Headers VS 340 manifolds

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1974DartSwinger

1974DartSwinger

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Hey. . . doing my 318 build on the '74 Swinger. I came across a good deal on some 340 exhaust manifolds and was thinking about using those instead of headers. I also found a good deal on some used TTI's so . . .
what do you guys think? I'm not too worried about maximum performance, ease of install and tune ups are more important but I know how bad the stock 318 manifolds flow. How much better are the 340 exhausts or should I just go with headers? I'm going to run the 2.5 inch Jegs duel exhaust.
Thanks!
 
ever tried replacing a starter on a abody with long tube headers. its a *****. id go with the manifolds if you just want something to have. plus some headers require you to pull the motor to install them
 
318 with 340 manifolds......Worked very nice.
Added 2 1/2" dual exhaust with a H-pipe. This set-up would roast the tires !!
For what you are looking for, manifolds all the way.

Picture 498.jpg
 
Thanks for the tips.
I'm also leaning towards the 340 manifolds. Its going to be a fun street machine just have to get the weather to work (im in michigan!) and drop the motor in.

She's a stock bottom end 318 (ran awsome before yoinking the motor)
Edelbrock 600 electric choke and Edelbrock performer duel plane intake. Comp 268 cam and lifters, Comp valve springs. Light porting/gasket matching done by myself and 20 tous shaved off the heads with thin MP head gaskets. and now I guess 340 exhaust manifolds with 2.5 duels into dynomax mufflers
All that mated to the factory 904 with a total rebuild and trans-go stage II shift kit and a TCI 2500 stall. 8 1/4 with 3.23s for now (3.55 posi soon)

I think the 220 60 R14 BF goodrich's dont have a chance ;)
 
If your getting a good price on the tti's..why not??..they are pretty easy to install(no need to remove the motor) you'll need to use the mini starter no big deal,changing plugs are a breeze..performance wise headers over manifolds everytime!!!
 
For what YOU want, 340 manifolds are the obvious answer.

Plus, show me ANY pair of headers that you can use for a few years, remove them, and sell them for more than you paid.
 
how cheap are you getting the manifolds? i would buy the manifolds and sell them for a nice profit and run the tti headders. plugs are easy to get to and the starter is easy to get out with tti's
 
fourspeed said:
For what YOU want, 340 manifolds are the obvious answer.

Plus, show me ANY pair of headers that you can use for a few years, remove them, and sell them for more than you paid.
Click to expand...

For MY money its headers over manifold always!!!!
 
My $99.00 P.A.W. headers worked out great. They were not too difficult to install but definitely more trouble than manifolds. I would suspect they make a fair amount of power compared to manifolds. Changing plugs is not difficult, no mini-starter was required and no right angle oil filter adapter either.

Been on the car ten years and still have plenty of metal left on them.

Manifolds should last forever and if you lean towards the purist side there is absolutely nothing wrong with running manifolds. I am running manifolds on both my 70's Camaros because they would make the floorboards get too hot. Camaro manifolds flow pretty good too. That driver side A body manifold looks like a cork though.

If I was going to run manifolds I would install b-body ones again, they are cheap and they flow. Getting pipes to fit on the driver side is a challenge though.
 
1974DartSwinger said:
Hey. . . doing my 318 build on the '74 Swinger. I came across a good deal on some 340 exhaust manifolds and was thinking about using those instead of headers. I also found a good deal on some used TTI's so . . .
what do you guys think? I'm not too worried about maximum performance, ease of install and tune ups are more important but I know how bad the stock 318 manifolds flow. How much better are the 340 exhausts or should I just go with headers? I'm going to run the 2.5 inch Jegs duel exhaust.
Thanks!
Click to expand...
http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/index.html
good read~
 
Ive read in a writing by mullin and co. good headers flow about 5% better than the 340 manifolds hmmmmm and easy to change the starter........
 
i have some crappy hooker headers but i got a good deal on them and my high flow 360 manifolds woundnt clear my power steering box

there werent to bad to install put it only took about 30 to 45 mins a side to do
and i got them for 50 bucks brand new in the box
 
Hmmm . . . this is a hard call. . .. since the engine is already out I'm now kinda leaning towards the used TTI's $250 for a nice used set of nickle plated, can't go wrong. May pick up the HP 340s too and try to make a little cash out of those as well.
 
1974DartSwinger said:
Hmmm . . . this is a hard call. . .. since the engine is already out I'm now kinda leaning towards the used TTI's $250 for a nice used set of nickle plated, can't go wrong. May pick up the HP 340s too and try to make a little cash out of those as well.
Click to expand...



For that price I would pick up the TTI's if they are not all dented and jacked up.
 
74, let me tell you some facts and you can decide. When I bought my 69 340 four speed Swinger in 77, it had headers on it. Dad had an automatic 69. His would whoop mine at the track. Both ran about 14.30s or so with good tires. Both were dead STOCK. Mine had headers on it. I cut one side off and went back to the strip with one manifold and one header. It was about a tenth quicker than it had been. So, I cut the other side off and put on the other stock manifold and it picked up almost another tenth; the headers have never been back on my car.

For a 318 that you want to run and sound great, put the stock 340 manifolds on with 2.5" front pipes if you want a bit more flow and never look back. Regardless of what headers cost, these will work almost the same (if not better), last forever, and never give you trouble and never need resealed.

I hate headers on STOCK engines. The gain they provide is not worth the hassle they create on STOCK engines. Modified, different story.
Tom
 
Ahhhh too many choices . . .well two, but still! thats one too many lol . .

I checked out the mopar muscle website link . . . thats a solid 25 more ponies for the TTIs . . . but the 340s go with my whole "sleeper" philosophy I've alaways lived by . . . hmmmmm 340 manifolds painted grabber green with a chrystler blue engine sounds fun
I'm shooting for about 300 hp at the wheels. I think thats not going to be a problem with around 9.0:1, the 268 cam, edy carb/intake and my own port work. The exhaust is just my missing link right now.
I'd be happy running low 14s with street tires and mid/low 13s with some suspention mods: SS springs, good shocks, sub-frame connects and cheater slicks.
Big horse power doesnt hurt but traction is the name of the game; thus the 2500 stall converter in my trans-go tricked 904.
 
Before you spend alot on 340 manifolds here is some interesting information. http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/index.html Check out this test by mopar muscle on a 300 HP crate 360. Less then 10 hp gain going from 318 to 340 manifolds, and less then 20 going from 318 manifolds to TTI's. If your car is a mild build and a cruser I would just use the 360 pieces that match the ports and save some money. If your planning on a hot engine then of course these numbers would probably spread out more I think.
 
How did you guys get the 340 manifolds to seal against the smaller 318 ports?
 
Thats a nice looking notchback, Bob. I'v always been a sucker for a set of Cragars. Sharp.
 
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