make any difference. It isn’t a high performance application