I was browsing through the Ford technical information part of Mr. Gasket's website. Several pages into it came to some data regarding Erson cams in Y-blocks. There were 3 or 4 cams offered, and it said that the advertised lifts were as stated using stock rocker arms of 1.47 ratio, and that if the 1957 rockers with 1.54 ratios were used, lifts would be proportionately higher.
This is a mistake isn't it? I have ALWAYS heard, read that all the non 1957 rockers were 1.43.
www.mrgasket.com/ftp/pdf/Ford.pdf
(on page 5)

 

Mike,

1.43 ratio is the lower ratio offered. Alot of cam manufactures use 1.50 as a industry standard. Probably because they figure MECHANICS cant figure lift at 1.43 or 1.54

Kevin Bigwin

 

So they must have pulled the 1.47 out of their but*. Wonder if that was Erson or Mr. Gasket. If Erson, also would make you wonder about their cams for Ys.

 

I'm running a ERSON cam.I'll look for my cam card and see what it said. I think it listed the actual lift then you had to do the math with your ratio rockers. I'll check

Kevin Bigwin

 

I'm not sure that one can get very dogmatic about the ratio, other than to say the 1.54 rockers do have more lift than the 1.43 ones. Two factors that can alter the ratio are the installed valve stem height and the length of the pushrod.

These two factors and other production line tolerances make the exact ratio hard to figure unless you get your dial indicators out and actually go at it. So, picking a figure like that out of their hat is probably close enough for horseshoes and hand grenades, if not actual government work.

One thing I can say is that there IS a difference between the two ratio rockers, and this difference is quite evident if you have them side by side. The pushrod side of the high lift rocker is about 1/8" shorter than the normal arm.

I carry an old high lift rocker with me on my junkyard forays, because rockers are often too nasty to read any numbers on them. But putting my high lift rocker next to whatever is in the car will sort it out quickly -- just gaging by eye.