HOW Many HP's can you realistically get out of a Flattie

What have you guys been able to get or seen pulled out of a flathead for horsepower?. I'm going to drive it like a sum of a bitch and want to be able to roast em every once in a while. Matt

The smarter, funnier, and better looking Strube Brother!

 

I saw one with a blower putting out like 350 HP. In a small car (Model A) it should be good for a 12-13 second 1/4 mile. I don't know a ton about flatties though so I don't know what they put out, but it isn't going to be earth shaking....

Cool but not real big numbers. Not that the numbers make a bit of difference at the drive-in....lol.

 

I was watching one of those shit shows on speedvision(shop with the checkered floor) & they took a 49-54 flattie, put in alumn rods & pistons, SS valves,a cradle that supported the crank, a forged crank,alumn finned heads, a pointless distributor,a blower, 4BBL on top of that & a bunch of other shit i can't remember, (but it was very expensive), put it on a dyno & got 278HP!!!
that sucks, ain't worth the hassle!!
JimV
PS but nothin looks better then a flattie with 3 dueces on it!!

 

Did you see that Hot Rod article a few years back about the "Apocalyptic Flathead"? It was something like 550 HP, but it was alot of high dollar shit too. Really cool engine, though! They swapped the intake and exhaust ports, added a Centifigual blower, Chevy con rods, billet crank... it was actually pretty cool...

Jay

 

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I'm going to drive it like a sum of a bitch and want to be able to roast em every once in a while. Matt

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im guessing the your gonna have 3 strong disagreements with that statement!!!!!!!

39 box-

axle keys-

axles-

 

It's not about horsepower... it's about torque.

A warmed over flathead isn't going to perform like a warmed over small block Chevy.

But you're not building it in the search for speed... will it move your little 2000lb hot rod around? Yea, and it'll wax the snot out of most Hondas on the road... but is it going to run 12, 13... or even 14 second quarter mile times?

Probably not.

Besides, if you want to beat on something and record quarter mile times... I wouldnt' suggest building an av8 roadster...

The reasons for building an av8 roadster are because you like the Nostalgia of the car... appreciate the history and want to feel what it was like to drive a hot rod 55 years ago.

My advice would be to at least get your chassis up and running... at this point, you're into it for peanuts... I'd take Steve Hendrickson up on his offer to take you tin hunting back there... and have fun.

When you're done, if you don't like it... I'll trade you the Roach Rod for it... just make sure to put a rumble seat in it for your nephews.

Sam.

 

In my humble opinion, if you're going to build a motor that is going to kick everybody's ass you're going to sink a lot of money into any motor but, if you want to look and be cool a flattie is the way to go. Just about any overhead valve will beat you in the quarter mile but, you can suck the doors off of any thing on the street with a well done flattie.
Roy Creel has a Banger (32-24 Ford four cylinder) that does 216 MPH on the lakes but it is heavily modified.
I like the old ways. That's just my opinion, I could be wrong.
Speed costs money. How fast do you want to go.
No guts, no air medals.

 

Figure 125 to 175 hp for a reliable street motor. Some guys are claiming 200+ hp w/o a blower and on pump gas......bench racers that should be wearing rubber boots! The little Ford flathead is cool looking and sounds great. However, you are never going to take on modern OHV motors with an antique little L head unless they a very sickly (smog motors) and their drivers have senior center reaction times. You might be able to choose off a kid on a 10 speed, but stay away from LT1s, Mustage GTs & Rice burners!

 

You're on target about torque, Sam, but let's not be too quick to give the Henry motors that patronizing pat on their flat heads.

Jim "Jazzy" Nelson's Fiat-bodied AV8 -- probably about as light as the BFD -- ran 9s in the late '50s and was the dominant top-eliminator at San Fernando, week after week. Jazzy's 1956 9.10 record at SFDS is considered questionable by some, but San Fernando had a solid reputation for not squeezing the lights, unlike some other strips. The previous ET record, set in 1955, also at SFDS, was 9.44 by Lloyd Scott in the "Bustle Bomb," with a Cadillac V8 in the rear and an Oldsmobile V8 up front. Gotta wonder what Jazzy could have done with modern slicks . . .

Fast forward to the early '60s and consider Ed Bingelli's F/Gas Willys coupe that not only dominated its class in NorCal drag racing, but humbled E, D, C, B, and even an A/Gasser or three in end-of-the-day "king-of-the-hill" competition for all Gas class-winners at HMB, Fremont, Kingdon -- low and mid 12s with 286 inches of carbureted flathead. All done at 2200-plus pounds wet.

What tends to get forgotten is that these low-hp flatheads are decidedly undersquare -- a great configuration for developing bags of torque right away.

 

"Jazzy" and the flathead-powered Fiat. Please pardion the moire of the screened picture.

 

I thought TATTOOS and FAT chicks in 50's skirts MADE you CAR FASTER???

 

Duh Germ, Fat chicks give better head, making you push REAL hard on the gas.....

 

I know Mike.

Tony Nancy had one hell of a good running, 10 second roadster, with a flathead in it.

But Smalls has ridden in almost every car I've built in the last 15 years... and each one of them ran 12's in street trim. I think the Roach Rod is the only exception... but 13 oh's @ 106 with a 4 speed and 5.5" wide tires makes that 13 flat seem like 11 flat.

Anyway, I think he should build what he set out to build... the satisfaction alone in seeing all that Ford stuff assembled into a running car is enough to make it more than worth while. The other day when I unloaded his freshly hot tanked Merc motor... I just looked at the nice casting, the block and its simplicity... and just smiled.
Sam.

 

Of course those SBCs were thirty- and forty-over 283s, right, Sam?

Is Smalls going to port his block? If so, I'd be happy to do one cylinder for him to use as a guide for doing the rest. Nothing radical, just a good street porting/port-matching job.

 

Several random thoughts:
First, someone PLEASE drag out the circa 1955 R&C with the "world's most powerful flathead" story--I think that one, a blown fueler, was dynoed at about 500, and I think it was the motor that blew through the mythical 140-something in the quarter barrier that Huntington had computed...I can't find my copy, I think it's in two issues.
Next, ignore a lot of recent bookage and magazine articles with big numbers--they seem to be from computer simulations running optimistic breathing factors and such.
Third, don't be excessively alarmed by the LOW numbers you see--you get more bang than you would expect from the numbers, I think because, as AV8 says, the curve is low but it is very fat.
Think light car--you have too little displacement to get much in a big car. Remember, all the common points of comparison out on the street have 100 cubes on you. The OHV revolution was fueled as much by displacement as by efficiency--engines suddenly went up greatly in displacement in 1949!
I'm going to repost here an ancient test I've posted before with some of the very few real numbers from the fifties. Note that this test is with stock cam (a very serious cork) in a heavy car--estimate what moving this cheap little engine into a deuce and losing 1,000 pounds would do!
Also, I will soon post a matching test on a '49 Olds, which will surprise you...

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 chassis 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.

 

Some more comments...

Bruce is a genuine flathead god in my book. I read his comments all of the time, and man I am always learning. Thanks Bruce.

I had one of my flathead engine blocks machined at Motor City when Kirby was still doing machine work. Although I was interested in a fast motor, my engine isn't scary fast compared to many. 286 ported, relieved, polished, big cam progressive 4- 97's Roto-Faze dist, Baron heads, blah blah blah, you know the drill. They machined everything there, but I bought all of the parts and assembled everything. Kirby claimed the set up was good for just under 200hp.


The big dollar Ardun motors and the blown mills he set up for his celebrety clients, he said were in the 220 range. Other than Bonneville motors in cars like Flatfire, I haven't seen or heard of many flatmotors in any car having more than that, and are really drivien anywhere. BUT! I never saw one running on a dyno, or saw a sheet from one run on a dyno. All based on what I was told. So of course I am skeptical.

These engines aren't for bragging about HP. I have to say I really like these engines and will always use one if I can. Expensive yes. Reliable... if built properly and with realistic expectations, absolutely yes. Lots and lots of power to beat a Viper or Porsche, no. Not in the same league. Never will be. But in my opinion, they are strong, and as cool or better than most engines. Easy to understand/comprehend, work on, service, adjust, and modify. Don't build a flathead if you aren't willing to compromise on it's limitations. You are likely to be disappointed.

I would love to drag race my roadster to see how it would do in the 1/4 mile... Also love to put it on a dyno and see just what it would pull. If I ever have the spare money, that would really be cool to do...

I still think most street flatmotors out there are in the 150-175 hp range no matter what configuration. ('cept the blown ones). They are just a more conservative engine. There is really no way to efectivly run a 671 blower and 8 carbs on one for a hp increase! Hey! ...Now that would look wild... I should copyright that...

Bill

 

Although 200HP isn't a lot to some, in a little T that Fucking Rocks.

I don't know much about flatheads yet and the biggest thing that has always kept me away from them is power. I've alwasy been intrested in hearing what kinda of real world, naturally aspirated power was possible out of them, without blowing out the bottom end.

Some great posts here.

 

Many flathead performance numbers seem pretty wild when compared to actual engine power. How fast were semi-streetable flathead highboys going at the lakes by the early fifties? AV8 can probably answer that one pretty well, but it's gonna be a pretty big number for an engine that was likely under 200 HP. A Camaro owner would probably start talking about 500 HP if he got up to 130.

 

Bruce -- Do you have any sources for flathead torque figures?

 

Bruce, I'm with you on what some of those cars did back then. Unbelieveable. I have a 5.9 R/T Dakota, and my little roadster with it's relatively low hp motor pulls that car so fast so quickly I am dissapointed to drive the pig motor in my Dodge! I can't believe 50 plus years ago there were guys taking cars and engines like that and running flat out to see what they'd do. It really is astonishing and unbelieveable to me. That's why I wanted a car/engine combo like it. You are right the Camaro guys prbably would claim 500hp if they clocked 130mph... It is a fact you don't need that much, not even 1/2 that hp to go that fast... Khougaz roadster 1949 Dry Lakes 141.95 mph witha a four carb edlebrock headed 296ci naturally aspirated flathead... maybe 200 hp. probably less... unbelievable...

 

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I'm going to drive it like a sum of a bitch and want to be able to roast em every once in a while.

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I would look at your tire/gear ratio combo!!

 

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What have you guys been able to get or seen pulled out of a flathead for horsepower?. I'm going to drive it like a sum of a bitch and want to be able to roast em every once in a while. Matt

The smarter, funnier, and better looking Strube Brother!

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Speed costs money how fast do ya wanna go?

 

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Bruce is a genuine flathead god in my book.

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Amen.

One of the biggest reasons that flatheads don't put out big horsepower numbers is because they are limited in the RPMs they can run.

Horsepower= Torque times RPM divided by 5252.

How high can you get the RPM variable in that equation? Much higher in overhead valve engines, and even higher in overhead cam engines.

Here's a great link to Horsepower vs. Torque, by the way.
http://www.zhome.com/ZCMnL/tech/torqueHP.htm

--Matt

 

I have played around with a lot of low dollar flatheads trying to make some power without spending a ton of money, I will say once you keep revving the piss out of them the center main cap doesn't stay very happy, there is a couple different sets of main caps you can get but then your talking line boring and total dissassembly, one motor I had fun with is a stock 4" motor .30 over pistons and a weird cam I have no idea what it is, adjustable lifters of course but here's where I found the biggest gains, carb jetting and spacing the carbs above the manifold, I tryed drilling about 15 different jets and did plug chops till i got it right, it's no rocket ship but it does pull pretty good for a flatmotor, for the main caps if you decide to go that far you can check out http://www.wilcap.com/webdoc6.htm

"Muthaheads"

 

Here's the only stuff I have at hand, since I'm at work. This is from a 1944 dated dyno test by Ford, prewar Merc stocker.
rpm torque HP
500 152 15
1000 171 33
1500 180 50
2000 182 70
2500 178 84
3000 168 96
3500 153 102
4000 138 103
That's all they wrote...

Note that most of the engine's torque is available throughout its range. Horsepower is diddlysquat because it is a derived factor based on multiplication, and at low RPM you are multiplying small factors.
Note that this is a FAT torque curve, hence flathead acceleration is MUCH better than the HP numbers show--the formula for HP doesn't start to get exciting until after 5250, right where even hot flattys should be looking for the next gear.

 

I'm not sure how many horsepower I'm making, but with the new 4-71 blower I put on top of my flathead I'm going 14.00 in my full fendered all steel '34. That was my first run with the setup so I obviously have a LOT of tuning to do. The run was made with 4-5psi of boost, but I've got pullies that'll bring it up as high as the motor will take.

All my pictures of the motor aren't online yet, but here's one taken while I was still putting things together:
http://members.lycos.co.uk/zackbass/IMG_0134.JPG

 

Wow, you really screwed up your 14 second campaign by skipping that entire bracket!
I have a whole box gathered up of old and new supercharger books to drag up to Denville.
This should be a good summer for you! What is your current target time for the tuning campaign?

 

I have heard this flathead run without the blower, it sounds like he has a worked out overhead hidden inside that flatmotor.


"Muthaheads"

 

I can tell you that my sons highboy 32 will will blow your doors off from 0 to 60. With the work we've done to the engine I'd rate it at 165 HP. Like everone has said it's not the HP with a flathead and a good engine will surprise you.--TV

 

Thanks everyone for the info. Sorry I haven't responded sooner, but I work nights and sleep days...The only reason I asked about HP's was to find out how quick my little AV8 has the potential for, while still keeping it "drivable" for long trips and such.