big block exhaust manifolds

[dodge66500]

i have a 73 440 in 66 dodge and would like to know if i would gain any by using some of 68 high performance exhaust manifolds instead of stock ones. any help would be appreciated

[djswwg]

they may help some, just depends on how much more volume they flow than your current ones. 440's work good with big exhaust, like at least 21/2" with an h-pipe. If in doubt, get a good set of headers. djs

[COLORMECLONE]

dodge,i think you will gain some if you have low-perf log type exh. manifolds on it now.

[PRO]

You'll pick up 15-20 ponies,you'll notice it in the midrange mostly.....PRO...

[440 Jim]

I think they will work great with any 440, but what is the rest of the engine build up? I am running a 235/245 deg @0.050 cam, 10.7 CR with forged quenched dome Arias pistons, 850 Speed Demon, M1 single plane in my street car with power brakes and 3.91 gears...


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440 Jim
E-Body Fish: 12.8 sec 1/4 mile with stock exhaust manifolds, 3690 lbs.

[mshelly]

No doubt headers work well, but what if we choose to keep the cast iron for reliability and noise?

Are there any improvements to be had in modifying the stock manifolds? Grinding, polishing, head-like work?

With all of the tweeks out there I can't recall ever seeing any discussions on this.

[dodge66500]

yes there is a company out there that does do work to exhaust manifolds just like head work it is called extrude honing i believe and i have this in prev mag i would have to dig it up .

Originally posted by mshelly:
No doubt headers work well, but what if we choose to keep the cast iron for reliability and noise?

Are there any improvements to be had in modifying the stock manifolds? Grinding, polishing, head-like work?

With all of the tweeks out there I can't recall ever seeing any discussions on this.

[BBMAN]

I've heard that extrude honing is very expensive for what you get. I think it is someting like 500 bucks for a set of manifolds and the finished flow is now where near a set of headers. But if your more concerned about keeping the outside of the engine looking stock, it may give a little hp gain.