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Can I use my 383 HP exhaust manifolds on my 440 aluminum heads straight plug?

bigmanjbmopar

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Since headers are such a pita with power steering etc, and the fact that the HP manifolds give just as much performance as headers why not use them? I suppose bolts instead of studs is what I would be using but is the fit right? can 383 manifolds fit on a 440? anyone have pics?
 
Yes, they interchange and no, they don't perform as well as headers but, they're pretty close in some cases if you're using stock intake etc. I know every car that I used headers on performed better even if it retained the stock intake, cam etc and are always better than the log style manifolds.
 
Make sure though to use a really good exhaust gasket when using the HP's with Aluminum Heads. My 383 has Aluminum Heads and the HP Manifolds. So...I used the "REMFLEX" Gaskets because of the "dissimilar" metals...AL verses Cast Steel/Iron. Sealed up really nicely with no leaks....
 
Well nothing stock on my 440 except the iron in the block lol. According to the experts the HP manifolds have just as much performance value as headers, but assuming that is with an all stock motor.

I'm only looking at from a fitment perspective, but wondering how much I will loose or even notice if I did put the HP's on my 440. Were do you loose it it? low end? mid? or with a stroker like mine would I even notice a difference?
 
There is a thread about headers versus stock ex manifolds on the 66 to 70 mopars section of this forum. I went from HP ex manifolds to headers at the same time I went from 906 to 915 heads, and gained almost a full second in the 1/4 mile. I'm sure part of the power increase was due to the head change, and part was due to going to headers. Yes headers are going to out perform ex manifolds. Below 3000 RPM there may not be a lot of difference, but above that there will be. Oh, and the car with ex manifolds had open exhaust, as with the headers it did too.

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This was on a 451 stroker. Bigger cubes needs more flow on intake and exhaust.

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Both 383 and 440 can use the same ex manifolds.
 
It will suffer at high rpm. If you go that route run an exhaust crossover to make your exhaust scavenge as much as possible.
 
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