Hot Rods Flathead Cam and Stroke choices

I'm in the process of building a new motor for a new project and have a few questions for the Flatty guys who have done it more than I have. I currently have a 1007B Isky in my 59a flatty in my 34 Tudor with great results and it's got a good sound and performs well. But in this new build I want a nasty sound that still performs well.
59ab Flatty 239 is motor in question. Aftermarket heads and intake, and mild porting etc.

Does the 4" stroke merc crank add that much in a noticeable gain to be worth the financial output for either a stock cleaned up or a Scat? I know on the stock figures that van pelt has its good for 10 hp on stock heads. Is the power and torque down low or more midrange focused?

Cam choices, I have a few buddies running 400jr's and they are pleased with them, but I have heard some Potovin 3/8 grinds online but I have known no one running one so I decided to turn to the hamb as someone here has to have run both cams and have a real-world experience between the two.
Thanks in advance.
Jesus likes flatheads too.

 

A couple of rules of thumb to consider first.

Two similar engines, all other items being equal, except the stroke will make the same peak power, but the engine with the longer stroke will do it lower in the RPM range. In fact, the entire power curve will just shift lower into the rpm range. The problem you run into, is that it is impossible to get all other things equal. A longer stoke will increase piston velocity, which results in changes in rotating resistance, dwell time, volumetric efficiency, and other factors which all have an effect on the power curve.

Longer stroke (and larger displacement in general), will dampen down a larger cam. I.E., a rowdy and knarly cam in a 250 ci engine will be much less so in a 300 ci engine.

Flatheads are the most expensive way there is to generate 200 hp. Because of the poor volumetric efficiency of the intake tract and associated low compression ratio, changes to stroke and cam, produce less gains than in a similar sized overhead valve engine. These are not necessarily bad things, just be aware that the biggest gains come from figuring out ways to increase air density within the cylinder.

 

i ran a 400jr in a shoebox and it was a terror in 2nd gear from 40mph and up. dead as a doornail in town. i'd use at least 4.10 gears. oh, and check your cylinder head clearance over the valves. an 88 might be a better choice...

 

Look into an L100. There are several sources, and I have heard good things.

 

The L100 sure has the sound thing figured out. Not sure about the rest, but I 'd love to find out.

 

If your just wanting a cam to make some noise check out the Mutha Thumper from Comp Cams. I saw a video of an 8BA running with one and on surround sound with the volume turned way up it rattles pretty good! The dogs were howling and yowling, the wife was screaming for me to turn it down so it’s got to be a good’un

 

Well where is that video?

 

One of the best sounding flatheads I’ve ever come across but this is with nitro. There was another from Honest Charley with one on a test stand. Can’t seem to find it now. Hoping my 1007B cam will be “good enough”. lol!

 

https://www.jalopyjournal.com/forum/posts/12466630/
TheL100 cam now made by @KiWinUS isn't called the smiley for no reason . Excellent low end torque and on our 3w with the doors open it looks like it will fly.

 

My 59L w 4" merc crank and L100 sounds great and moves my coupe pretty good. I'm running 10s flat in the 1/8th mile.



My coupe at 24:24

 

Damn, that sounds and runs great!

 

I’ve got an L-100 from Kiwi sitting on the shelf. Can’t wait to build a flathead around it.

 

Long and lumpy would be my choice.

 

Fun little find that I found today on the barn.

 

I had frames on here build my current FH motor. Scat 4 inch crank and Isky 88 cam. 2 carb intake. Sure ran good on the test stand.