Boring a flathead

[Ol' Ron]

Boring a Flathead depends on your age. 55 and under .060, fore 55 .125, over 7o .182. and if your like Rumble seat, who is older than dirt. .250. And it still runs cool, nice torque motor .

[NealinCA]

I bored mine .040 at 40.

[Pete]

Originally Posted by Ol' Ron

Boring a Flathead depends on your age. 55 and under .060, fore 55 .125, over 7o .182. and if your like Rumble seat, who is older than dirt. .250. And it still runs cool, nice torque motor .

How about if you are older than Rumbleseat?? I'm older than salt and you know what the Spartans did with salt.
.250 is a practical first bore for a flathead.
It leaves room for one cleanup...The rest of the engine is usually shot
after that.
I pity all the people that build street flatheads these days..They will never experience the back slapping acceleration and the screech of air going down 4 48's at full throttle...They will never experience the rump rump idle of a 280 degree cam as you idle down the street at 30 mph.
They will never experience the sound of the engine turning 6000 as you bang the next gear...
I always wonder if there are any TRUE enthusiasts left out there like we were in the 50's when almost everyone drove their hot rods to work every day and had at least one stoplight race a day.
We drove to the drags every weekend and raced. No trailers or tow bars.
I guess I am preaching to an audience of one though.

[craneygartz]

I took this 8BA to 3 3/8 at 17 years of age in 1957. Why? The block came with free pistons that size!

John Oder

[Walt Dupont--Me.]

I built a 3-3/8x4-1/8 =296 when I was 17 that was 57yr's ago. 3 duces, almquest cam. In a 39 coupe. Use to drag race in Sanford Me. Walt

[PeterC]

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[QUOTE=experience the back slapping acceleration and the screech of air going down 4 48's at full throttle...They will never experience the rump rump idle of a 280 degree cam as you idle down the street at 30 mph.
They will never experience the sound of the engine turning 6000 as you bang the next gear...
I always wonder if there are any TRUE enthusiasts left out there like we were in the 50's when almost everyone drove their hot rods to work every day and had at least one stoplight race a day.
We drove to the drags every weekend and raced. No trailers or tow bars.
I guess I am preaching to an audience of one though.[/QUOTE]

I'd like to think I drive my flatheads "enthusiastically" but with extreme horsepower I am respectful of my 39 trans and Columbia as the weak link! - based on your "back in the day" description - just curious how often you blew things up when you pushed like that!

[Pete]

Originally Posted by PeterC

I'd like to think I drive my flateheads "enthusiasticlly" but with extreme horsepower I am respectful of my 39 trans and Columbia as the weak link! - based on your "back in the day" description - just curious how often you blew things up when you pushed like that!

Not too often..I was well aware of the weakness of 25 tooth gears although they did last longer than the other sets because of less torque multiplication..At the drags I started in second so there was only one easy shift...I road raced with the 25's also and used 1st gear in the slow corners...Early racing antique sports cars developed my skill at double clutching crash box transmissions. (a la 1st gear in a 39 box)
As far as BS, I don't deal in BS...If I post it in public, you damn well better believe I have documentation to back it up.
Oh, one other thing, the timing slips I have were read off the Crocker clocks, the same ones they used at Bonneville in those days.
They used to bring them up for the 4th of July 2 day race every year.

Oh, and YES, 6000 rpm shift point....They would pull to 6200.
With nitro, 6500.

[Ol' Ron]

Pete, My first flathead was 3 3/8 X 3 3/4. bought the pistons from Von Eslers Speed shop in Chicago. Had the block bored in Ft Athinson Wi in 1950 by the Ford garage in town. When thwy saw the size of the pistons they refused to bore the block unless I paid in advance. 5 bucks a hole. I bought a used cam and lifters at the same time, don't remember which one. That was a while back. Two duces and milled stock heads. I'd like to build another.

[Pete]

Originally Posted by Ol' Ron

Pete, My first flathead was 3 3/8 X 3 3/4. bought the pistons from Von Eslers Speed shop in Chicago. Had the block bored in Ft Athinson Wi in 1950 by the Ford garage in town. When thwy saw the size of the pistons they refused to bore the block unless I paid in advance. 5 bucks a hole. I bought a used cam and lifters at the same time, don't remember which one. That was a while back. Two duces and milled stock heads. I'd like to build another.

I wish you had been around out here..I would have let you try out my 32 coupe....(Everyone else did)
If I took everything off it that would come, it weighed 2300 lb.
Turned 120 in 11.34.....That would have put a smile on your face.
That was a 315 ci, 4 carbs, H&C mag and 404 cam on 145 av gas.
Drove it to work every day.

[JWL]

Here we see examples of "the older I get the better I was" syndrone. Such BS is ok so long as you make unknowing viewers aware that there are few facts available within.

[Straightpipes]

Originally Posted by JWL

Here we see examples of "the older I get the better I was" syndrone. Such BS is ok so long as you make unknowing viewers aware that there are few facts available within.

Viewers be aware, You are in company of the best, was, is, will be.........
Ol Ron pointed me toward the smiley cam and I'm still smilin'

[Al K.]

It is nice to see the face of the person writing. Gives it that personal feeling. Al K.

[ford1]

Hey Pete, been there, a flat head block was meant to be bored as far as you could, .187, no need to bore to anything else if you were going to street rod it, run mine 3/8 with a merc crank, 4:55 gears, 400 jr cam, solid lifters, adjustables were junk even back then, 2 afb jugs, noting could out run me for the first 100 yards, not even the olds rocket 88's, i could buy flatheads at the wrecking yard for $15 apiece, i still have one engine ready to build with all the pieces stored in my garage, maybe my grand son will like it, my sons all use the chevy v/8's, where did i go wrong?

[Ol' Ron]

This isn't BS, it's embellishment.

[Mick/mo]

6000 rpm. ?

[Dee]

Here's a Lincoln V12 that's been bored to 3-1/16, not much room left. This engine is being installed with a 4 barrel carb set up. Seems the '42 blocks are the only ones cored large enough to do this. This ought to add some "gitty-up" to my '48 club coupe.

[Mike B]

Originally Posted by Dee

Here's a Lincoln V12 that's been bored to 3-1/16, not much room left. This engine is being installed with a 4 barrel carb set up. Seems the '42 blocks are the only ones cored large enough to do this. This ought to add some "gitty-up" to my '48 club coupe.

My kitchen table isn't that clean!

[Henry Floored]

This thread is fascinating to me. In my opinion the "Holy Grail" of Flathead performance is to get the edge of the cyl as close to the edge of the intake port. Then using a pop- up piston to give the air charge a large chamber to flow into. So far that's my theory but I plan to put it in motion very soon. I would like to get the largest practical cyl bore dia with the largest intake valve I can get in there, and I'm gonna use pop-ups on the street in my coupe. Don't see why not.

Would love to know how you fellas are getting such large cubes. What bore and cyl wall thickness are you ending up with?

I want to emulate this situation in a Ford Flathead....

[Henry Floored]

Now I'm not talking about actually moving the valves. Rather changing the relationship of the intake port to the combustion chamber. The only practical way I can see is by going to a pop- up affair.

[Pete]

"Would love to know how you fellas are getting such large cubes. What bore and cyl wall thickness are you ending up with?"

Bore = 3.405
Stroke = 4.750
Wall thickness = average .090