The Ford Barn

Junknshit · 12-26-2011, 06:59 PM

Have any of you flathead builders messed with intake runner length comparisons? Curious about what a basically stock engine with a couple 94s likes versus say L100 cam and a couple of 94s both engines stock valve size with headers and stock weight flywheel.

38 coupe · 12-26-2011, 07:37 PM

The only way I know to experiment with runner length tuning on a flathead is to use an independant runner injector like a Hilborn and run different length velocity stacks.

Flathead · 12-26-2011, 09:28 PM

Different length runners will "come in" at different RPMs. Longer runners for lower RPM, shorter for higher RPM.

Junknshit · 12-27-2011, 06:39 AM

Thanks for the replies. What I was trying to find is a starting point, like say 6" or something for intake manifold runner length. I am building two manifolds and one of them will be for 4 single barrels (that is why I used 2 X 2 example) each one for two cyls. 3/8ths flat plate with tube runners. Second one is old alum. manifold that someone ruined years ago the way it looks. Cut top off to expose all ports and am going to put open chamber box on it with two progressive 2 bbls off of Toyotas. They work like a 4 bbl. Cruise on single and open second for power. Probably removable top so could change to three carbs for bigger flathead later. Don't ask me why, just playing around. Guess I've got more time than brains.

JWL · 12-27-2011, 07:25 AM

If you read my book you will see examples of increasing runner length and the value at various RPM during tests.

Junknshit · 12-27-2011, 08:06 AM

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JWL, I am sure that if I read your book I would probably learn much more than just runner length, and I do plan on having it some day as well as Ol' Rons book. My problem is I live on Soc. Sec. only, so 50 dollars for your book doesn't come easy. I am saving towards getting both books right now.

I have a son that works at a metal and welding supply and fab shop so I get my metal free from their scrap, and that allows me to play around with this stuff now. While I am sure that one of my sons would buy the books for me if I asked, I will not do that because they all already do more for me than I really like them to.

When I do get your book, I'm sure that I will still be asking questions here, or someplace else. Just my nature to be curious about things that I don't know. Figure what I learn, I can pass to my sons and their buddies and keep it known for another generation. Any books and literature that I have, as well as my notes will be passed on also.

12-26-2011, 06:59 PM	#1
Junknshit Banned Join Date: Oct 2011 Location: Wash. Posts: 233	59AB intake runners? Have any of you flathead builders messed with intake runner length comparisons? Curious about what a basically stock engine with a couple 94s likes versus say L100 cam and a couple of 94s both engines stock valve size with headers and stock weight flywheel. Last edited by Junknshit; 12-27-2011 at 07:27 AM.

12-26-2011, 07:37 PM	#2
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 1,648	Re: 59AB intake runners? The only way I know to experiment with runner length tuning on a flathead is to use an independant runner injector like a Hilborn and run different length velocity stacks.

12-26-2011, 09:28 PM	#3
Flathead Senior Member Join Date: May 2010 Location: Southern Maine Posts: 1,502	Re: 59AB intake runners? Different length runners will "come in" at different RPMs. Longer runners for lower RPM, shorter for higher RPM.

12-27-2011, 06:39 AM	#4
Junknshit Banned Join Date: Oct 2011 Location: Wash. Posts: 233	Re: 59AB intake runners? Thanks for the replies. What I was trying to find is a starting point, like say 6" or something for intake manifold runner length. I am building two manifolds and one of them will be for 4 single barrels (that is why I used 2 X 2 example) each one for two cyls. 3/8ths flat plate with tube runners. Second one is old alum. manifold that someone ruined years ago the way it looks. Cut top off to expose all ports and am going to put open chamber box on it with two progressive 2 bbls off of Toyotas. They work like a 4 bbl. Cruise on single and open second for power. Probably removable top so could change to three carbs for bigger flathead later. Don't ask me why, just playing around. Guess I've got more time than brains.

12-27-2011, 07:25 AM	#5
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: 59AB intake runners? If you read my book you will see examples of increasing runner length and the value at various RPM during tests.

12-27-2011, 08:06 AM	#6
Junknshit Banned Join Date: Oct 2011 Location: Wash. Posts: 233	Re: 59AB intake runners? Sponsored Links (Register now to hide all advertisements) JWL, I am sure that if I read your book I would probably learn much more than just runner length, and I do plan on having it some day as well as Ol' Rons book. My problem is I live on Soc. Sec. only, so 50 dollars for your book doesn't come easy. I am saving towards getting both books right now. I have a son that works at a metal and welding supply and fab shop so I get my metal free from their scrap, and that allows me to play around with this stuff now. While I am sure that one of my sons would buy the books for me if I asked, I will not do that because they all already do more for me than I really like them to. When I do get your book, I'm sure that I will still be asking questions here, or someplace else. Just my nature to be curious about things that I don't know. Figure what I learn, I can pass to my sons and their buddies and keep it known for another generation. Any books and literature that I have, as well as my notes will be passed on also.