Technical flathead cylinder heads

I have been doing the head gaskets over on my 46 Ford. One side has a "made in Canada head with no other significant identification, looks like the 59 etc was ground off at some time. The other side is an 81A 6050-A . I can see a significant difference in the combustion chamber volume between the two. If I put it back as it was will the difference in compression ratio from one side to the other make much of a difference?. This motor has been like this for years, should I find another 59 series head or use another 81 series,, which I have two more of? Just got these back from the machine shop, they look like brand new, am dying to get my car back together. Any advice appreciated, Rich

 

Measure the number of CC"s of water each chamber holds.If its a big difference you might surface the larger head to bring it down in volume.If you do that check your valve clearance just to be sure its ok. Or just use a spare 81 head.

 

Is the Canada head aluminum? Look on the backside of the water neck for some writing. It may not be a Ford head. To try and cheat the stock car rules, Weiand made aluminum heads that looked like stock Ford Canadians, but were missing some ID numbers. And they said Weiand on the inside.

 

Cast iron head! milling down one head wont make up for the difference. what is the compression ratio on an 81 series head? as opposed to a 59 head? Rich

 

Look for this... it may be a weiand cheater head like alchemy stated.

 

Weiand had their own pattern for combustion chamber, different than most FH heads.

 

I'd call those "molar" shaped combustion chambers.

 

First thing to check is the cylinder bore. Some 59 type blocks were produced as service replacement blocks for the prewar 221 V8’s. In other words, they had the 3-1/16” bores versus the 3-3/16” bores of the regular production 1946-48 blocks.
Certainly the engine can run with mismatched cylinder heads but over the long term there can be issues with the wrong head over the bore......gasket issues for one.

I’d try to match things up......if it does turn out that the block is the 221 type, you’ve got the 81A heads on hand. If it’s the 239 block, I’d locate another 59A head......they’re not all that hard to find.

 

Thanks Mac exactly what I wanted to know Rich

 

Sometime after 1942 there was a change in the combution chamber. The valves were moved a little and the heads changed to match. The heads off a 59A 221 Cu in engine had to have the heads modified for valve clearance for use on the 59AB. To the rear, I think. The was special tool for this operation. These 59 series engines used a lot of different heads. It's rather confusing. Keep 'em matched is my advice.
I have this info in a 1942 factory service manual but it doesn't tell much more the what I stated here.