Hot rod magazine article on testing popular flathead manifolds

[46fatford]

I just noticed that in the January 2013 isue of HOT ROD magazine that there is an article by H&H flatheads where they test 12 different current production manifolds. I found it interesting and thought I would share it on the barn. If you do not have that issue, you can go to the website and view it as well.
Matt

[4tford]

good article for sure.

[Ol' Ron]

They missed the Edelbroch and Offy super duals tho

[Dusters swe]

http://www.hotrod.com/techarticles/h...n/viewall.html

[Ol' Ron]

I still don't see the Edelbroch or Offy Super dual in the test??

[itsa52]

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Thanks for the link and heads up,, good article.

[JM 35 Sedan]

I was surprised to see the Thickstun PM7 2x2 did so poorly in comparison to other 2x2 intakes.

[Henry/Kokomo]

Thanks, Matt. Good article. Wish they'd dynoed a Merc. manifold and 2GC for comparison.

[Bruce Lancaster]

Edelbrock and offy supers do seem to be absent...I would bet money that those are the top two selling FH manifolds of all time, and popular also on racers before big inch strokers became normal. The su359 is probably the most historically popular manifold tested. Edelbrock current repro of the super dual was badly chosen, they picked the model with no bracket and no heat so that it will be a problem for most people, and I suspect that the Speedway iteration of the Offy has lost the two upper parts of the casting, though I'm not certain.
The Navarro super dual is visually much like the Edelbrock.
This is a VERY interesting article, and is going to need a lot of close reading!
Thickstun...I've always thought it was designed entirely with easy installation in mind. The hotter dual manifolds must have been nightmares for teenagers trying to install them on a Saturday...install, go back to store for generator bracket, find out the studs won't come out, back to store, break off studs, go weeping to a professional mechanic, buy lots more stuff, walk to work til next Saturday...AaaaaaRGH!

[Ford Flathead]

I could not bring every intake ever made, trust me my truck was loaded to the brim. I was on the dyno for 3 days and had to get back to work so I had to make some choices. I would have liked to test my Kong intake and some other 4x2 intakes but there was no time left. Plus we did do 90 pulls on my engine and figured it was enough. I do sell a good amount of the Edelbrock super duals but the Offy doesn't sell at all.

[Bruce Lancaster]

Thank you for making all this information available!
I would love to see a test of one of the 4 carb manifolds like Edelbrock that is close to an IR design. I've had a lot of discussion on this with people who ran them and the whole idea of the IR type approach is fascinating for an engine that is easy to over carb.
The old Offy Super dual was pretty tall, and each carb pad was obviously cast on from a separate layer of the molding apparatus. Looks to me like Speedway just eliminated that stuff and directly tapped the lower casting, lowering the whole manifold to almost the level of Fenton.

[richard rink]

Mike and H&H, this article is an outstanding contribution to determining what truly works. Thanks for the providing the numbers. This is the kind of testing is out-of-reach for most; it's a pleasure to know, after all the years of the flathead's popularity, that there is still much to learn about tweaking its performance. Richard

[Kahuna]

I think this is an excellent article, and agree that it would be nice to see more done with some of the 4 carb offerings. It seems that in all the tests, that the rpm/max power is around 4500-4700. I wonder if this is due to the cam chosen or that the engine could use more carburetion cfm. I'm thinking both

[my4dv8]

Great tech article from h&h very useful as a base line in selecting a manifold from the hundreds out there. Sure can even get close to testing even the ones that are the next most popular. But this gives a great start and who knows maybe someone else may pick up and follow on from the H&H Dyno runs.

[Bassman/NZ]

Back in the 60s a local hero had a single seater special that was flattie powered. It was bored, stroked, had all the tricks, and he was the NZ beach racing champion for a while. I asked him why he only ran a locally cast super dual type manifold on a big inch race engine, and he replied that he had tried many combinations, but the super dual type produced a seat of the pants improvement over all the other combinations he had tried. Interesting stuff.

[Bruce Lancaster]

A link for those who have not read this great article:

http://www.hotrod.com/techarticles/h...old_smackdown/

I'm going to buy a copy of the magazine, too! I ran out of reasons to buy HRM a long time ago, but they deserve a sale for printing this!

[Ol' Ron]

JWL's Book "Flathead facts" published in '04 had a similar series of dyno tests including the super dual.
I ;oke the old Offy superdual and used them on the hydro and Bivele engines. I bores them out for 2GC carbs. They have considerably more meat on them. Also you can use the late Holley 2100 (54/6) Pickup carb

[Yoyodyne]

Originally Posted by richard rink

Mike and H&H, this article is an outstanding contribution to determining what truly works. Thanks for the providing the numbers.

+1, lots of good data.

Anyone have information on how a Tattersfield manifold compares?

[Dennis Jarrell]

I can't believe it will much different than the Thickston. The runners are abrupt at the base.

[BillM]

Joe Abbin did some dyno testing comparing an Offenhauser 3X2 to a Weiand 4X2; pretty much equal for the 284 cu. in. engine he was using. Here is a link: http://www.roadrunnerengineering.com...terOct2010.pdf