Exhaust Manifold Application Question

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tubbedamx

tubbedamx

Location Boise, Idaho
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Hi, I have a pair of manifolds with these numbers...I did a search on this site and they come up as 318 manifolds. I know they were removed from a '73 340 duster but I only know the history of the car from '90 so they could have been changed out between '73-90 unless they are correct.

2843953 Passenger side "Center dump"
2951123 Drivers side "Rear dump"

Question:
Could these be used for a '67 barracuda with a bone stock mid '70s 360/auto tranny?? I set the drivers side on and it looks like the exhaust pipe might get close to the starter. Measuring the outlet, they look like 1 3/4 or so. I was going to run 2 1/2 as quick as I could.

Heres a couple of pics I sandblasted them then used POR-20 Black Velvet manifold paint. Cooked them in an oven at 500 degrees to set the paint.
DSC07965.jpg

DSC07964.jpg
 
they do look good. I dont know about numbers but the drivers side one looks like a 340 manifold.
 
they are both 318 manifolds. you will be cutting the flow of exhaust down with the smaller 318 maniflods on that engine. you should find some real 340 manifolds which have the bigger runners and have a larger dump on the end. the main difference is the flange on the ends are bigger. they will dump in the same locations. i just changed my 318 manifolds on my wifes car to the 340 hi-po manifolds and it fit fine. the engine on the driverside had to be pushed over some to get it in but it fit fine after that.
 
Jeeze, I did a little looking around and 340 manifolds have a bit of a price tag. Unless I can find somebody who wants to trade "Which I doubt will happen" I'll have to shop around the junk yards and the papers.

Thanks for helping me ID the manifolds.
 
tubbedamx said:
Jeeze, I did a little looking around and 340 manifolds have a bit of a price tag. Unless I can find somebody who wants to trade "Which I doubt will happen" I'll have to shop around the junk yards and the papers.

Thanks for helping me ID the manifolds.
Click to expand...

Yeah , They are a few still out there but they are few and far between...
 
Regular 340 or 360 A body manifolds would be better the later ones 73 and up are somewhat cheaper. But you won't loose much on a mild street motor either way. Check out Mopar Muscle test of exhaust.http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/index.html

With a 300 HP crate motor open exhaust the 318 manifolds made 311 HP the rare 340 HP units made 315. Now this was with open exhaust 24" head pipes. Looks the rest of the exhaust system is a better place to look for gains. Of course with a real hot motor the better parts would show more gains but good TTI street headers only made 327 HP 16 over the lowly 318 parts. I was going to install headers on my 73 Dart with a mild 318 till I saw this and am now re-thinking.
 
Now thats pretty interesting....not a significant loss in power using the 318 manifolds over the 340 manifolds. Either way for now i'm going to run these manifolds...

Is there anything to be gained or is it necesarry using a 90 degree oil filter adapter with manifolds?
When I pulled the 273 out of the barracuda I noticed it had one but it had no exhaust so it may have had headers at one point.
 
You may need the 90 adapter for exhaust clearance I know it is required if you use the HP 340 manifolds. Generally cars that came with duals used them. I had duals put on my 73 Dart with a 318 and those manifolds and there is filter clearance but it is tight. I run the 16 filter instead of the 43 gives about another 1/2 of clearance. If your having the exhaust bent up from scratch i think a good shop will get you buy without an adapter. If your going to run larger pipe for future upgrades and reduce it to fit the manifolds you may need the adapter.
 
tubbedamx said:
Now thats pretty interesting....not a significant loss in power using the 318 manifolds over the 340 manifolds. Either way for now i'm going to run these manifolds...

Is there anything to be gained or is it necesarry using a 90 degree oil filter adapter with manifolds?
When I pulled the 273 out of the barracuda I noticed it had one but it had no exhaust so it may have had headers at one point.
Click to expand...
Hey, the manifolds' will work. If you go to the muffler shop, have themmatch a piece of pipe to the head pipe diameter. have your oil filter in place then have them bend the pipe to clear. I'd only go 1and3/4 inch if that's correct to bend it around the filter, then go with 2&1/4 on back. I've got manifold for the 69-70 318 and it is the same as the 73-74 340 and has a 2 inch exit compared to the 2&1/4 exit on the 70 340 manifolds. I messed up on the exhaust on my 73 as I had a right angle adapter on my 73 340 motor. We pulled that motor out as it was the original (I bought the car new in Oct. '72) and did not want to mess anything up til I can overhaul it (200,000 miles). Break em in the way you want em to run. We set a 318 in for the time being and had to put adapter on as the exhaust was made for the adapter. My '71 was done with out and either oil filter will work. Have headers on it now and the straight on filter works like a dream. Allen
 
Thanks for the info... As soon as I get the 8 3/4 in I'll be getting the exhaust put on.
 
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