Re: Let's build a drag race 8BA engine One more time :)
I didn't read the whole 2nd page! I now know that it 11 lb per CI, right? First a FH will put out more HP per CI, the smaller it's displacement. The ports are the limiting factor, they are only 1.312, in diameter. You can increase the size a with a high level, grinding effort but the middle area is the most difficult and much harder to make consistent. Bigger intake valves won't do much w/o opening that port. It was mentioned to use 239 CI and 2629 lb so I have a suggestion. I'm building a 21 stud at 3.142 (.080 over) and I'm going to have a 59A crank offset ground to 3.85 stroke, equaling 239 CI. The stoke isn't so much for CI but, much more to increase the CR, using my Victor compressed thickness of .060. I goes like this: 1/2 stroke = 1.925 Rod = 7.00 CH of piston = 1.53 ------------------------ 10.455 Block 10.437 Head gasket = .060 -------------------- 10.497 -10.455 --------- 0.042 piston to head clearance with FT pistons and heads. You can juggle the dimensions any way you want, such as different head gasket thickness, stroke lengths and CH's But, what ever you do, get that piston as high as you can w/o getting under .036 clearance. |
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Ronnieroadster |
Re: Let's build a drag race 8BA engine Thanks Ronnie, hope you have fun at Bonneville, wish we were there.
Lawrie |
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I made cap supports sort of like that for 9" ford rears that fit in stock housings before aftermarket cases were plentiful, with through bolts and a flat machined on the cap and .001 squeeze fit. |
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This question is more for Pete and Kiwi.
I have a high end dyno sim. I had already run it with my above 21 stud info, using a 59A cam. I estimate that I will be able to get at least 9.2 CR out of it so, I changed out the cam to Howards 260 @ .050 x .440 lift cam on a 110 LSA. With that I got 239 hp @ 5400 and 255 lb ft @ 4400. I then advance the cm 5 deg and got, 237 @ 5400 and 258 lb ft @ 4000. Note that the advanced cam, gave 3 more average hp and 4 more average TQ. The program gives you a flat head block to start with, I added a 1.6 exhaust valve to it but, left the intake alone because it's hard to make improvement with it. Headers where as short as I could make them, to have a realistic exhaust. 14.4 primarys and 3.2 collector. Not ideal, I know. What do you think about the HP / TQ and rpm levels? |
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With a good car, you should be able to flat foot it all the way. |
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Cheers Tony |
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I'm with you on this, Tony. Those numbers seem really optimistic. There is book written by George Nichols (I believe) and he uses a similar dyno program. Every cam he put into the program had the motor making 200+ hp. I would check the specs on the Howard cam as well. Potvin Eliminator was at .425" and that is pretty radical cam. Howard's were not known for making radical stuff like Potvin. Crane or Isky's 404A. Many of the builders on this site would be doing back flips if it was that easy to make those numbers. |
Re: Let's build a drag race 8BA engine Thanks Tim. Besides my KiWi-L100 I have a Potvin Eliminator master so can grind & I Have original 404A NOS & nice used but with these sweet cam plus others in my collection ( we all know there’s way more to this than cams. These numbers are. To put it nicely Interesting.
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Re: Let's build a drag race 8BA engine Today's trivia lesson.
Howard Johanson (Howard's Cam's) was a neat guy that drank beer from quart bottles. |
Re: Let's build a drag race 8BA engine I forgot to add to my specs, that it had 3, 165 carbs (495 cfm @ 3" Hg).
I'm not so interested in the actual HP, but, more the peak rpm, for both hp and tq, as well as what the 5 deg advance does, to the average hp & tq. Tim, the cam lobe specs are accurate. It's Howards top duration and lift profile for the FH. The lift and duration, is a product of lifter diameter and the maximum lift velocity for that size lifter. SBC, .842 lifters, lift velocity, isn't even in the same universe as a 1" flat heads lifter. If you were to use these Howards FH cam profiles, with a 1.6, or greater rocker arm, you have valve events, that will beat some roller cam profiles. |
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The lift figures of that Howard cam are very similar to ones used by the DO Hal for mile track events. |
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As I said, I'm not building that engine. It was just food for thought, regarding what could be done with a smaller cube (higher hp per CI) engine, in a light car.
I just added the cam profile and 3 carbs, to my high compression 239 CI, 21 stud engine. This is what it predicted my 239, single carb (165 cfm), 9.2 CR engine, 1.6 ex valve would do, with a 59A cam. I don't think it's to far out of line for the CI & CR. What would you expect form a 9.2 CR 59A, with a larger ex valve? |
Re: Let's build a drag race 8BA engine If you 're talking about ANY cast crank, I would steer real clear ! What's wrong with the Mercury 4" crank. Nothing ! ! It is a superior piece. Rods.... Ford 8BA rods, polish side beams, have them resized, new bushings. These factory rods are a lot stronger than folks give them credit for. Best of luck. I 'mdown here in South Carolina, be looking for your car inthe near future !
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Re: Let's build a drag race 8BA engine You can purchase a very simple main cap support from Speedway Motors, I'd also install ARP rod nutz too. Install a cam with at least 400" lift, Isky 4 00Jr. or Potvin 425 are some good choice. Ues, relieve the block about 100 thousanths of an inch, install Chevy race type valves, 1.60" intales and 1 .50" exhausts. And first and foremost, check for cracks in your block, especially around mains to block, and valve to bore.
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Re: Let's build a drag race 8BA engine What !!!!! Unless you can machine off a good chunk from your heads, that'sthe only way to gain more compression on a Flathead. The pistons ARE what gives you the compression. And most off the shelf heads, including Edelbrocks, will only get you about 9.5 to 1, with a slightly domed pistons. Flat tops might give ya, uhhhhhhh, 6 to 1.
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Re: Let's build a drag race 8BA engine Maybe Ohio Cramkshaft, Speed O Motive used to be good, I think they are gone ???? With all thoseshops in NC, nobody can take a Merc 4" crank andstroke to 4 1 /8 th. Scats forged steel cranks are really expensive, and I would run away from any cast crank, dont care whos name is on the box.
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Re: Let's build a drag race 8BA engine Where not the stock ford cranks cast?
Lawrie |
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