Rusty O'Toole Posted September 8, 2011 Report Share Posted September 8, 2011 "The side valve design of the flat-head engines greatly impede the flow of the air-fuel mixture where-as the overhead design allows a more even unrestricted air flow. Buick, Chevrolet and Nash realized this early on." You should examine some actual engines of prewar design. The OHV engines had very restricted valve sizes, restricted by the diameter of the cylinder. The flatheads had no such restriction, their valves were larger and the valve chamber was wider than the cylinder. Compare size for size, Buick Chev or Nash to their leading competitors and you will find the OHV had little or no advantage, in many cases a good flathead had more developed horsepower and torque than the OHV. In postwar, big bore, short stroke engines there was room for larger valves and they took advantage of it. That is a completely different design philosophy. The postwar engines were the ones that overshadowed the best flatheads, which were by that time 20 years old or more. The OHV engines did eventually prove superior but not in the 1920s to early 50s time period. Quote Link to comment Share on other sites More sharing options...
Brianchaninov Posted June 17, 2016 Report Share Posted June 17, 2016 Iron piston/splash lubed Chevys were quick off-line but max about 4000rpm ie 80 MPH with stock 4:11 axle. Flathead V-8 Ford or Plymouth 6 would easily top-end any stock Chevys before they rec'd alum pistons, inserts, and pressure lube.(1953 Powerglide,'54 /stick.).Ford had optional overdrive and their 6cyl flat-head arguably fast as their V-8. . After blowing rod my '48 Chevy engine I replaced with a '54 block. Added Fenton headers, 2 carb manifold (Stromberg 97's),1/8" off head and port work, plus a 3/4 grind cam. It would really scoot easily beating all OHV '54-56 V-8 Fords and many Chevy V-8's at informal OK A&M Saturday quarter-mile runs Stillwater OK airport 1954-56. (those races were essentially unsupervised ---hard to imagine such freedom today but we had fun and none got hurt). 1 Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted June 17, 2016 Author Report Share Posted June 17, 2016 Iron piston/splash lubed Chevys were quick off-line but max about 4000rpm ie 80 MPH with stock 4:11 axle. Flathead V-8 Ford or Plymouth 6 would easily top-end any stock Chevys before they rec'd alum pistons, inserts, and pressure lube.(1953 Powerglide,'54 /stick.).Ford had optional overdrive and their 6cyl flat-head arguably fast as their V-8. . After blowing rod my '48 Chevy engine I replaced with a '54 block. Added Fenton headers, 2 carb manifold (Stromberg 97's),1/8" off head and port work, plus a 3/4 grind cam. It would really scoot easily beating all OHV '54-56 V-8 Fords and many Chevy V-8's at informal OK A&M Saturday quarter-mile runs Stillwater OK airport 1954-56. (those races were essentially unsupervised ---hard to imagine such freedom today but we had fun and none got hurt). Hi Brian, thanx for reviving my old thread, very cool post, Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted June 17, 2016 Author Report Share Posted June 17, 2016 (edited) BTW, post any old pics, of the cars ,engines and drag strips if you have any? That really adds to a thread like this. I just finished adding dual carbs and exhaust to my engine, but could see it being more lively with a shaved head and hotter cam. I have owned a few Chevy 216 engines, and a few 235s and 1 292, that 292 had lots of grunt... Edited June 17, 2016 by Fargos-Go-Far Quote Link to comment Share on other sites More sharing options...
dpollo Posted June 17, 2016 Report Share Posted June 17, 2016 Great nostalgia here. I have owned and worked on the Ford V8 and Chev 6 but always had a Plymouth for my driver. Seems to me I got more miles per dollar than my friends did from the competition. It was our duty as teenagers to find the weaknesses in our parent's generation of cars and my friends and I worked hard at it. It was easy to tear the transmission out of a Ford or Chev. many 216s would lose the pistons after a hard run and the left rear axle was a weak spot too. Me, I broke the top rings on 5 out of 6 after a midnight run of 150 fast highway miles with a 90 000 mile engine. Did not leave me stranded though and a re bore carried me another 60 000 miles in that particular car. Overdrive equipped. That was in 1968 and I still have the engine and the Overdrive is in another car. 1 Quote Link to comment Share on other sites More sharing options...
Robin (UK) Posted June 17, 2016 Report Share Posted June 17, 2016 (edited) This may be of interest. The results for the K class (full bodied cars) running vintage (V) flathead (F) engines at the VHRA Amateur Hot Rod Races at Pendine Sands, Wales, two weeks ago... No Speed Class Car 52 89.30 V8F/K 1939 Ford Sedan 57 86.33 V8F/K 1936 Ford Coupe 419 83.66 V8F/K 1946 Ford Coupe 382 78.41 V8F/K 1937 Ford Coupe 87 77.95 V6F/K 1947 Plymouth Convertible 235 77.18 V6F/K 1948 Plymouth Sedan 293 76.90 V8F/K 1936 Ford Pickup. 365 75.32 V8F/K 1939 Ford Standard 216 73.74 V8F/K 1937 Lincoln Zephyr 300 73.54 V8F/K 1939 Ford Tudor 412 72.71 V8F/K 1940 Ford Tudor 321 68.68 V8F/K 1947 Ford Deluxe 348 67.05 V8F/K 1946 Ford Tudor 90 61.95 V8F/K 1936 Ford Tudor 245 58.49 V8F/K 1941 Ford Pickup Cars are timed through a speed trap, after a half-mile run-up on the beach (sand).Dean and I did pretty well against those V8 boys! Edited June 17, 2016 by Robin (UK) 3 Quote Link to comment Share on other sites More sharing options...
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