Ed, I did this on my '69 Delta, in two steps. First, I simply cut the crossover short of the junction on the passenger side, diverted it to it's own exhaust pipe which ran parrallel to the passenger side until spliting off to the driver's side somewhere near the middle of the car, and, welding shut the junction opening just below the passenger manifold. I ran this way for about two years but didn't really like it.
When I rebuilt the engine I acquired a toro type driver's exhaust manifold which dumped at the #7 cylinder closer to the firewall instead of between #3 and #5 cyclinders, this was done to allow the exhaust (down) tube to go straight back without snaking around the steering box. However there was some interference problems, the manifold didn't completely clear the box so I did two things.
1: I cut the manifold collector diagonally from bottom to top and rotated it until there was a little more clearance then welded it back together(actually had a weld shop do it)
2: I raised the engine up 1" by modifying the motor mounts. No, there was no fan (electric), carb (no spacer), or tailshaft (TH400 long shaft) issues and there is no vibrations at all. Everything still fits and there is now ample clearance for the manifold.
Back to the exhaust, I cut the whole junction off the passenger exhaust manifold, cutting a line parrallel to the rest of the bottom of the manifold, then weleded a flat piece of stock over the hole. This got rid of that nasty "pocket" of dead air space which I figured could only cause turbulance right where it could cause the most damage. Again, I had a welding shop do this. My down tubes are 2.5" and then enlarge to 3" about a foot back from the manifolds. I am very happy with this setup, the only thing I would do in retrospect is not dump the turndowns at the axle, it is a little noisy at very low rpm. I really think the crossover being right under the oil pan contributes to shorter oil/engine life, it has to radiate a ton of heat to the oil pan.
Our B body cars are difficult to fit headers, I don't know of any out of the box. Custom headers are the only alternative and they cost big bucks. I have maybe $90 to $120 in the parts and labor on the manifold modifications (including modified motor mounts) and then another $289 in the exhaust parts and labor. So my whole setup cost less than $500. I don't think that can be beat.
[ July 16, 2004: Message edited by: Oldsguy ]</p>
__________________
Dan
'46 2 door
|