headers verus manifold

[70challengerrt]

I've heard from several people and seen it on this site a couple of times that the stock high performance manifolds flow just as good as headers. Can this be true because headers help pull exhaust out manifolds do not? I am going off the assumption that the headers are not equal length tube(like race headers) but are average headers like headmen, dynomax, hooker.

[MEK-Dangerfield]

The HP manifolds are definitely better than the standard manifolds. I wouldn't say they flow as well as headers though. I was under the assumption the tubes were all equal length(on headers). The larger the diameter of the tubes, the more it was made for higher RPM's.


  Mike

[ShelbyDogg]

No, that isn't true.  How could it be.  Just look at the short runners and you'll see how you can't compare apples to oranges.  The only factory ones that came close, were the cast iron 413 max wedge manifolds.

[todd383]

on any stock high performance engine, headers will add about 10 too 15 horsepower,bigger cam, ported heads, better intake , more compression,  headers will dramadicly improve horsepower. Seen it on dynoes!!!!!

[Chryco Psycho]

with the correct cam design you can get great power from manifolds but headers will still make more power WITH the right cam choice as they have better scavenging which reall y is what fills the cylinders

[mrjack10]

http://moparmusclemagazine.com/techarticles/155_0307_exhaust/

[Rob C]

A most excceeelllent exapmle of how headers can help and why big tubes do not allways work best.
I'll say theose big Hookers like big power and 300 HP ain't it.
Add another 80 - 100 HP and retest. You'll see a big difference in power between them all.

Whats your combo like?

[70challengerrt]

I am up in the air about the combo and was going to post it for suggestions. I will be starting with my 75 440 cast crank block. I have a set of mid 1960s heads of a 413 which are closed chamber. everything else was a question. I am gathering stuff now and will pull the motor in fall and build up from there. I thought of the edelbrock package, or call in comp cams and have them reccomend a cam. I want something to run about 9.5 to 1 so I can run pump gas and even kicked the idea of supercharging and EFI around. centrufical of course because I don't want a hole in the hood. I was going to get the heads done with at least the bowls blended and may be a little porting. May be buying a new set of after market heads? I am looking for a respectible street motor that I can fill up at the local gas station, can lay a nice set of lines, and wont get blown by from kids in 5.0 mustangs and ricers. The tranny is a 833 OD and the rear end is a 3.54 Dana.

[Topcat]

Look at the numbers, the headers really show a difference only in the mid range HP

[Topcat]

I too have been debating whether I should go with headers or manifolds. But from what CP and I talked about last year together in Carlisle, I'll probably go with manifolds. I've done the header route before and became really irritated when they would develop a leak. Has anyone had any leaking issues with the TTI's? My past experience was...if it's a header, it'll eventually leak. And if it's a manifold...it won't.

[70challengerrt]

The worse part of headers is I almost have use TTI beacuse I have ps, pb, and an 11" bellhousing so I is tight.

[MEK-Dangerfield]

I too have been debating whether I should go with headers or manifolds. But from what CP and I talked about last year together in Carlisle, I'll probably go with manifolds. I've done the header route before and became really irritated when they would develop a leak. Has anyone had any leaking issues with the TTI's? My past experience was...if it's a header, it'll eventually leak. And if it's a manifold...it won't.

topcat,
   I've had luck so far with headers. There is a company called Percy that makes crushable gaskets for headers. You can feel them crush as you tighten the header bolts. I know Jegs carries their line of stuff. I would think as long as your block is not deformed, you can have success.  I understand headers being a pain in the arse though. 


  Mike

[HemiOrange70]

The results for the HP manifolds over the regular doesn't warrant the outrageous price difference. If you want extra horsepower get the TTI headers.

[Chryco Psycho]

the TTi on the Hemi is awesome , you will pay close to the same $$ for repro cast Hemi manifolds & with thye Hemi you cannot burn spark plug wires etc

[67Vette427]

I prefer the HP manifolds. Less install headaches, more space to get to the plugs, less clearance problems with the ground, less leaks, easier to pull the starter, a lot less problems than headers. Unless you get them coated you also have rust issues to deal with.