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cuzncletus · 12-29-2011, 08:35 AM

Obviously the problem with making horsepower in a flathead is flow both in and out through some very convoluted passages. I'm with JM 35 sedan. I used the 1.6 Manley Chevy valves and lots of port work. There are three ways to get gasses into or out of an engine; volume, velocity, or pressure. I'm not running a blower so pressure is out. Velocity is an impossibility in a flathead because of all the turns creating high pressure zones. The only route left is volume. The additional room around the diameter of the valves plus the reduction of the stem to increase flow near the valve have got to help some. Argueably there could be some reduction in torque with reduced velocity at low speeds but flatheads are basically tractor motors; little torque monsters as were most engines of their day. Can you overflow an engine? Of course. Ford fans have to look no farther than the FoMoCo muscles engines of the late 60's/early 70's. Boss 302's and 429's were street dogs. Every roundtracker knew about epoxying up the intake passages on 351 Clevelands to increase intake velocity. But overflow a flathead? I don't think it's possible.

Just my two cents..........

12-29-2011, 08:35 AM	#19
cuzncletus Senior Member Join Date: Aug 2010 Location: Sevierville, Tenn. Posts: 391	Re: 1.60 chevy valve quetions Obviously the problem with making horsepower in a flathead is flow both in and out through some very convoluted passages. I'm with JM 35 sedan. I used the 1.6 Manley Chevy valves and lots of port work. There are three ways to get gasses into or out of an engine; volume, velocity, or pressure. I'm not running a blower so pressure is out. Velocity is an impossibility in a flathead because of all the turns creating high pressure zones. The only route left is volume. The additional room around the diameter of the valves plus the reduction of the stem to increase flow near the valve have got to help some. Argueably there could be some reduction in torque with reduced velocity at low speeds but flatheads are basically tractor motors; little torque monsters as were most engines of their day. Can you overflow an engine? Of course. Ford fans have to look no farther than the FoMoCo muscles engines of the late 60's/early 70's. Boss 302's and 429's were street dogs. Every roundtracker knew about epoxying up the intake passages on 351 Clevelands to increase intake velocity. But overflow a flathead? I don't think it's possible. Just my two cents..........