I bought this engine from an old hot rodder in 1978 for my dads 36 ford sedan. He sold the sedan and now I am finally using it in a 32 High Boy. 59 block, Offy heads, two 97's, winfield cam, 4" crank and 3/16 over pistons. Tore it down a while back and am now reasembling it. Noticed the real speed secret, 1952 S pennies in the heat risers. Does anybody still do this. Tim
I did it but with welch plugs, and in the intake manifold passage. I had trouble with cool weather running with it that way and drilled the plugs with a 1/4" drill. It's amazing how cold the carb gets even in 70 - 80 deg weather.
I did that on my 1946 Ford in about 1958, it sure made the pipes rap and crack! If I remember correctly, it earned me a " loud pipes" ticket. Bob
We used to do that in our race car motors around 1960 as the heat riser passages weren't really needed.It does raise havoc with the running on a street engine in cool weather. We were running 1/4 mile(or thereabouts)ovals and used to try everything to keep the engine cool during the races.The biggest problems we had was the coolant not staying in the radiator long enough to actually cool.We tried using restrictors in place of thermostats;knocking off every other blade on the water pump impellers and drilling holes in the remaining ones and even running a smaller diameter crankshaft pulley and they STILL overheated!We ran straight alcohol in the radiator rather than anti freeze(this was long before the availability of special coolants). Being that virtually no modifications were allowed(save for the ones we thought we could get away with)it could be difficult.
An older friend talked about slipping shim stock in under the flathead intake to make it more rappy. I got real excited and went to look at my 2 deuce intake and the old race car intake did not have the heat riser passage. I was heart broken. it was as rappy as it was going to get.
You're supposed to use pennies from the same yr as the engine and have them heads up for luck. I had 2 1951 pennies on my stroker '51 Merc. V8.
When I re-did a 59A block for a local guy about 15 years ago he told me it was out of his old High School car and the pennies were from the year he and his brother originaly put the engine together. Heads up 1951.
This was a very old build done in Glendale-LA area on so cal. I am sure that it was built in 52. I will leave the pennies in cus I hate to let the Genie out. Tim
I remember the old guys at work where I first started mentioning this when I was putting a Yblock together for my 56. Didn't have any square coins so I used a piece of sheet metal.
Back in the day if a flathead had loud duals it was a given that the heat risers were plugged. And, pennies were the plug of choice.
Amen Brother! It makes good cents! Resourceful hotrodders... makes a guy proud... making those kind of performance improvements for just pennies (literally)! I love what you found!
Educate me on the purpose of blocking off that port and why in the world would blocking of a heat riser to the intake cause the exhaust to get louder? I'm completely unfamiliar with this.
Count me in as someone who doesn't get the science behind the volume increase. I understand the power increase from a cooler intake charge, but louder exhaust?
Its a pressure impulse thing. Think of it (the exahust riser port) as a crossover pipe that reduces the exaust pressure impulse of the four middle cylinders all sharing the same exhaust port. This lessons the direct impulses to each muffler. When you plug the riser you direct the note two either side thus making the muffler handle more impulses. I dont know if that makes cense but I understand it. I think the performance is increased by getting more of a scavaging effect. (or as much as you can from a flathead) I am sure someone else can explain it better.
We used to just stick a piece of a beer can cut out with snips under the gasket. Does the same thing. I have some copper stock and a flathead I am assembling this winter. Hmm...
Keep this in mind, you must use only 1951 pennys with the heads up. Don't ask why. It's just the way it is. Look at the proof. That's why all pre 1951 flattys ran crappy. Those damned Indian Head pennys aimed down screwed up the flow.
Precisely! Result is a much sharper exhaust rap and it starts rapping at a lower RPM. It might have given a couple of extra HP, but that's probably wishful thinking. I never noticed any negative effect other than a little stumbling until the engine warmed up.
I recall my cousins doing this to their flatheads in the early 50's. Said it made the exhaust louder as Max above mentioned