Skip to main content

I need some advice from the veteran big-block exhaust wizards.
I've got bus heads on my engine, and I have enough clearance under my transmission for a collector. It's a 2366 (71 stroke with 103s in it), so I'm going with a three-inch pipe and a Flowmaster muffler. I want to hog the muffler out one side or the other, rather than the rear because of the way the thing flips up and cuts into the space available back there.
What I'd like to do is vent the exhaust straight down from each port -- because I have to -- and then turn the pipes right away by varying degrees and aim them to a point directly under the axles.
If I stick the collector under the tranny and aim the three-inch jobber forward, I could go out under the door on either side.
I want to go out to the right side.
I've got plenty of material to attach to and enough height at the sides of the car to allow for that pipe to come out. The section of pipe with the muffler on it is done already, wrapped with fiberglass and overall about 20 inches long. I'll take a photo of it tomorrow.
I need to know a couple things from the Conventional Wisdom Department. One, I've never had a fiberglass-bodied car before this one. I don't know if dumping that exhaust within a half-inch of the rear fender (ahead of the tire) will distort the glasswork, and two, I don't know what the wisdom of putting the collector under the transmission is.
I can't tuck much in the way of tubing into the void-space behind the block anymore, as I said. The rounded lip of the bottom of the bodywork comes up and in, almost directly below the plane of the pulley by a couple inches. I'll try to take a more descriptive picture of that, too.
Opinions would be very helpful. ...

Original Post

Replies sorted oldest to newest

I need some advice from the veteran big-block exhaust wizards.
I've got bus heads on my engine, and I have enough clearance under my transmission for a collector. It's a 2366 (71 stroke with 103s in it), so I'm going with a three-inch pipe and a Flowmaster muffler. I want to hog the muffler out one side or the other, rather than the rear because of the way the thing flips up and cuts into the space available back there.
What I'd like to do is vent the exhaust straight down from each port -- because I have to -- and then turn the pipes right away by varying degrees and aim them to a point directly under the axles.
If I stick the collector under the tranny and aim the three-inch jobber forward, I could go out under the door on either side.
I want to go out to the right side.
I've got plenty of material to attach to and enough height at the sides of the car to allow for that pipe to come out. The section of pipe with the muffler on it is done already, wrapped with fiberglass and overall about 20 inches long. I'll take a photo of it tomorrow.
I need to know a couple things from the Conventional Wisdom Department. One, I've never had a fiberglass-bodied car before this one. I don't know if dumping that exhaust within a half-inch of the rear fender (ahead of the tire) will distort the glasswork, and two, I don't know what the wisdom of putting the collector under the transmission is.
I can't tuck much in the way of tubing into the void-space behind the block anymore, as I said. The rounded lip of the bottom of the bodywork comes up and in, almost directly below the plane of the pulley by a couple inches. I'll try to take a more descriptive picture of that, too.
Opinions would be very helpful. ...

Attachments

Images (3)
  • parts bin two 042006
  • close up of rear hinge mechanism 043006
  • DTM with tins in place 042606
Bruce, the hatched back end won't actually hit anything if I do that carefully, but the bottom of the fender comes back to within a few inches of the tire in the up position (photos, below).
The pipe would also be hit by everything the tire flings up, unless I put some kind of deflector plate on it.
The same curve that looks so good when the body's parallel to the ground curves inward, and I'm fairly sure I'd have to cut the pipe short for it to clear and still be close to the edge of the body. My guess is that the bottom lip of the bodywork would catch the pipe as I raise the back, so the pipe would have to actually vent inside and under the shell. I'm sure that would be problematic.
I either have to cut a 959-style grille into the fender (which I may yet do) or stick it out below the leading edge of the hatch behind the door for it to exhaust in the clear.
All that's assuming I can make the header pipes meet under the transmission somewhere where I'll have enough room for a ninety in a three-inch pipe.
AUUUGH!

Chuck, that's funny! Should I look through my bucket for a new oval-port head to send you?

Attachments

Images (3)
  • progress 043006
  • hoops and scoops long shot 043006
  • rear hatch up dr side front 043006
Dave, there's always room for improvement. I've never even heard this thing run, so I'm already a little scared.
I had two turbos from a Maserati available to me from the start -- and they're still there -- but they're reported to be crummy over time and prone to mechanical failure and I don't know enough about what happens when they break down to risk it on an untried car.
The other simple reason I decided not to turbo just yet is that I have no idea how this crate is going to perform with 210 horses and 1100 pounds of curb weight. If I went the wild cam and turbo route in a car this light, I'd probably realize 315hp (according to the mechanic, based on the Type IV powerplants he makes for the dragsters he builds).
He did some math for me the other day; my 2366 is apparently based on some formula like 103x103x71x.001x3.1416; the bore, the bore, the stroke, a thousandth of that number times Pi. If I had a 78 crank and 105s, 109s or whatever other huge pistons there are out there, I could conceivably come out with a 2700cc engine.
Again, what I would do with that probably involves me winding up in a long, wooden box.
I need to get used to what I have before I play with magic I REALLY don't understand.

Unrelated: Go to Fire Station 30 in Honolulu and say hello to Captain John Drake before he retires in a year or so. He'll buy you a cup of coffee if you drive your car over and tell him I said aloha!
That's my uncle. He's the engine company captain on the first watch.
Post Content
×
×
×
×
Link copied to your clipboard.
×
×