Just how important are street headers, really?

[digger]

comparing OEM requirments to those trying to build a high perfomance engine lol

[Tom68]

Most engines now especially the 4 and 6 cylinder ones don’t even have a manifold at all, it’s part of the head casting with a single hole for an outlet, typically with a 4 stud mounting for a pipe to bolt up. Always made me curious about how you’d go about porting one if you could at all.

They are really big inside and have good trailing vanes off the ports so you'd only need to work the seats and bowl.

[PackardV8]

Most engines now especially the 4 and 6 cylinder ones don’t even have a manifold at all, it’s part of the head casting with a single hole for an outlet, typically with a 4 stud mounting for a pipe to bolt up. Always made me curious about how you’d go about porting one if you could at all.

So the 1951 Nash OHV 6-cyl was ahead of its time. The exhaust outlets were curved to a 2" diameter pipe radius. The too-thin wall pipe had slots cut in it and was clamped to the head. They always rusted through.



jack vines

[tjs44]

JMHO,with a true street car from off idle to 3000 rpms,over rated.Tom

[lefty o]

does it matter, yes. is it truly a big deal on a street car, no. ford put that junk on there because they know 95% of buyers are likely to throw them away and put actual headers on. so why should they design a nice part, and all associated cost when they can just slap junk on, and sell the car for the same price.

[FC-Pilot]

I worked at the ford proving grounds in AZ a while back. I watched them test headers in stuff a number of times. Every time the engineers dealing with performance loved them. Why they did not have them when they were sold off the show room floor? COST SAVINGS. They still have building full of been counters back in Dearborn.

Paul

[juuhanaa]

OEM 4-2-1 and 4-1 marked using ballpoint pen. So you guys are saying that a hockey stick like what my mk1 consul had (before i trade it to datsun 1000) would make a street engine better till 3000rpm?

Screenshot_20221029-132748.jpg

Screenshot_20221029-125539.jpg

[juuhanaa]

I could do a pull till 3000. At 4000 it might bend the crank

[Tom68]

OEM 4-2-1 and 4-1 marked using ballpoint pen. So you guys are saying that a hockey stick like what my mk1 consul had (before i trade it to datsun 1000) would make a street engine better till 3000rpm?

Screenshot_20221029-132748.jpg


Screenshot_20221029-125539.jpg

No, but the way the heads were cut made modifications a racer only worthwhile proposition.
Rebuilt my Zephyr motor, bloody idiots, the engine mount bolts etc were not blind holes, put my bolts in dry and the seepage past the threads stained the beautiful Ford Blue paint job on the block. Still, another lesson learned and filed away in the knowledge bank.

[juuhanaa]

Most engines now especially the 4 and 6 cylinder ones don’t even have a manifold at all,

So the 1951 Nash OHV 6-cyl was ahead of its time.

1953 consul is a 2 valve 79.3 mm bore and 76.2mm stroke. Waay different than a undersquared 4 valve engines. To me, a street engine is one that we just show the key and go. Has a good idle, passes the inspections, has great overall torq and fuel mileage etc... Many of you probably already knew my example, but the point id poorly tried to bring up was: If it's already been beaten to death in racing, i don't see why it wouldn't work on the streets.

Ps: I dont know the tricks what comes to log manifolds (shorter primarys something). I noticed the link to a old thread though..

vappuna 2021, kuva 3.jpg

IMG-20210505-WA0067.jpg

-juhana

[Tom68]

vappuna 2021, kuva 3.jpg

Had to pull that passenger compartment air vent tube off the firewall on my Zephyr on hot days and point it at the fuel pump to stop it vapor locking.

[mag2555]

Here’s some older, but right off the dyno numbers.

[juuhanaa]

Whats the difference between 1 and 2?

[Tom68]

Here’s some older, but right off the dyno numbers.

So full exhaust system cut 20 HP off a 400 HP stock 455, goes along with no point running headers with an OEM supplied legal exhaust system.

[digger]

headers are fairly contrary to meeting current emmisions. not worth the hassle imo