Wanted: Old School Flatty Knowledge!

I was fortunate enough to come across a pretty solid deal a few moths back, a 51 Ford coupe in excelent condition (Runnning w/ original 8ba). The price was right and the 51 came with a complete 2nd block (8ba, 3 Holly 94 carbs, 2 Stromberg 94's and a offy-dual intake). Yea Jack pot!!! My project for the next year is to build the 2nd engine VERY STRONG...From what I've read I should expect no more than 170 to 200 hp max out of the flatty, and thats fine. (I want to maintain the integrity of the car and that time period) NO F-ING Billet! I would like some imput on an engine set up. i.e crank set up,matching cam, bore, pistons, port polish, relieving etc. I would like to go with a 4-inch stroke or a 4.25 inch stroke...Remember I'm planning on around a year to build and I'm not filth rich either... Buget 4K to 5K for the year! Keep in mind I want this to be a rip roarin' daily driver...
Thanx,

 

Try this site for Flatheads then click on Techno Site link on left hand side.

http://groups.msn.com/FordFlathead1932to1953/general.msnw

 

I also am building a new Flatty. I have a 4 inche Merc crank, stock Merc rods, and a good '51 Merc block. I'm gonna hog it out .060 over, run a big 'ol Isky cam w, adjustable lifters, stainless valves, Baron heads and 4 carb intake with 4 94's. Electronic ignition, generator, mechanical fan, open pipes,.......the good stuff. I don't think I'm gonna releive the block...no need. It will get ported to the max. Anyways...thaat's my plan. Might get 200+ hp out of it. In my 1400 lb roadster, it'll be plenty.

 

look in the tech archives, tons of info.

 

Dont wanna rain on the parade, but most guys wont get 200HP+ out of a souped, nat aspirated flathead on the street PERIOD. Maybe 160-175 tops with mods that have been described if the combo works well.

Now with a blower thats a different issue in itself.

Rat

 

Petes full of **** ! love Pat

 

Ooooooh......you wan summ? Confucious say "Lightweight Roadstuh haul much *** with enuff powah."

 

true, true. but 200 is a lofty goal for a NA flatty, and it IS a 800lb motor and trans... still will get walked by a stock 331 caddy or motor of the same era...

im in the same boat as you though, im gonpna run a stock 303 rocket with 3x2 intake and zoomies, so maybe 160hp, bunch of torque to help me though... basically a ealry rocket is a tiny step up from a flatty.. although i do love tehm, and i wanna build one one day

 

Go to www.fordbarn.com There is tons of knowledge there from guys who build nothing but flatty's. P.S. There are better ways to spend you money
on a flatty instead of going for the 4 1/8 or 4 1/4 stroke. Remember, it's gotta run cool.

 

Yah - the numbers are a tad high.

Part of the problem is there was a book published a few years back by a supposed 'expert' on flattie builds which included some 'dyno' sheets at the back of the book. Please note the 'dyno' sheets were from a PC modeling program called...Desktop Dyno.

While the program is fine for modeling OHV & OHC motors (I've used it with accurate results from time to time) applying it to a flattie yields, umm...optimistic horsepower figures.

That's not to say 200 HP isn't possible outta a flattie - but 200 HP and a daily driver...well...as long as it's only a few days here and there, you might.

Back in the day, some of the hottest flatties around were in the low 200's - and that was on a non-pump fuel blend.

There are a gajillion threads on this subject - and more experts than you can shake a Johnson adjustable tappet at. do the searches, learn the insight..it's all here! just remember that a hottie flattie inna fitty-one shoe will get it's clock cleaned in the quarter by the average modern SUV these days, so...rip roarin' is relative.

Hell, I'm so old I remember when slow was fast...

 

I'm gonna get two-hundy if I hafta spray it (I'm not afraid to break stuff). As for dailey driver status......um, no.

 

Flathead HP is indeed a different beast than OHV power--and at least half the differences are mathematical. The formula that derives HP from measured torque is so structured that numbers are low as long is RPM is below 5250, a level at which even hot flattys are dropping off fast.
There is a fat torque curve, and there are results. By the early fifties actual street roadsters were reaching around 140. They probably would not have shown 200 on a dyno. A kid with an '86 Camaro that reached 140 would probably tell all his friends he had 600HP...

Look at this olde post--fat car, 3500 pounds, stock cam, about to go 15's.

I'd guess 130 HP. At most.

 

A repost:
Here’s a dyno/drag test from about 1954, excerpted from the 1955 HRM annual. Real numbers from these times are scarce, and even E.T.’s were rarely reported. Most drag results were strictly MPH.
Note a few things about these tests: They are modifications on an existing used car, not a full build up. They are entirely bolt-on mods on a stock 239 short block, without even a cam change. The HP numbers are rear-wheel ch***is dyno numbers, NOT flywheel HP. Onward:

The car involved was a stock 1940 Merc club coupe, which would have been a typical back-row-of-the-used-car-lot teenager’s car in 1954. The engine was a commercial rebuild, described as “in neither excellent nor in poor shape” with 12,000 miles since rebuild. The pictures show it to have a Stromberg and a dime store chrome aircleaner, probably giving a slight power loss from stock.

Stock with distributor freshly strobed and new plugs (H 10), it pulled 69 HP at 50 MPH on the rollers and turned a blazing 17.23 @65.47 MPH at the Santa Ana dragstrip.

Test 2 added a Sharp super dual with two 97's, stock except for .048 jets (I would think a bit rich?). This produced a 16.56 @ 71.01 MPH, power peak moved to 80 at 55MPH. (Power was tested at speeds from 30 to 60 in high, with practically all mods showing improvement at all tested power levels, by the way).

Test 3 was with the addition of 8.5 to 1 rated finned heads; They carefully avoid stating or showing brands, I would guess because they had so many advertisers to offend. They were R type heads requiring changing out the shorter studs. This produced 84 HP at the wheels at 55, and went16.07 @74.99 at Santa Ana.
Test 4 added dual exhausts and a pair of Hollywood Deeptone mufflers, used with stock manifolds. 86HP, 16 flat @ 75.01.

Test 6 added a Harmon-Collins dual coil, which produced only trivial gains over the fresh stock distributor.

And that was it for that issue–only modifications that an ignorant teenager with $5.00 worth of tools could have performed in dad’s driveway on Saturday. I really wish they had gone on to a cam and headers, but no such luck. Bruce.

P.S. Guesstimate those numbers into flywheel numbers, guess the weight (probably about 3300), and run them in standard formulas.
Results, while purely guesstimates, are interesting.

 

Check these two websites. Tons if info about rebuilding a flathead. They don't really focus on squeezing extra ponies but it's still good info.

http://www.vanpeltsales.com/FH_web/FH_37-48engine-rebuilding/v8_overhaul-forwrd-contents.htm

http://www.flatheadv8.org/rumblest/intro.htm

 

Then, compare those numbers with this from a thread on '55 chevy power packperformance: Notice the improvement on a car of similar weight with a second generation OHV, doubtless producing much more than 86 rear whell HP.

"a book I have shows that several magazines ran 1/4 mile times in the low 17s with a power pack 55, with 3 speed trans. "

 

when i went to work on my T, my goal was to get 50hp out of it...anyone got a dyno in the Bay Area where i can run the T on it and see what she'll do...

 

I could see the rollers just swallowing a "T", leaving a flat piece of sheetmetal down in the pit...better chain it to something heavy...
Don't ch***is dynos have problems with cars with near-weightlss rears?

 

If you're referring to Joe Abbin's book, he's recently backed it up with dyno runs of 200+hp N/A & 300+hp blown. If you're referring to one of the other books...I can't recall which it might be.

IMO, the problem with flatheads is so much is half-truth, BS, & outright lies from back in the day - most results were by trial & error, not scientific approach (dyno & flowbench) - that doesn't invalidate anything done back in the day, it just means quantifiable data is hard to come by. Add to this the secrecy surrounding most racers & their cars in order to gain/retain their edge, & I'm all for the white coat, pocket protector crowd running repeatable tests with modern equipment to obtain quantifiable numbers.

Flattys need help breathing, that's one of the reasons they respond so well to blowers. If it were me building an engine for a shoebox, I'd be sorely tempted to stick with something like a 276 & a blower - nothing tooooo exotic...

...and you'll still get your clock cleaned by a mild SBC!

 

"...and you'll still get your clock cleaned by a mild SBC!"

Like that fierce power pack...

 

Nope - not abbin's book; I'll hafta look it up when I get home. Agree with everything else you said - even now, with the advent of calibrated ch***is dynos everywhere, there are guys touting big-*** nunmbers for their 'project' motors - which make 30% less than claimed on the dyno.

Part of the problem is the manufacturers have consistently LIED about HP/TQ - even when we went to SAE net ratings for motors, the average unit produced a good 15% less than advertised. If you're running a **** dyno on the street and have a head-to-head run with an optimistically rated motor - you'd think you had more HP on tap than you had.

 

I have faith in my ability to destroy Flathead parts.....stay tuned.

 

Go back and re read Bruce Lancaster's posts. Remember: Dynomometers don't measure horsepower-they measure torque (at some R.P.M.); mathematics converts the torque (at some R.P.M.) to horsepower. Due to the nature of this mathematical relationship, horsepower cannot exceed torque until the engine gets to (or past) 5250 R.P.M. It's a rare flathhead that hits or exceeds that number and even then it would have to be producing 200 # ft at that R.P.M. It takes a blower or nitro or spray to get into that range. Most N.A. flatheads start to go downhill on torque after 2500 R.P.M. All these "late model" ch***is dynos are of the "inertia" variety and they may read H.P. directly but that's because they've performed all the math mumbo-jumbo internally before you see the read out.






quote=4-Chaos]I was fortunate enough to come across a pretty solid deal a few moths back, a 51 Ford coupe in excelent condition (Runnning w/ original 8ba). The price was right and the 51 came with a complete 2nd block (8ba, 3 Holly 94 carbs, 2 Stromberg 94's and a offy-dual intake). Yea Jack pot!!! My project for the next year is to build the 2nd engine VERY STRONG...From what I've read I should expect no more than 170 to 200 hp max out of the flatty, and thats fine. (I want to maintain the integrity of the car and that time period) NO F-ING Billet! I would like some imput on an engine set up. i.e crank set up,matching cam, bore, pistons, port polish, relieving etc. I would like to go with a 4-inch stroke or a 4.25 inch stroke...Remember I'm planning on around a year to build and I'm not filth rich either... Buget 4K to 5K for the year! Keep in mind I want this to be a rip roarin' daily driver...
Thanx,[/quote]

 

Hey Pete . . . gotta love your at***ude and desire for more Flathead horsepower!

There are some good posts that cover the NA flathead subject pretty well. With the limited cubes you have -- probably no way to get close to 200 HP. In order to have any chance at 200+, you'd need as many cubes as you can get, probably large valves, probably a relief, a big *** cam and you'd be flogging it pretty hard. I'd love to see it . . . just a tough goal to reach without being a strictly race motor -- with no bottom end to speak of. If you run it on an engine dyno - let us all know . . . real numbers would be great. When I complete my next blown flathead - I'm going to do some dyno work -- should be fun. (not for 6 - 9 months -- am in the middle of an expensive *** early hemi at the moment).

For real flathead HP . . . put a blower on it's head and stuff it full of air and fuel!