The Ford Barn

3W Hank · 04-17-2024, 12:46 AM

About compression in a FH.
Old speedparts heads had high compression as the Canada heads and to Kogel both cast iron and aluminium.
So idea must have been that compression got a stronger engine.
But this engines had a terrible flow around the piston so one can questionise if not a lower compression get more flow to spark, so more power in reality.

I has a set of the ’10 to 1’ L&S heads and Ross domed pistons.
Heads is at 59 CC and measure 10.5 mm or 0.413” deep chambers.
They get 10 in compression with 1/8” bore and a 4” stroke and a 0.04” thick gasket in a 59BA.
My cam is a Potvin 425 ( 425” lift ) so I might get away with this.
But I might has to mill the chambers or go with a thicker gasket.

-So the question is, do this engine like compression or do they make more power less compression.
That would cure all piston to head and valve to spark plug issues aswell.

In my case I’m not after max power, just like the sound and feeling and old parts.
So question is more technical.

04-17-2024, 12:46 AM	#1
3W Hank Senior Member Join Date: Feb 2022 Posts: 145	Compression and flow About compression in a FH. Old speedparts heads had high compression as the Canada heads and to Kogel both cast iron and aluminium. So idea must have been that compression got a stronger engine. But this engines had a terrible flow around the piston so one can questionise if not a lower compression get more flow to spark, so more power in reality. I has a set of the ’10 to 1’ L&S heads and Ross domed pistons. Heads is at 59 CC and measure 10.5 mm or 0.413” deep chambers. They get 10 in compression with 1/8” bore and a 4” stroke and a 0.04” thick gasket in a 59BA. My cam is a Potvin 425 ( 425” lift ) so I might get away with this. But I might has to mill the chambers or go with a thicker gasket. -So the question is, do this engine like compression or do they make more power less compression. That would cure all piston to head and valve to spark plug issues aswell. In my case I’m not after max power, just like the sound and feeling and old parts. So question is more technical.