I've never had a running Ford V8 flathead, had one in pieces once that was stout in its day, but couldn't keep it. I've always loved these engines and thought them good for about 220 -240 horsepower. I just saw a dyno run on YouTube where a supercharged 59A put out 300 hp, 322 pound feet at 5300. What have you guys seen for horsepower on a flathead that could hold together?
Flathead powered anything are rarer than hen’s teeth out where I live. Even down at the Syracuse nationals the year before last, I think I saw maybe a dozen flathead powered vehicles. I’m thinking most are below 200 hp if naturally aspirated. I just watched the PowerNation YT again a few days back where assembled and dynoed a flathead and thought the numbers they got on the dyno were impressive - 160 hp.
When I was in my teens I drove a few flathead powered Fords. They were fast, fast, fast and had gobs of power. Fast forward 40 years and I bought a nice 47 Ford Coupe with a stock flathead. It ran perfect, but all the power I remembered from my teens just wasn't there (pretty sure it wasn't there in my teens either). A slow corner around town called for a downshift to second. It would accelerate to 60 fairly fast, but acceleration topped off quickly. I did get it up to 85 one time; it might have gotten to 90, but that was about it. In high school a buddy had a nice 47 with a flathead 6. It was pretty torquey, but he wanted more power. We swapped a 53 Mercury engine in the old car. The end result was you couldn't tell a lot of difference between the 6 and the V8. I think he ended up with a Y block in the car. Another buddy had a 39 coupe with a "full house" flathead. Edmunds finned aluminum heads, Edmunds intake with two chrome 97's. Another car I thought was ungodly fast when I was 14. He swapped the flathead for a 322 nailhead. I only rode in it one time with the nailhead, but the difference was amazing.
Naturally aspirated most will be, at best, in the 150-200 hp range. They don't make big power. Unless you spend even bigger money. Flatty's are adequate. Think about it. If you run a stock 100hp flathead around using all 4000-ish rpm regularly you are using the same revs of a modern 4 cylinder which is also making maybe 100 HP in that same rpm range. But the flathead will make more torque in that range than a 4 cylinder.
For some interesting reading on this subject, I would suggest a book named "Flathead Facts" by John W. Lawson. He started with a bone stock 8BA and added modifications and documented each step on the dyno. His results are quite eye-opening.
Mine made 136 hp at the wheels...that was in 2004. Ran pretty well in a 1500lb T-Bucket with a 5 speed and 3.78 gears.
Flathead Facts is a great book that cuts to the facts on modifying a flathead. If you’ve got a stripped down model a or 32-34 and it’s a healthy engine your gonna get a good seat of the pants feel from the torque. Or you can strap a blower to it and get a little more. Both are fun.
Just watched a dyno video of a blown flathead that made 300 hp at the flywheel. It had a lot of modification to get that much HP.
Because of the inherent restrictions of the "L"-head design, flatheads respond to supercharging better than overheads.
Using a GMC 471 blower a flathead can easily make 300 HP and be extremely reliable. I'm talking cross country and back at highway speeds all day long reliable if built correctly. A normally aspirated flathead will make up to 180 HP with what's considered typical mods that being porting and relived block along with at least 1/8 overbore. Attention to cam timing helps greatly as well as any stroke from 4 inch on up. The Red line for each build 5500 RPM. Since you asked about holding together as I wrote above if built correctly with good parts then 6500 RPM is also doable. Our hand built competition stock block 292 CI Ford flatheads burning gas that we run at Bonneville currently hold numerous records with speeds well over 200 MPH. Ronnieroadster
On an engine dyno, I made north of 320 on my 8BA. I could think it could have squeezed out a few more but I was close to squeezing out a massive turd watching the machine shop flog my expensive flathead (I need to never attend the dyno sessions). 471 W/8 psi boost, .125 overbore, 8.5 CR, MSD BTM6, massive amounts of porting, CNC mains...dyne pulls and break in were done with a 4bbl Holley the shop uses for such occasions and not my 97's. I gave Joe Abbins book to the machinist and told him to follow it to the letter. Like that short sighted, rather portly fellow in Jurassic Park, I spared no expense. I have been driving the car on the street for several years and other than a few fouled plugs, it will KEAL! I have friends that boast breaking 200 with normal induction. HP = $'s when building fast engines. HP = $$,$$$ when that engine is a flathead ford. Your friends at Jack Daniels ask you you to please build responsibly.
Found another YT vid where they dynoed a blown flathead. Must be from 2001 (Powernation - Horsepower TV Season 2/Ep 1). Made 260 hp. Loved Horsepower TV. Just learned that Joe Elmore passed away last year at age 80.
Stock block 1950 Ford flathead 292 cubic inches burning gasoline normally aspirated with two deuces running at Bonneville Speedweek 2024 ride along. Some details car weight with driver 3000 pounds. Mile three 5700 RPM , density altitude 7700 feet, outside temperature 100 degrees. Record run speed 159.919 MPH driver Carlie Moody rookie 2024 third run ever on the salt. New Land Speed record 158.767 Old record 140.735 Ronnieroadster
i'm a shoebox guy. my stockers would accelerate from 5 mph in high; ran one with an isky 400jr, and it really went above 40 mph; below that, nothing!
Hello, My first purchased hot rod was a Flathead powered 1940 Ford Sedan Delivery. As much as the Flathead was shown in some magazines as the power for early hot rods, we saw more SBC motors than any amount of Flathead motors. My Flathead was stock and it was put in place as a replacement motor for a powerful 348 Chevy motor that was originally in the sedan delivery. if I had enough money to buy the completed 348 powered sedan delivery, it would have been a great combination of our 58 Impala sitting in the garage and the 348 sedan delivery out cruising and going to the beach. But, it was not to be. I did buy the same sedan delivery, but it had a stock Flathead for power. So, a 200 hp drop to 80 h.p. that initially set me back a little, having driven our 58 Impala with 280+ hp for power. The adventures along the So Cal coastline and forays into Baja, Mexico wave spots was worth it. The Flathead was under powered, but a reliable road trip cruiser with a built in overnight accommodations. Locally, there were two steep slopes on Coast Highway. One from Corona Del Mar to Laguna Beach and the same road coming back to Corona Del Mar along the coastline. The road is right on El Morro Beach and the steep slope always needed a full “pedal to the metal” action on the downhill slope. If enough speed was reached, then we made it over the top. But, if there was traffic, it was down shift to 2nd and chug up the hill. There were days of brake action from other drivers and that made me shift to 1st, just to get over the top and into our direction going South. It was the same thing coming home. YRMV It was fun to drive to Reath Automotive as they always had a powerful 2 carb stroked Flathead motor fully functional on a motor stand. The polished heads/nuts/bolts and short chrome headers was a motor to die for as it had a stroked Reath Crank, powerful cam and more power than we needed, but it would have been a nice motor to have. Although it was well beyond our pocketbooks. They were well known to have at least 200 hp and that would have pushed me back near to the original 348 motor. Jnaki Every time we stopped at the Reath Shop, that Flathead motor stared us in the face and more thoughts ran through our heads… But, the reliability of the stock 80 hp motor was ok for flat streets. So, that limitation made us not go up the steep local mountains on snow ski trips. It would not have been a pretty sight struggling up the steep slope and sharp curves in first gear. Note: the two other So Cal coastline downshifting to 1st gear were the Conejo Grade out of Camarillo heading into Los Angeles from Santa Barbara. It was definitely a first gear climb. We actually got shooed off of the freeway by the CHP one time heading into Los Angeles. We had to take the coastal route, which was much better, but took longer. So, we were late in getting home to Long Beach. The other long hill climb is the Del Mar coastal roadway heading into Torrey Pines. If we got a good running start with a clear roadway ahead, we could at least only downshift to 2nd. But if traffic was a hindering factor, then a slow 1st gear climb was necessary in the slow lane. If we surfed at the base of the Torrey Pines Hill Climb, then it was definitely a 1st gear climb all the way to the top. The slowest portion of the So Cal coastline road trip anywhere going South towards San Diego beaches and Baja Mexico.
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