340 exhaust manifolds
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dusterdood
The Duster Guy
I've got a driver side one that's from a '64-'66 A bodies with a 273. Does that help?
Mike
Mike
bobscuda67
Well-Known Member
You better measure the height of your exhaust port on early 273 heads. The 340 exhaust manifold port is taller.
I made this mistake on my 67 273 and although they did bolt on, they did not fit. The flat sealing surface of the heads is not big enough on the bottom and it left a 1\4 inch gap. I am now using magnum heads on a 340 and it just barely seals.
I made this mistake on my 67 273 and although they did bolt on, they did not fit. The flat sealing surface of the heads is not big enough on the bottom and it left a 1\4 inch gap. I am now using magnum heads on a 340 and it just barely seals.
73DartSport340
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Plus HONESTLY unless you just like to throw money OUT THE WINDOW...look into a set of 318/360 manifolds. I think most people realize now on a mild build up that the "vaunted" 340 manifolds gain a WHOPPING 1-2 HP over 360 log manifolds on a 300 HP engine...right? And even on more of a build it may jump up to 5-8 HP more mabey of its really cammed up or something...but when you think of it..is a full set of EXPENSIVE(unless you get lucky) 340 HP manifolds for $400 bucks+ worth that extra 2 HP over a set of 360 manifolds that are dirt cheap?
http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/
Exerpt from the Mopar Muscle test on a 300 HP crate 360
Log 318 manifolds
For our baseline test, we fitted the 360 with the lowest of exhaust low, a set of stock small-passage 318 iron exhaust manifolds. Bolted to the manifolds was a set of 21/4-inch head pipe extensions 24 inches long. So equipped, the 360 put out a respectable 311 hp at 4,600 rpm and 403 lb-ft of torque
log 360 manifolds
We moved up a notch from the early 318 iron manifolds to late 360 iron log-style manifolds. The 360 manifolds are nothing to look at, but the internal passages and outlet are significantly larger than those of the 318 pieces. Power was up a little, moving to 314 hp and 407.1 lb-ft of torque.
so far from 318 to 360 they are up a whopping 3HP and 4ft bls torque
and now Drum Roll!!!!!!!!! the VAUNTED(term used VERY lightly) 340 HP manifolds
Our final test of factory iron was a set of rare and expensive early 340 high-performance manifolds. With the 340 exhaust, the 360 inched up to 315 hp and 409.1 lb-ft of torque, which represented very little gain on this engine.
so the results...from a 318 LOG manifold you gain a WHOPPING 4HP if you go with a 340 manifold and a WHOPPING 1 HP and 2 torque over log 360 manifolds.
guess what I was trying to point out is 340 HP manifolds are expensive BUT GIVE VERY LITTLE GAIN over 318/360 manifolds on a typical 300(311 hp by the results)hp engine. so I was just trying to possibly save you $$$ vs VERY LITTLE performance gain.
http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/
Exerpt from the Mopar Muscle test on a 300 HP crate 360
Log 318 manifolds
For our baseline test, we fitted the 360 with the lowest of exhaust low, a set of stock small-passage 318 iron exhaust manifolds. Bolted to the manifolds was a set of 21/4-inch head pipe extensions 24 inches long. So equipped, the 360 put out a respectable 311 hp at 4,600 rpm and 403 lb-ft of torque
log 360 manifolds
We moved up a notch from the early 318 iron manifolds to late 360 iron log-style manifolds. The 360 manifolds are nothing to look at, but the internal passages and outlet are significantly larger than those of the 318 pieces. Power was up a little, moving to 314 hp and 407.1 lb-ft of torque.
so far from 318 to 360 they are up a whopping 3HP and 4ft bls torque
and now Drum Roll!!!!!!!!! the VAUNTED(term used VERY lightly) 340 HP manifolds
Our final test of factory iron was a set of rare and expensive early 340 high-performance manifolds. With the 340 exhaust, the 360 inched up to 315 hp and 409.1 lb-ft of torque, which represented very little gain on this engine.
so the results...from a 318 LOG manifold you gain a WHOPPING 4HP if you go with a 340 manifold and a WHOPPING 1 HP and 2 torque over log 360 manifolds.
guess what I was trying to point out is 340 HP manifolds are expensive BUT GIVE VERY LITTLE GAIN over 318/360 manifolds on a typical 300(311 hp by the results)hp engine. so I was just trying to possibly save you $$$ vs VERY LITTLE performance gain.
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