Help identifying cylinder head...

[markyb]

Can anyone tell me what compression ratio this head might be? I looked in some of the parts catalogs and the pictures aren't good enough to help me identify it. There are no numbers anywhere on it.

 

[TinCup]

Looks like a Snyder's 5.5 head. Notice the heart shaped combustion chamber it's a dead giveaway.

 

[CarlG]

Looks like a Snyder's 5.5 head. Notice the heart shaped combustion chamber it's a dead giveaway.

Also, the 2 little casting marks at the top of the third picure help solidify that statement.

 

[markyb]

Would a 6.0 head have a more shallow heart shaped chamber and look similar? Carl, which marks are you referring to, inside the chamber?

My new AER engine has a 6.0 head, nice to know that I have a bit of an upgrade, thanks guys.

 

[James Rogers]

You will notice on the driver side of the head on the top there is 2 small cast marks with 5 dots in them. This is a dead giveaway of it being a 5.5 Snyder.

 

[markyb]

Ahhhh, bingo, good eye, those marks are hard to see with an untrained eye like mine. The 6.0 head looks to have the same markings, although closer to the center bolt hole in the head. Is that the way they differentiate? It's the same circle with 5 dimples.

 

[Cajun]

Checking compression with the throttle open will give you a close guess on the compression ratio.

Data from F.A.S.T. Magazine

Ratio PSI

4.6 69
4.8 73
5.0 77
5.2 81
5.4 85
5.6 90
5.8 95
6.0 100
6.2 105
6.4 108
6.6 113
6.8 117
7.0 121
7.2 126
7.4 130
7.6 135
7.8 140
8.0 144
8.2 148