Considering manifolds

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Kenflo

Kenflo

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I am thinking about exhaust for my 340 stroker build and am considering the hi po remanufactured 68-70 340 manifolds. I will have the eddy aluminum heads, will there be any issues? I like the fact that they will be easy to install vs headers. Are manifolds a bad choice on a stroker?
 
My L.H. stock manifold would not work with Edelbrock heads, out of the box. Had to machine off some excess material on the bottom/outside edge of the head where it interfered. You'll see where the interference is if you mock it up before trying to bolt on the manifold.

Anyways, I think you'd be better of with headers, because as good as those stock manifolds are, they were never meant to flow what a 416 cu. in. engine needs at higher RPM.
 
i agree with GTS... why go to the expense of rebuilding and adding alum heads ttochoke it off with stock exhaust
 
Yeah I hear what your saying, if I did use the manifolds my plan was to use the tti 2 1/2" h pipe system with dyno max mufflers, so it wouldn't be necessarily a stock exhaust.
 
Stock manifolds will still be the cork regardless of what you put behind them.

Run a camshaft that's on a wide LSA, 112-114, if you must run iron manifolds.
 
I really like the way the new TTI shortys fit...
 
im going to check on these new tti shortys, they sure look like a good option. Any one else have them installed?
 
I had Hookers and 3" pipes to flowmasters, 2 1/2" out the back. It sounded some kind of good.
 
If you have the stock manifolds extrude honed they will flow nearly as well as headers. I did this on my stroker 273 and it worked well. Not totally sure about a 340-360 build.
 
dynodonn said:
If you have the stock manifolds extrude honed they will flow nearly as well as headers. I did this on my stroker 273 and it worked well. Not totally sure about a 340-360 build.
Click to expand...

Id like to see some flow data from the honer on that one before I would pony up the bucks. Headers use the exhaust pulses to scavenge the other pipes in an orchestrated dance, its not just square inches of exhaust (which the headers have 4 fold over any manifold). I know my 65's driver has a factory steering shaft pinch and a mean 90 bend at the end, although not as bad as the 383-A body ones. a 416 is 65% larger than a 273 and the manifolds are not that different between the 273/318 and the 360.
 
Ditto on data! Also before and after numbers wor be great. If anybody has that info? It would be great to know what (various) exhaust manifolds flow.
 
Extrude hone is expensive and provides marginal improvements. To do 2 manifolds is in the $800 range. They WILL NOT flow or work as well as a good header system.

Ask anybody that does FAST, if they'd rather have headers or modded factory exhaust from a pure performance approach.
 
I have only imagined the power increase with headers on those FAST engines.
A stock looking small block in the 11's with manifolds?!?!
WOW!
 
dynodonn said:
If you have the stock manifolds extrude honed they will flow nearly as well as headers. I did this on my stroker 273 and it worked well. Not totally sure about a 340-360 build.
Click to expand...

you will not see a difference doing that. waste of money . i talked to a F.A.S.T racer a few years who had it done. didn't do crap for him. he had back pressure gauges throughout the exhaust system too.
 
it sure would be nice to see some real world figures.
In the fast class D Didduck runs his 700 + hp road runner in the hi 9's through stock
2 1/2 " exhaust.
... there are a lot of grey areas in these exhaust theories.
 
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