Technical Equal-ish length salt flat style headers

I’m currently running cast Ram-horn style exhaust manifolds on my 1931 ford coupe on 1932 frame with SBC. I’m planning to set the car up for drag racing and am considering changing my exhaust to a tube header. If I can’t fit a tube header inside the frame, I’m considering my options for going outside the frame. I certainly like the look of a salt flat style “header” exiting at the cowl, but most of those 40s/50s style headers that I see are basically a log manifold. Do any of you know of a source for a equalish length header that exits near the cowl yet remains up high, without d****** down over the radius rods. I may be looking at a custom header, but I wanted to check the brain trust first.

 

The word “Lakes” headers always makes me laugh when they are the most un lakes thing ever when all they are bolt on do dad that makes your car slower.
If you really want a cowl exit header you will have more benefit with a shotgun style of each primary having some length to it.

The lakes headers cause a huge amount of back pressure and restriction and when you hear a car with them on they sound asthmatic, I would try to push for a full length tube header, I managed to fit 1 3/4” primary headers with long collectors onto a SBC in a model A ch***is. This car would run low 11’s all day long and i attributed that to actually having real headers.

there is a interesting engine masters video testing various novelty headers it’s worth a look.

 

Equal length is only a benefit if the length is tuned to the speed the engine is designed to run. For a street driven car running at 1,200rpm you want a 34" primary tube. For a 8,000rpm dragster, 16" is more desirable. For a Sonic cruiser I would be looking for a good looking header, more akin to the function of a manifold.

Chrysler did a bunch of work on intake and exhaust design and developed this formula to estimate optimal primary tube length.

L=(850×(180+BBDC))/RPM

Where:

• L = primary tube length (inches)
• BBDC = exhaust valve opening timing (degrees before bottom dead center)
• RPM = target engine speed
• 850 = empirical constant (based on speed of sound in hot exhaust gas ≈ 1300–1700 ft/s)

That constant changes to a lower number in intake manifold design since the speed of sound is slower in cooler gas.

 

Op has Two threads
Op plans a 383 with 200 of spray,
a mid 383 should be 500
I would look into 1-7/8 they are not true with out Stahl pattern, & I would use angle plug header's even not angle head used
Lemons , pics on other thread for in rail

 

What is the advantage of angle-plug headers? Is it for spark plug clearance?

 

Can you send more photos of your engine bay (especially the headers and related clearances) and perhaps the model number or application for the headers you used? Your info is super valuable to me along with your experiences.

 

Angle plug headers will give more Clarence for spark plugs on non angle plug heads

 

May need to break out the welder would like to find a pair of flathead outside the frame rail headers similar to my avatar

 

That's always my approach!!

 

I'll bet you can find something that will work here: Schoenfeld Headers Products - Schoenfeld Headers
You just have to open up your mind to the possibilities.

 

One of the best header designs around is the old Y type where two cylinders are Y together, then the final two pipes join into a collector. They fit in tight spaces, and tests have shown they flow as well as 4 equal tubes.

 

Thanks, I tried the Schoenfeld web site, didn't see any Flathead offerings

 

I don’t have a huge amount of photos, but here they were when I fabricated them, As I say 1 3/4 primary’s into a 3” collector roughly around 20” long, then blanking plates so it can run through a system. Motor was a 383 although stock 4” bore as the block was new so a 377” in reality, nothing crazy for cam or heads. Vac secondary carb, tri Chevy rear ended with with a welded 3.77 diff. And would run 11’s consistently, best was a 11.21 @ 118 and I would drive it to the track and back

 

Thanks for the response from each contributor, I'm running an 8-BA & only interested in an over the frame rail multi tube header as close as possible to my avatar in the photo, I'm using an F-1 steering gear so fairly straight forward, my intent is to retain the as raced outward appearance with only minimal deviation & realize some modification to the flow of the tubes might be required. Ron

 

How did this thread go from sbc to flathead ???

 

It began as salt flat type headers !