340 headers vs. factory manifolds

[priderocks]

I am putting a mild (350) hp 340 in my 70 cuda. I have a set of the original hp exhaust manifolds. Should I use those or spring for headers? Street driving only. How good or bad are the original cast iron manifolds compared to a good set of headers?

[Chryco Psycho]

What do You want ??
 Factory manifolds are ok but will trim some power , headers can be a pain unless you are willing to spend the $$ on Good ones like TTi or Dougs
 I generally pick the cam around this choice as well so what cam is in it ?

[challengermaniac]

No question as far as what I would and will be doing with my 340-------- stock exhaust manifolds are going on once they have been blasted and heat painted.  I absolutely love the stock look and don't have to worry about header exhaust leaks and little dents, etc. 

Charlie 70 Challenger
69 Camaro RS

[Chryco Psycho]

There is no correct answer here just what you want & what works best for what you want

[Super Blue 72]

Good points made above but also depends on how you want the car to look.  If you are making the car to look purely stock, the sacrafice in HP may be worth it for the factory look. 

It's just my opinion, but if I see a car that is "purely" stock then they pop the hood and I see headers, it really takes away from the factory look. 

[HP2]

Here's a good read for ya.

http://www.moparmusclemagazine.com/techarticles/engine/mopp_0307_mopar_crate_engine_exhaust/index.html


Try this one.

[sadil340]

http://www.moparmusclemagazine.com/techa...aust/index.html

HP2, thanks for the link but it doesn't work

[71chally416]

Here's a test that shows exactly what you give up when you bolt those old cast iron manifolds on a stock 340. The ones they they removed were the supposed "Good" ones and there were no tailpipes to further restrict the flow.
http://www.compcams.com/Community/Articles/Details.asp?ID=-738676943

[moper]

If you have 318 stockers, go with headers. If you have 340 stockers from a 70-71, they are considered the good ones. But, they are still only the best factory manifolds. And headers of any sort will make drastic improvements over them. But, lots of people have other considerations for not running ehaders. The end choice is the owner's, really.

[Alaskan_TA]

Best ET: 11.57 @ 123 MPH through the manifolds;


http://www.fastraces.org/members/fastraces/fastraces.nsf/00000000000000000000000000000000/0a9b33b9ae13f00e8525728f00424bf8!OpenDocument

[71chally416]

Sure, with 416 cubes, 12.5 compression and a .630 lift roller cam  You can bet the heads are far from stock too and even those manifolds are extrude-honed. In that class all that matters is that the motor "Looks" stock from the outside.

[Alaskan_TA]

You missed my point completely. 

If manifolds allow those times with that set up, they are good enough for me as is with the factory CID & no mods.

Especially since I hate headers on a street car. 

[71chally416]

So ya think that's real fast, huh?

I just took a look at this weeks NHRA race. Guess who sits as low qualifier after 4 rounds in Super Stock?

Friday

Order for Qualifying Round 4

COMMERCE, Ga. - SUMMIT FastNews - Final order after 4 rounds of qualifying in Super Stock at the NHRA Full Throttle Drag Racing Series, 29th annual Summit Racing Equipment NHRA Southern Nationals:
 Psn  Driver                   
   1. Lloyd Wofford  Lloyd Wofford, Jonesboro AR, '78 Volare  SS/JA  Class Index - 11.30 ET- 9.966 - Ov/Un 1.334
It's either a 318 or 360 (Don't think it's a slant 6....), but it sure don't have the stock exhaust manifolds.   That T/A wouldn't even be legal to run NHRA Super Stock because it doesn't have the factory cubic inches. It would run Comp Eliminator where the respective records are even lower and it wouldn't even qualify.

Everything is relative. 

[Alaskan_TA]

I give up, you win, every street car should have headers, no exceptions.


































 

[HemiOrange70]

http://www.moparmusclemagazine.com/techarticles/engine/mopp_0307_mopar_crate_engine_exhaust/index.html