Flat head V8
 

Does anybody know what size the flat head V8 is that came in a 1947 Ford coupe? The reason I ask is because my grandpa has a '47 coupe that he changed the frame, motor, and all out of many years back and I have often wondered what kind of performance I could get out of that motor if I chose to rebuild it and put it in a smaller vehicle like for instance... a 1928 Model A. I have been wanting this car for many years now. I know the flat heads can be pretty but how well can they perform and what size is desirable? Also is it expensive to rebuild one of these? Thanks for the info in advance. I read in another thread where GB SISSION said he has all the flat head V8 specs committed to memory so maybe he will throw in his opinion.

it should be a 239 cu in engine of around 100hp. the Mercs from those years used the larger 255 version.

biggest problem with them is that they tended to crack around the bolt holes so finding a non-cracked block is pretty rare. i think i read somewhere where someone is making a new aluminum block but can't remember who.

as far as performance, they are no powerhouses due to limitations of the valve in block arrangement and that they only have 3 exhaust ports (the two centre cylinders share the same port). even built up you are very unlikely to see 250hp without a blower on it.

but that being said they are probably one of the best looking engines out there when built up and blinged out. in my opinion they are the only engine that looks right in a 32 duece coupe hot rod.

lots of aftermarket parts still available (like aluminum heads, intakes, headers, cams, etc) to still build these up and they do have quite a loyal and suprisingly large following still.

I say go for it.

Rgds
Mike

I'd be cheating if I looked anything up. Would be a 59AB engine, yes 239 cu in. 3 3/16 bore. The earlier (pre 39?) would be 221 cu in with a 3 1/16 bore. After years of daily driving/work truck use I ended up with a 239 cu in 59AB witha 4" stroke merc crank and yes, 255 cu in. Other than the merc crank, I like them in stock form. Seeins that Ive never been a go-fast guy I just love the way a stock engine idles. All the dress up and speed equipment are way cool, but with wild cams and such they just don't settle down the way I like 'em. Now that I'm getting older and I have managed to stuff most of my fingers into the tablesaw (cabinetmaker) and my eyes aren't quite as good, I REALLY like the later engines (8BA) with the top mount distributor. The nasty flat one driven off the cam and hidden under the belts is supposed to be better, But I'd convert it to the single point. I've heard it's not too hard. I do however agree with the previous poster that it's never gonna be a real powerhouse or an economical dd. Model A's are pretty light though.......Like he said... go for it!

I think the motor would probably end up looking better than it would perform. I just thought it would be kind of neat to do because as far as I know they are pretty rare. I don't have the Model A yet but I would love to and if I get one I think a flat head V8 would look pretty sweet in the engine compartment of a '28 Model A. But it's not a realistic source for HP right?

imho if you are looking for hp vs cost you should stick to a late model v8. maybe a 289-302-351. if you have a HUGE checkbook, go with a blown flathead. from the way it sounds, your not gonna be happy with the horsepower from a flathead. just my opinion.

There's still nothing else that sounds like a flathead. I have a good friend we call "flatheads forever" He loves them, even has one hooked up to a C4.

I definitely will not be having a huge checkbook. Everything I do could be featured in Hot Rod magazine's article "Build on a Budget". The only difference is that I really don't have the extra money to spend whereas they can spend as much money as they want. I think if I build the flat head it will be with the goal of making it look good and not a goal of making tons of power. From what I gather flat heads are expensive to build and not very powerful.

Besides the distributor being easier to deal with in the 49-53 8BA type, the rod bearings are regular modern shell type bearings. The pre 49 have a 'soup can' rod bearing that has a bearing surface on both sides of it. I have found it's very confusing to modern machine shops run by young whippersnappers. They act like you're the one that doesn't understand rod bearings, and then they proceed to do it wrong. Most machine shops can do the later type. If you have an earlier one, I'd take it to a flathead specialist and that's where the big bucks begin.......

So in other words... If I want to even do a simple rebuild, I will have to shell out the cash. The vehicle it came out of is a '47 Ford Coupe so it will be the more expensive one to rebuild. The only reason I would rebuild it to begin with is to have a nice lookin old timey V8. I think flat heads look great when done right. I wouldn't be very concerned with HP seeing as how I would have to supercharge it to do so.

IMHO, the flathead V8 is very satisfying to own and drive in it's stock form. Putting one in a model A would be cool. That combination is what started the popularity of hotrodding in the USback in the 30's 40's and 50's. It's been done thousands of times so we know it works. If you can swing the $ for the rebuild, it would be a cool thing to own. Maybe not the most practical ride ever, but look at my signature and a few others here, and we can't say much about practical. .....

See that's what I'm thinking. I think that even stock would be fun to drive. A stock rebuild would be all I would do since it will be expensive to just do that. Now I just need to find a '28 Model A Tudor Sedan for a reasonable price. That's my dream car...

Back when I was involved with model As, the tudor was usually the easiest to come by and the least expensive. You will most likely want juice brakes, and that's easy with the A. While I don't keep up to date on this, I've heard that the value of As and Ts is dropping because this generation of collectors (baby boomers) has no childhood connection with them and they go for the muscle cars. Now go look on Craigslist or Ebay.........

Having ridden in a flathead V8 powered 30 Ford roadster many years ago I have to say a flathead is definitely cool, but in it's stock form it barely has more grunt than the original 4 cyl. The cost to build these engines with any noticible horsepower improvement is exorbitant so you have to decide which you want....coolness factor or HP. If HP is more important a more modern engine is the way to go! :-X0A6

That seems logical but I've been on the lookout for a modestly priced stock 31 deluxe roadster and have yet to find anything approaching modest. I don't know if values will drop in the coming years but maybe at least they will not appreciate as fast as the muscle car segment.

I've been looking off and on for one, and a descent Model A, and by that I mean rolling chassis that the body is still mostly intact, is going for around $2000-$8000. But then I'd have to drive to California or Colorado. Which is a long drive for this Tennessee country boy. Too bad I can't find one in perfect condition for $500 across town. That would be too perfect.

And thank you, GreatNorthWoods, for the insight about the lack of power from a flathead V8. If that's the case I may have to rethink. I still don't know yet though.