500hp 408 with Hi-Po 340 Manifolds?

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jake17201

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Think its possible? I already have TTI's but just love the stock look with the early style manifolds. I plan on using hydraulic roller cam, rpm air gap and RHS heads. Just wondering if it would still be streetable in a daily driver automatic cuda. Open to suggestions!
 
I'm a big fan of the Hi-Po manifolds,however I believe your expectations are a little high for them. I say go with a nice set of headers for that 408.
 
I like magic tricks.
500HP through those old style butt plugs would be a good trick.
 
I think you would max out flow at around 4500 rpms that's leaving a bunch on the table... ok if your buiding a tractor.
 
...it would be very interesting to dyno both headers and early hi flo manifolds and see how much is lost.
 
theres an article on the hughes engine website thats a good read, under tech articles - #10 stroker test

they built a stroker for a lil red express while trying to retain the stock look , using the cast intake and stock manifolds...then a second test with TTI headers...the horsepower difference was around 50 horses gained

sorry 340 fastback....shudda checked your link..noticed it after i posted
 
..that is a great read 340s
the early 68/9 manifolds were very respectable giving up about 30 hp on a 475hp stroker and that would shrink some more through exhaust pipes and mufflers.

..the 360 logs,not so good.
 
Bill Dedman said:
http://tinyurl.com/cebd32g

Headers are far better...
Click to expand...

Yep they sure are if you like replacing blown gaskets all the time , header bolts that loosen up, clearance and heat soak problems with starters, oil filter clearance issues. having to snake most brands around the steering centerlinks, cooked idler arms, problems with spark plug wires melting, and having problems with spark plug installation clearance issues, rusted out tubular pipes, collectors bottoming out, Yep definitely better if you love these issues LOL

I have had headers before i f##king hate them. I just got a set of the 68 to 70 hi hi Po A body exhaust manifolds. The right side is similar to a header and they have large outlets. These are designed for flow.


The article from tti was with 78 dodge truck stock exhaust manifolds, with 2"exits. They may be from a LRT, but are a common as dirt stock 318 /360 pickup truck exhaust manifold. Id like to see a set of those numbers with a stock set of 68 A body hi po manifolds. But since tti did the testing, to arguably make their product look better, why not use the most restrictive stock exhaust manifolds you can find, and make the numbers look as good as you can compared to stock.

Im sure the tti pipes will flow better than a set of stock A body 340 manifolds, but how much more is the question? For me i prefer no blown gaskets, loosening bolts, hard to get to spark plugs, problems with pipes hitting my starter, or having to use a mini starter just so i dont end up with heat soak and a car that wont start when the headers toast the starter, as well as the idler link bearing cooking out from the heat.

I will take my chances with a bit less hp on my stroker 318 and run stock 68 to 70 A body hi po manifolds, and not have any of these headches. I believe the person who started this thread was asking about flow of the A body hi po manifolds not restrictive mid 70s pickup truck manifolds. I know headers flow more but are they really worth the hassles i mentioned?
 
Have any of you head of Jeff Patterson. He runs in Fast Class. He is making over 600hp with manifolds and stock intake. There is a video on You Tube of his engine on the dyno. I have heard his motor run. It doesnt sound like a race motor.
 
You buy cheap headers you have problems. Doug's TTi no problems
 
moparmat2000 said:
Only if you like wrenching on your ride with blown headr gaskets.
Click to expand...

moparmat2000 said:
More headaches with headers.
Click to expand...

moparmat2000 said:
Yep they sure are if you like replacing blown gaskets all the time , header bolts that loosen up, clearance and heat soak problems with starters, oil filter clearance issues. having to snake most brands around the steering centerlinks, cooked idler arms, problems with spark plug wires melting, and having problems with spark plug installation clearance issues, rusted out tubular pipes, collectors bottoming out, Yep definitely fpipesar better if you love these issues LOL

I have had headers before i f##king hate them. I just got a set of the 68 to 70 hi hi Po A body exhaust manifolds. The right side is similar to a header and they have large outlets. These are designed for flow.


The article from tti was with 78 dodge truck stock exhaust manifolds, with 2"exits. They may be from a LRT, but are a common as dirt stock 318 /360 pickup truck exhaust manifold. Id like to see a set of those numbers with a stock set of 68 A body hi po manifolds. But since tti did the testing, to arguably make their product look better, why not use the most restrictive stock exhaust manifolds you can find, and make the numbers look as good as you can compared to stock.

Im sure the tti pipes will flow better than a set of stock A body 340 manifolds, but how much more is the question? For me i prefer no blown gaskets, loosening bolts, hard to get to spark plugs, problems with pipes hitting my starter, or having to use a mini starter just so i dont end up with heat soak and a car that wont start when the headers toast the starter, as well as the idler link bearing cooking out from the heat.

I will take my chances with a bit less hp on my stroker 318 and run stock 70 A body hi po manifolds, and not have any of these headches. I believe the person who started this thread was asking about flow of the A body hi po manifolds not restrictive LRT manifolds. I know headers flow more but are they really worth the hassles i mentioned?
Click to expand...


But how about with a set of headers ? LOLOLOL
You don't like them. I get it.
The first time.
The FAST guys extrude hone the manifolds , coat them inside and out and yes......they get amazing numbers.
If you have your heart set on manifolds , that would be the way to go.
But how much horsepower would they make with a set of equal length stepped headers....maybe throw in a merge collector as long as we are going whole hog ? I'd be curious to see.
Bottom line , good headers make more power.
It's up to you as far as what you are willing to put up with , but they do not all leak , burn gaskets , heat soak your starter or give oil filter clearance problems. Good headers cost good money , and for many they are worth it.
 
moparmat2000 said:
Yep they sure are if you like replacing blown gaskets all the time , header bolts that loosen up, clearance and heat soak problems with starters, oil filter clearance issues. having to snake most brands around the steering centerlinks, cooked idler arms, problems with spark plug wires melting, and having problems with spark plug installation clearance issues, rusted out tubular pipes, collectors bottoming out, Yep definitely fpipesar better if you love these issues LOL

I have had headers before i f##king hate them. I just got a set of the 68 to 70 hi hi Po A body exhaust manifolds. The right side is similar to a header and they have large outlets. These are designed for flow.


The article from tti was with 78 dodge truck stock exhaust manifolds, with 2"exits. They may be from a LRT, but are a common as dirt stock 318 /360 pickup truck exhaust manifold. Id like to see a set of those numbers with a stock set of 68 A body hi po manifolds. But since tti did the testing, to arguably make their product look better, why not use the most restrictive stock exhaust manifolds you can find, and make the numbers look as good as you can compared to stock.

Im sure the tti pipes will flow better than a set of stock A body 340 manifolds, but how much more is the question? For me i prefer no blown gaskets, loosening bolts, hard to get to spark plugs, problems with pipes hitting my starter, or having to use a mini starter just so i dont end up with heat soak and a car that wont start when the headers toast the starter, as well as the idler link bearing cooking out from the heat.

I will take my chances with a bit less hp on my stroker 318 and run stock 70 A body hi po manifolds, and not have any of these headches. I believe the person who started this thread was asking about flow of the A body hi po manifolds not restrictive LRT manifolds. I know headers flow more but are they really worth the hassles i mentioned?
Click to expand...

I put a set of TTI headers on my 360 Magnum-powered '72 Valiant more door in 2003, which is Vortech supercharged, and made something like 445 rear wheel horsepower, which is not much, but the TTI exhaust system has never given me a minute's worth of trouble in that ten years...

Not all headers are created equal, apparently... You get wht you pay for, apparently.

Just my 2-cents.
 
dyno test with 340 and magnum manifolds

http://www.moparts.org/Tech/Archive/exhaust/9.html

looks like 30 plus hp loss with manifolds over headers which is about 3/10 in the quarter which you should feel in the seat of the pants

I also agonized over the headers/manifolds decision and am running a 68-71 left 340 manifold and a r/t 360 magnum manifold with the 2 1/4 (92-93 only) outlet on the right side. I agree with moparmat2000 though, I will eat the loss as I want a street car with MINIMAL FRIGGING
 
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