220 Cummins, Backdrop Exhaust Manifold

[1961H67]

I want to put a backdrop manifold on my 220 in my 1951 LJ restoration project, I have 2  different styles, one comes down at the back on a 45 degree and has a fin ( or baffle ) inside, the other comes down at a 90 degree, not sure if it has any type of baffling in it or not, they both came off Emeryvilles , Any ideas of the best choice for that good sound? 

[carlotpilot]

that bottom picture would be my choice`  btw i`m looking for one like that

[carlotpilot]

however the top one may be the only choice in an lj

[1961H67]

Thanks, I need to look at the top one to see if there is a baffle in it when I get a chance, I think I can make ether one work, the top will be easier like you said, I just want the best sounding one , thanks 

[mattb73lt]

I'm doing the same to a 220, but in a L cab B-73. I have the same clearance concerns as the truck is far from assembled. I also have the lower one, with the baffle. The upper one is interesting, and may be easier to install.

Edited March 11, 2021 by mattb73lt

[1961H67]

Thanks , I’m thinking the same thing you are about the top one, I have never seen one like it , but if I figure out which one is going to sound the best hopefully I can make it work, I have the cab off now, I may bolt one on and set the cab in place temporarily with the forklift just to check clearance,,, thanks .

[james j neiweem]

I don't know if you can get the split manifold but that will  give you the put put sound

[1961H67]

I bolted this one on , it’s going to be tight, I may try the other, I haven’t found anyone that can tell me what the one laying on the the tailgate sounds like,, I may try to start it with each one ,,, probably a lot of trouble for just a different sound,,, But I think it will be worth it 

[mattb73lt]

Could you post a picture from the transmission looking forward to the manifold? Or maybe downward showing the manifold, bell housing and transmission mount? Looking to see where the exhaust pipe might pass through and down.

[1961H67]

Maybe this will help, I’ll set the cab up with a forklift in a couple of weeks hopefully and take a few more pictures, I have a feeling it’s going to take a terrible tight elbow to miss the firewall, and still might not work with out raising the floor some .

[mattb73lt]

Thank you!! Those are very helpful. I’m thinking about passing my pipe downward, just aft of the bell housings but before the transmission mount. I may need to run it over the transmission mount where it would be closer to the floorboards. That might be a heat issue, though.

[1961H67]

I’ll keep you posted, I’m going to get the other one , so when I temporarily set the cab on ( I have a lot of rust repair on it to do ) I can play with each style, it’s probably going to be this one if it sounds the best, also I may have to change the original air filter ( oil bath ) because it’s tight back there also, I was thinking of a dry type anyway. 

[mattb73lt]

This is a crappy 35mm pic I took of my truck when I found it. The floorboard has a factory notch on the support that runs across it. I think it’s there to allow an exhaust pipe to run through there above the transmission mount. You can see it if you zoom in on the pic. I’m not sure if there’s enough room to run the pipe downward, after the bell housing. If I run it over the mount, I could wrap it with header wrap to help with the heat.

Edited March 15, 2021 by mattb73lt

[mattb73lt]

6 minutes ago, 1961H67 said:

I’ll keep you posted, I’m going to get the other one , so when I temporarily set the cab on ( I have a lot of rust repair on it to do ) I can play with each style, it’s probably going to be this one if it sounds the best, also I may have to change the original air filter ( oil bath ) because it’s tight back there also, I was thinking of a dry type anyway. 

I was wondering on that other manifold, on the tailgate, if you might run the pipe over the frame rail to the outside, then run it back? 

[1961H67]

Yes I see it, I believe you will have more room to play with then me , you may be correct on running the other one over the frame, or I may have to “ Make a Factory Notch “ in the floor , also your air cleaner is out of the way. We’re all caught up in the Backdrop Sound,,, I’ll I’m thinking we’re both going to make them work! 

[mattb73lt]

In talking to the old timers it was. I want to get the sound right, too. I’m back and forth on a straight pipe or a muffler, too. Maybe just a resonator. I also don’t want to go deaf on long trips. Another thought was an under frame muffler. I’m installing a stack support to the frame, to remove the stack off the corner of the cab. I didn’t want it resonating the cab, creating other noise. The whole cab has Lizard Skin sound and heat coating applied to it. I’ll supplement that with patches of Dynamat. I want the sound, but I also want it to be comfortable.

[1961H67]

Yep I’m with you on being comfortable, we will probably have to change as we go on this project, When I drove this truck as a teenager it had a muffler beside the transmission ( factory hangers are still there) then just a 4 inch pipe on the cab , after 42 years you would think I would have it figured out! 

[JerryB]

I put a few miles on 220s back in the day with backdrop.  The manifold on the tailgate has a louder pop but the bottom manifold sounds better to me.

Either one without a muffler is extremely loud but it sounds beautiful and unique.  It is much much more loud than a turboed engine.

[1961H67]

Thanks Jerry, I know the bottom one is off a Emeryville , I took it off before they were crushed, a friend of mine said he took the one on the tailgate off his Dads Emeryville back in the 70s and hung it on his shop wall, wondering why they used 2 different styles? Thanks for sharing 

[Truck Shop]

                         With the rear drop manifolds on 220's the standard rear structure/bell housing used was the one Matt73 has in his photo of his 220 above that's painted yellow. With rear drop manifolds Cummins used that bell to lower the starter on the right side. At least that's what I have always seen in a factory built truck with a 220.

 

[1961H67]

Thanks, I see the difference in the 2 bell housings, if I need I could probably index the starter nose and hang it upside down for more clearance, I’m still wondering why Cummins ( or Emeryville) used the 2 styles, there are no restrictions on a cab over ?

[carlotpilot]

that one that turns down & out would have been on a non sleeper cab. 

[1961H67]

Makes good sense, Thanks for the answer, I’ll probably just go with the one that’s easier to install, cause it’s going to be awhile before I can drive it with a full exhaust on it 

 

[1961H67]

My latest backdrop, I can make this work on the LJ cab, it has a 90 deg flange that will rotate , this one has NO baffles, you can see straight to number 6 cylinder ,, I’m hoping for that special sound! 

[mattb73lt]

That might be an easier way to run the pipe back and clear a lot of obstructions. Several military trucks run the exhaust out like that, but then up through the fender in front of the cab. 
You could pass down over the frame rail, then 90 degrees straight back then up to your stack?