Thread: Flathead Newbee Needing Direction!

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Other folks will have other comments but I am at home for the afternoon. I too wanted a "built" flathead but ran into many problems. I bought four blocks only to find all of them cracked beyond use. That said, the question is what can you find? Surely avoid the early 21 stud V8 flathead since the early ones had poured-babbit main bearings. I think the insert bearings came in with the 1938 24-stud blocks. Ignore the tiny 60 HP V8 unless you want to have an interesting Model-T or an inboard motor boat. The early 24-stud V8 had a stock bore of 3 1/16" x 3 3/4" stroke and was the "59A" block which occurs as raised letters on the large bell housing. The early Mercury engines and the '46-'48 Ford "59AB" blocks were 3 3/16" bore x 3 3/4" stroke (nominal 239 cu. in.). The '49-'53 Ford blocks were still 3 3/16" bore x 3 3/4" stroke but the blocks had a bolt-on stamped metal bell housing which was shared by some of the pickup truck models. The best set up was the '49-'53 Mercury block with the longer (torque monster) 4" stroke cranks. I still have a good one in my shed if you cannot find one and they are available from Speedway for about $900; I'll let you have a good one for $500 plus shipping. The real problem is that it is hard to find a block that is not cracked. If you do find one bore it the minimum because those blocks often had core shifts that lead to thin walls after boring. The problem is that rebuilders and rodders have bored out the blocks to 3 5/16" or 3 3/8" and then heating has led to cracks. Note that there are only three exhaust outlets on each side of the block so the center of the block tends to get hotter than the ends and another common crack area is from the edge of a cylinder to a valve and that is essentially impossible to patch. Yes there are still a few "French Army" blocks available in new condition but they cost $thousands not to mention shipping. Then if you do find a good block the cost of a build up will be much higher than for a SBC 350. Aluminum finned heads are $450/pair or more, stromberg carbs are hard to find and expensive to fix and then there is the $900 stroker crank. Hey it breaks my heart to say it, but be glad you have a 350 SBC! It would be cheaper to build a replacement 383 than to build up a flathead Ford V8 these days. Yes there are still a few specialty shops around which can still find the parts and build up a flathead but I'll bet you can build three or four stout 350/383 sbc engines for the same cost, so what is your budget like? Yes you can do it if you have the money. I would use a 4" Merc crank in a 59AB block with the minimum cleanup bore, maybe 3 5/16" but definitely NOT 3 3/8". I'd use an ISKY Jr. cam with Johnson adjustable lifters and whatever two pot manifold you can find along with the visually necessary finned aluminum heads (Offenhauser or Edelbrock). You need a high volume oil pump because the stock blocks were notoriously anemic for oil pressure, a Mallory dual-point ignition AND then add a lightened (chopped or aluminum) flywheel. That would give you a good 3/4 race engine. If you want more you should "relieve" the block face from the valves to the bore and grind out the intake ports to try to make them "straighter" without holing through the sides. Fenton cast iron headers are still available although steel tube headers are cheaper. After all of that you may get 250 HP which is VERY good for a flathead and unheard of in the fifty's but then you can get 270 HP or more from a SBC 350 with a rebuild, a street cam and headers. There is also a good chance that with a bored block and increased displacement your V8 will run hot so you should plan for extra cooling. Good Luck!

Don Shillady
Retired Scientist/teen rodder