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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Yoyodyne said:
Very clever setup, I wouldn't have thought of going through the pan with fasteners.
Do you modify the main cap for a seat for the bar, or just have it bear on the spotface areas for the main bolts? Where are the 5/16 bolts located and how are they used?
I'll never do this to a flathead, but I might be able to apply it elsewhere.

Thanks for the description!
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The support bar sits directly on top of the main bearing cap. The central area of the cap is machine flat this is a rather wide and long area for support. The bearing cap area where the bar sits is machined to a specific height so I can interchange parts between engines if needed. The bar sits high enough to clear the stud, washer and nut assembly's holding the bearing cap to the block. To clear the studs holding the cap in place clearance holes are required in the bar.
Ronnieroadster
 
Ronnieroadster said:
The bar sits high enough to clear the stud, washer and nut assembly's holding the bearing cap to the block. To clear the studs holding the cap in place clearance holes are required in the bar.
Ronnieroadster
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Oh I get it, the cap studs don't hold the bar, the bar is above and goes over top of the nuts. I assumed it would be all bolted together by the main studs/bolts. Nice.

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.
 
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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frnkeore said:
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?
Click to expand...

On a 1/4 mile dirt track I would gear it to run from 4000 to 6100.
With a good car, you should be able to flat foot it all the way.
 
frnkeore said:
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?
Click to expand...
Interesting but I believe those numbers are light years off. As Pete has eluded to numerous times the flathead can be organized to make good power but it comes at a large cost. Your simulated engine sounds like just a home built hot rod engine. The engines my boss built several of for the great American race were expensive 3.5/16 x 4.250 ported balanced good rods 1.6 valves great ignition single 48 Stromberg with phenolic spacer. Very detailed internally. 145hp. 2 carbs 165hp real dyno numbers. The stainless headers on his 40 coupe with this engine & been in TGAR. are spectacular looking. I have driven this car @ 110mph & still pulling strong. Electronic corrected speedo for race. It will pul from 30 mph in high gear but at 65 mph it sits you back in seat & throbs. These are ligit dyno numbers at crank. Not “happy dyno numbers” now these engines could drive across the great USA & back several times with zero issues.
Cheers
Tony
 
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KiWinUS said:
Interesting but I believe those numbers are light years off. As Pete has eluded to numerous times the flathead can be organized to make good power but it comes at a large cost. Your simulated engine sounds like just a home built hot rod engine. The engines my boss built several of for the great American race were expensive 3.5/16 x 4.250 ported balanced good rods 1.6 valves great ignition single 48 Stromberg with phenolic spacer. Very detailed internally. 145hp. 2 carbs 165hp real dyno numbers. The stainless headers on his 40 coupe with this engine & been in TGAR. are spectacular looking. I have driven this car @ 110mph & still pulling strong. Electronic corrected speedo for race. It will pul from 30 mph in high gear but at 65 mph it sits you back in seat & throbs. These are ligit dyno numbers at crank. Not “happy dyno numbers” now these engines could drive across the great USA & back several times with zero issues.
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.
 
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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.
 
Today's trivia lesson.

Howard Johanson (Howard's Cam's) was a neat guy that drank beer from quart bottles.
 
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.
 
frnkeore said:
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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Frank,
The lift figures of that Howard cam are very similar to ones used by the DO Hal for mile track events.
 
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?
 

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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 !
 
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.
 
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.
 
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.
 
Ldjr003 said:
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.
Click to expand...

Flat tops give us 14 to 1.
 
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