41 Plymouth SB Mopar Engine Swap

Ever consider a single exhaust ? With a big diameter of course. Run it down beside the fuel tank like stock, somewhat easier to route.

 

The Aussie XD Falcon is one that you can't run dual set up in & some have gone with a 3" system, supposedly will make more power than a 2" dual.

 

I didn't consider that since I'm trying for a more traditional look. Thanks anyway. I'm getting ready to post some pics.

 

Well, the cheap exhaust flanges I bought ended up being just that. Cheap. There's no way I'm going to put the time and effort I'm getting ready to expend and put that junk on my car.

SO, I made my own. Some 1/2" thick flat bar, a hole saw on a really slow drill press at work, some band saw work and some belt sander work and I now have some nice flanges.

Also, I worked on the holes in my frame and planned my exhaust layout from the engine to the rear axle. The rear axle and back will have to wait until I put the body and fuel tank back on the chassis.

As you can see, I enlarged the holes in the front portion of the chassis and connected two holes together at the rear portion of the X member. Should I reinforce around this large hole? I was thinking about welding some 1/8" X 1" flat bar above and below it but I hate the way that looks.

I'm open to suggestions but my path is pretty much laid out for me. If I get all my materials together, maybe I can do this next weekend.

 

Here are the frame shots.

 

Question of the night. Does anyone know of a center dump shorty style header for SB Mopars? Can a Chevy Shorty header be adapted? This would greatly simplify my task if I had something like that.

Upon further review, it won't help.

 

Rockable, what if you weld some round stock around your elongated hole, that should reinforce it pretty good. I was actually thinking of doing the same thing with my forty. I've seen shorty headers on e-bay for mopars or you could use stock dodge truck exhaust manifolds.

 

Thanks! I found out that Hedman makes a center dump shorty header. This would have helped me on the DS, but my r&p mount was in the way on the PS.

I've mostly got it worked out without the headers. I may do the round stock trick, that was suggested to me by a friend. sounds simple enough to do, as well. I'll be done with exhaust part by next weekend, hopefully.

 

Ok. Today, I learned to use my Tig Welder............a little. I probably picked the hardest project you could pick to learn on. Welding exhaust pipe is not easy because of all the twists and bends but, overall, I'm pretty happy with the way it turned out.

I bought a couple of the 2 1/4" exhaust kits from Speedway Motors. It includes four each of 45, 90 and 180 degree mandrel bends plus 4 straight sections. Since my system has more than the average bends, I bought two kits. I'll have some leftovers but it's still cheaper than buying the individual bends.

First, on the driver's side, I had to fit the exhaust into a rather small path. In order to visualize it, I got my large shop vac hose and twisted/bent it into position. This really helped me see what I needed to build. I ended up with two close cut 90's to get the pipe around the starter and a 45 to kick it back up toward the hole in my frame rail. This was the one I dreaded most and it wasn't that tough.

On the PS, it was pretty straight forward. I had a 90 to drop the pipe down around the bellhousing and then a 45 to kick it back up to the hole. Both pieces also required some straight extensions.

I tacked it all up and checked and rechecked it before I welded it. MAKE SURE you clean the pipe inside and out with lacquer thinner or some aggessive solvent. There is some sort of crap on the inside that varsol won't cut. It WILL contaminate your welds if you don't clean it out.

After tacking it all up, I Tig'd it all up, ground it down and blasted it. What I love about the Tig is there is a lot less to grind! Also, you can control your heat like nothing else.

The system will use Walker Mega Clamps to separate it between the exhaust manifold and the frame rails, so I can remove them if necessary without pulling the engine. I will also cut the pipes and use the same clamps at the loops that go over the rear axle.

I won't be able to finish the rear part of the exhaust until I get the body back on. It's very likely I will end up with turn outs behind each wheel, as the gas tank will interfere with extending them out the rear in a symmetrical fashion. (sigh)

 

More pics of how the exhaust will be routed.

 

Impressive work Rock. Those welds look really good, you know I'm watching you. It must be a great feeling to know that the end is near!

 

Those look great. You plan on painting or coating the pipes? You could get them ceramic coated grey or black. It would keep them looking nice for years to come and would help cut down on the heat a bit.

 

Thanks, Eric and Dan. I got the second pipes done today.

Then end is near???? I don't think so. There is still a lot to do, Eric.

Dan, I'm thinking about doing that. It's $25 a foot to have them coated and another $250 for the exhaust manifolds.

 

Nice, it would be interesting to see how much room there is between the floor and muffler when you get the body back on. later shawn

 

A couple of inches. It's right below the seat riser portion of the floor.

 

Nothing too exciting this weekend. I just reinforced two of the holes that my exhaust routes through. I made a couple of "benders" out of pipe with a couple of pieces of 1/2" flat stock welded to the side. Clamp the pipe in a vise. Then, you put the 3/8" round stock in the jig, using a pair of vise grips to hold the round stock stationary and heat and wrap it around the pipe. A hammer lick here and there smooths out the curve.

After you're finished wrapping them, cut the excess away and weld the ends together and you're ready for the fun part.

Then, there is the tedious task of welding the suckers in. Not beautiful welds, but serviceable. I hate welding overhead. That, coupled with the starting and stopping makes it hard to have one good continuous looking bead. At least it does for me.

 

Lookin good Rock, keep up the good work!

 

Looking good!
Even if you swap in a different gas tank but keep the same filler, the exhaust won't fit down that left side.
You could get creative and have it go out through the spring/frame, but then servicability and clearance stink.
I went with a single exhaust, my lil 318 won't be screamin at 4K and up much if at all. I may have left a few HP on the table, but cost/complexity/hassle were all down.

Besides, you can hide a pretty big pipe under one of these

http://cgi.ebay.com/ebaymotors/VINT...sories&fits=Make:Plymouth&hash=item2eb6580900

 

Man I love this build! Keep up the good work I'll be watching this thread! The work on the R & P gets me motivated to finally get mine started! You make a lot of hard work look easy!

 

Ha! If you only knew how long it took to learn how to do all this stuff and how many times and things I screwed up, you wouldn't say that!

RSR, What if I route the exhaust pipe under the tank and out the back? I won't know how that looks until I get the body back on. Just wonderin'....... There's also the option of putting the gas tank inside the trunk between the bulkhead and the axle hump............

 

Lookin good rockable!

 

Well, I got the front holes in the frame reinforced today, so I hope I'm done with welding on a creeper for a while.

After getting that done, I worked out my exhaust hangers. I took the business end off of some "red snapper" hangers that I got from Summit and made my own brackets that bolt to the DynoMax clamps. I then weld a 3/8" stud to my frame and there you have it.

Unfortunately, they don't make these clamps in RH and LH, so the other side clampes will be "upside down". At least the threads are long enough to put a nut on, so it should work out ok. You can get a little "adjustment" out of the setup by rotating the clamp a little.

I should finish the other side tomorrow. I have to modify the exhaust tubing a little first.

 

Looks like a professional installation Rock, nice work. Maybe time for a career change?

 

I couldn't afford the pay cut, Eric!

 

Finished up the hangers and the fore portion of the exhaust. I'll have to wait until I get the body on to finish the rear portion. I'm pretty please with how this all turned out and, according to my measurements, I shouldn't have any interference problems with the body. I'll keep my fingers crossed .

Next up, a little bit of clean up grinding and then my least favorite activity - painting the burned up spots. I hate painting.

I'd rather fab metal or do mechanical assembly any day.

 

Looks great, keep up the great work dude!

 

Didn't get a lot accomplished this weekend. I put what I hope is the last patch panel in the floor of my trunk. (Heck, I should have just made a new one. ) No pictures. Not very exciting.

Today, I installed a rear sway bar from a 2000 Crown Vic (18mm). I didn't want to bend the bar, so I made my mounts fit the bar. They are a little longer than I would have wanted if I had a choice. Therefore, I put a gusset on them. Overall, it worked out pretty well. Obviously, I will have to determine the length of my drop links after I get the car pretty much complete but it all should work out correctly.

 

Nice work Rock!

 

Looks great. The mounts look really solid, you'll have no issues at all.

 

Hey Rock! Just checking how you're coming along........looking forward to the next installment of progress reports!