hey guy's,

i'm looking to buy a project '51.
it has the original flathead 6. (4.2 liters is this possible?)

is the 6 a dependable engine?

i'm thinkin to swap it for a v8 flathead
i want to do a rat rod.

like to know if the 6 is strong enough or if you can tune it to make it faster.
it has the manual gearbox
thank you
twan

 

4.2 is possible if its the 254 used in the larger trucks. Check the block or head for pn using 8MTH as a prefix. If it's the smaller 226 (3.75ci) the pn's will prefix with 7HA.

6's are very dependable, smoother running than 4's or 8 due to the longer crank. Bore size for the 254 is 3.5" and stroke is 4.4" so they're natural torque engines - they are not high rpm engines. The engines are strong, but tuning won't make it much 'faster'. There is not much speed equipment that has ever been made for these engines.

Like modern drivelines, you can overcome the speed limitations with taller gears in the differential (a 9" rear from any 57-72 F100 will bolt right in) and use a modern OD transmission like the S-10 T5.

I think they are great in hotrods just because they are unique. 'Course the flathead V8 is sweet also. Your choice - have fun!

 

It depends on what you like. I've heard that 6 referred to as Henry's best kept secret.

A friend of mine had a bachelor Norwegian uncle in northern Minnesota who always drove Ford sixes, because he had to purchase two fewer sparkplugs for a tune-up. Now, that's frugal.

If that is a good running 6, I'd stick with it.

 

I heard when Ford first came out with the flathead six it was more powerful than his flathead V8 and so they had to de tune it a bit. But for raw get out and go, the v8 probably will do better as it can be run to higher rpms and will have more speed equipment available. Still, if it were me I'd take the six.

 

I am rebuilding a flathead 6 226. I bought the deluxe rebuild kit from kanter. I was told by Story motors, who rebuilds flathead, that he has had to junk fewer 226 or 254 due to cracked blocks. After I tore apart two flathead 8's and both had numerous cracks, I finally agreed. I tore down the 226 and block was good. I ordered kit and engine will be bored .030 over by next week. Story is going to let me assemble it right in his shop. He doesn't want me to screw it up. Nice to be in small town. This is just what I'm doing, an original as possible rebuild of a 51 F6. Next I will start a 51 cabover.

Good luck with your project.
Kevin

 

My 51F1 had has the 226, it had been sitting for 17 years prior to my purchase the 226 was not froze up when I purchased it. The PO had started converting it to 12V and gave up 1/2 way through. The engine had no compression due to the valves being stuck open, I poured in Marvel Mistery Oil and left it sit for a week. I then added more, after the second week I was able to get it started. I really ran rough but I managed to drive the truck 28 miles home. That was 3 years ago and the 226 is still running good for not having been apart sense 1971. The only problem I see with them is if you plan to venture out on any long trips and you have a breakdown you could be sitting for awhile trying to find parts. Especially if you loose the gear that turns the distributor/oil pump off the cam, they can be real tough to find. The early 7HA and the later OHA model are both different, also the cams are different (from what I understand). There was a guy in Europe here awhile back trying to track one down, he did finally find one. The V8 Flathead is the one I tend to lean more toward because of the availability of parts is so much better. But if you really want whichever Flathead you choose to rock put an S-10 5 speed trans behind it, it's a perfect match. JMO

 

I have to dissagree about the six being a smoother running engine than the eight. I cannot imagine it running smoother than my V8. As smooth maybe but smoother I just don't know. My truck runs smoother than anything else I have driven, including anything new.