Does anyone have any historical info on this intake? Seems to have mixed performance reviews but is unique and satisfies the LCES factor. None the less i will be running it on a mild 59 motor. Some have PM-7 embossed on them, this one does not. What is the difference? Any tuning considerations with the “ high rise” configuration?
That intake appears to be an earlier Thickstun. The PM-7 was a later design and had more rounder intake runners.
Here is a picture of a PM-7. They were produced after WWII. The earlier ones had been produced prior to the war.
Am running a repop on my 8ba. Getting good torque and mileage averages around 15. Expensive but I like the look of them. Have seen any special tuning characteristics. just use a unisys to even them up.
The thickstun is a cool looking intake but a very POOR performer. I have extensive dyno tests of a strong “mule” flathead running 10-12 diff intakes in Hot Rod mag. The diff from a thickstun and Edelbrock slingshot was 18 hp . That is about 20% on a motor(stock around 100 hp). If you want a thickstun just for “profiling” but if you want a better performing flat,the Edelbrock slingshot is a better choice. The best performing intake tested(no 4 carb intakes were used) was the 3-2 Navarro that made about 20 hp over the slingshot. Flatheads Forever!!
While dyno test on a “built” motor shows impressive results, I am skeptical that there would be the same improvement on a mild motor. I was interested in the historical aspect........
The PM-7 has a very cool historical factor. So by relation the early version intake should also be historical. And maybe even more cool. But the guys are right about it not proving to be a great performer. If you can stick your finger into a port and feel a square corner, it's not going to perform well. Air and fuel mixture doesn't want to turn hard corners. I have one of the Thickstun earlies, like yours, as well as a PM-7. I haven't installed either on a running engine yet. I am currently using an early Weiand hirise that has a couple hard corners in its ports. I wouldn't call it a top performer either. But it sure is cool, and by some accounts one of the first hirise intakes made (1939), so it is historical.
Hot Rod had a comprehensive write on the flathead intakes in their "Flathead Ford Intake Manifold Smackdown" article. It includes testing the Thickstun with the 2 carb intakes. The article has been condensed since its first posting. https://www.hotrod.com/articles/hrdp-1301-flathead-ford-intake-manifold-smackdown/ I made a PDF of the article that I attached as well if it is of some assistance.
Am I wrong or was the thickston developed by a guy that worked for Vic Elderbrock? Didn't he think he could do a better job? Just seams like I read this somewhere.
My suggestion would be to go to myflatheadford.com for a wealth of information on practically every piece of flathead speed equipment with lots of pictures . That's where I found out that my short Thickstun, which a number of folks on here kept saying was a cut down PM-7, was indeed a pre-war PM-6 and was more desirable than the PM-7. Look at the differences in the runners from yours to the PM-7. You may have something really rare.
Thanks Alan, I learned a bit more, as you suggested the prewar Thickstuns are few and far between. These are unique pieces far before the many that followed and surely before anyone had access to computer programs and dyno testing. It is obvious as pointed out by above post the design was evolving and this is not a race winner, seems like many are trying to build a fast Flathead, I’m satisfied with a good sounding solid driver, the nostalgic look using original parts is appealing...
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