flathead speed
 

35 coupe, 284 inch 8BA, 3.54 ģears. I had her clocked at 90 with the gps and she was still climbing when I let off. No tach...wonder if it will do 100?
Any of you guys ever wring it out on the hghway?

Re: flathead speed
 

I got my stock '51 club coupe to 85 on the speedometer once about 25 years ago. I think the engine may have had some more; I know the suspension, tires, and I didn't! Maybe 75, 80? (3.55 gears and no OD.)

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The engine will do 100 alright but i don't know about that Avatar. Walt

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In my college and early working days I had a bone stock '50. It was converted to OD so it had a 3.78 rear I guess. It would do 90 (by the speedo) in second gear in OD. It wouldn't do much more in high OD. That 284 should pull strong till it runs out of breath. I would think 100 is in easy reach of it.

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Got my '51 Merc OD 4.27 rear into the 90s (on the speedo) on a NASCAR track. I ran out of courage before the engine ran out of steam.

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Ha, Walt, thatss my dally beater. 265 8BA. I dont believe its ever been over 60...........

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Got my 53 merc fordomatic bone stock in the 90s according to the speedo. Guy trying to catch me was doing 105 in a 2008 z71

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Well done! my heavy old 35 sedan with waterpump in heads 21 stud and 3.78 ratio bum will regularly not go any faster than 79 MPH in second gear. Doesn't blow up either!
I read it on the 'net somewhere; I think it was about Arkos Duntov, about how they realised a flathead runs outta breathing before it gets into dangerous revs, therefore was an ideal platform to 'modify'. So...with this information I regularly put it to the test. Sure enough...they get to a max speed and will not go beyond it. What the absolute toip speed would be, I can't tell you, roads in NZ are not long enough, and I'm too chicken!
One thing I do know, the 284 I built and put into the same test rig 35, did not go as fast as that little 221. That longer stroke just will not rev out the same.

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Breathing is what limits RPM unless you have valve float or weak ignition.

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I was clocked by the state troopers about 12 years ago at 118 in my 51 merc. basically stock , 3sp w/ o/d, 4:27 rear. was almost out of steam. had a couple of guys in it at 105 that did not believe me until they rode in it.

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I agree with Walt. Things get very interesting above 70 in my truck, so I prefer not to push it. The engine will turn over 5000 RPM with no problem, but the rest of the drive train and steering is "cutting edge " 75 year old technology!
Just my 2¢...

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Of course, this was a coordinated effort between you and the State Troopers, yes?:D
Ken

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You, of course, have the framed citation hanging on the wall in a prominent place, don't you?

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So 5000 rpm is about all a flathead can handle?

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What did the cop say about it? Did he at least pay you a compliment on the Merc?

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The stock flathead runs out of breath around 3500 RPM. I think you should check JWL's book "Flathead Facts" He did a series of dyno tests on the engine adding everything you could think of to it except supercharging. He never got over a 100 hp or 3700 with out changing the cam.

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Our Bonneville 49 ford truck , on the salt with 3:50 rear axle will run 4300 when held wide open for three miles !!! We needed 4500 for a record! (its a 265)
A change to a 3:73 rear axle and it will run 4500 but speed drops way down ( like 88 mph).
We have decided we need a bigger air pump, our next trial is a built 304 ci , hopefully at Willmington Ohio next year ! A flathead will only pump so much air !!!!

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I have been there @ 105. So has my son. Fun ride! :) Bill PS. There was still more on tap. It was still pulling!

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JIM, a bigger engine needs more air. The Key here is in the ports, valve and cam. This along with the right intake and exhaust. It's a real problem Ken Kloth went 13?? MPH something with 265ci. Might go faster with a 258, I ran a 258 in a hydro and it went faster than the 284.

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Seth, not exactly coordinated, but it was late at night in the summer ( daylight here ) and it turned out the trooper was one that I knew from work. ( I used to work for the state of Alaska and worked on the trooper cars. ) since it was on a very long straight stretch with no traffic I got off with a very stern warning, only because he could not believe the car was actually going that fast, said if it happened again I would face the consequences. I just made sure I did not get caught again, but never ran it over 105 again, was a little squirrely, even with the radial tires.