headers vs. manifolds

[opie_803 14]

i was following a thread on mustangforums about headers vs. manifolds on a 289 hipo and it got me thinking. i had headers on my car when i first got it but they were rusted out. having clearance issues with my driveway, i went with the stock manifolds when i replaced them.

 

i guess my question is am i loosing much hp with the manifolds over headers? i have the 4v heads and manifolds. the ports on both are very large and are matched. the headers that came off had a much smaller round hole to match up to rectangle port. it didnt seem as though it would flow very well.

 

long tube headers drag the driveway when i pull in and out. would there be any advantage to shorty headers (if made) over the stock manifolds?

 

thanks for your thoughts

[S code 69 13]

I'm not up on small blocks but on the big block mopars I work on the headers give about 14 HP on the dyno over the stock HP manifolds. now on a small block I'd expect a much smaller difference but on the other hand mopar HP manifolds are very good ones.

 

I hate headers and always have so my cars along with the 390 in my Mach 1 have stock manifolds, I guess as you've already figured out headers are a pain in the butt but if you want max output they are an advantage.

[Grabber70Mach 107]

Agree LT's can be a pain in the rear. I have been running these http://www.sandersonheaders.com/index.php?cPath=21_24_42

no worry about dragging. Not as godd of flow as the LT's but better than the stock manifolds in my application. I have no hard numbers just went on the advice of my engine builder to at least run these over the stock manifolds.

[NJ_Bob 10]

i was following a thread on mustangforums about headers vs. manifolds on a 289 hipo and it got me thinking. i had headers on my car when i first got it but they were rusted out. having clearance issues with my driveway, i went with the stock manifolds when i replaced them.

 

i guess my question is am i loosing much hp with the manifolds over headers? i have the 4v heads and manifolds. the ports on both are very large and are matched. the headers that came off had a much smaller round hole to match up to rectangle port. it didnt seem as though it would flow very well.

 

long tube headers drag the driveway when i pull in and out. would there be any advantage to shorty headers (if made) over the stock manifolds?

 

thanks for your thoughts

 

The shortys should be better than the long tubes but you won't get the same performance. You could try having the cast iron manifolds ported & polished for better air flow.

[mcode 10]

those look great -does any one know if those shorties would fit with a tcp power rack on a 70 mach 1

[Jayru 17]

I have long tubes on my car... and i agree, LT Headers suck! They get in the way of everything and are a pain in the ass to install! Especially if your car is a manual gearbox (Z bar, etc.)

 

I once had a Supercharged 5.0L that made 560hp at the rear wheels with unequal length shortys!

 

If i didn't already have the LT's (came with the car), and didn't want to spend more money on a new set of shortys and re working the exhaust, i would have shortys on my car!

 

I'm not sure since you have a 289, but you can get good flowing/quality shortys for 302's from companies like BBK for about half the price of the ones Grabber posted. (is it the same port/location on a 289 vs 302 heads?)

[grendi 16]

the CamQuest simulator software from CompCams might give you an impression of the power you would gain with headers.(http://www.compcams.com/CAMQUEST/)

 

unless you run a hot cam, you problably don't loose a lot of power with your manifolds.

[69gmachine 15]

LTs are always going to be harder to install than manifolds, but there is no reason for them to be dragging the ground. You will have to step up to one of the higher end header companies, but they will fit better all around. Don't whine about the price... you get what you pay for. If you get them ceramic coated they'll last a long time and look good too. For a NA engine, they can improve the torque curve everywhere as well as the top end power. However, as Grendi pointed out, how much HP/torque you will gain really depends on the rest of the engine. If it's not designed to produce over 300 HP, I doubt you will see any difference. If it's designed for 450 NA, I don't think stock manifolds will get there.

[opie_803 14]

thanks for yalls input. if it gets to where i am needing better flow, i will look a the sanderson headers as an option. i like the way they look and the size tubes used. i should be getting my new heads on in the next week or two and i will see where i need to go from there.

 

thanks again.

[jmlay 80]

A set of these will not scrape the ground like what you have had before, thy fit high & tight.:

 

http://fordpowertrain.com/FPAindex/Mustang1.htm

 

Mike

[mcode 10]

Hey grabber what tyranny did you use with the sanderson FC4 header --was it a aod and were you power steering

[Grabber70Mach 107]

First it had a C6, now it has a AOD in it. Just need to finish up the TV cable and shifter linkage to get it going again. It does have Power steering.

[opie_803 14]

jmlay, those are some really good looking headers to.

[bnickel 10,004]

it's expensive to have done but you could always hand port the stock manifolds and then have them extrude honed, all the guys in the F.A.S.T. racing series have to use stock manifolds so that's how they run theirs. i'd say that on cars that are running as low as 10.50's that they aren't losing a hell a lot of power by having to run manifolds. that's pretty much what i plan doing to my stock manifolds too.