Hi guys,

I have just received a pair of heads from a very kind Y Blocksforever forum member and fellow Y Blocker Jumpstart (Bob) bloody legend!

Anyhow, I’m trying to figure out what ratio rockers are on the heads, I believe one set is the 1.54 due to the ECG6564B2 stamping and the other set is an aftermarket replacement 1.43 (no stamp) according to John M’s website.

After searching around the posts, I found the 1/4 and 5/16 inch drill bit method that Ted suggested and gave that a go. The aftermarket rockers fits the 1/4 inch bit loosely but the 5/16 won’t fit.

I also tried the method Unibodguy suggested which was measuring the length of the rocker, apparently the 1.54’s are 3 inch and 1.43’s are 1/4 inch shorter

Not too sure though, so I though I’d throw up some pics and see if you guys have any ideas?

ECG6564B2


1/4 inch drill bit test (bit tight- doesn’t exactly fit)




Aftermarket rockers



1/4 inch drill bit test (fits loosely)




Also one last question-
Does it matter if the rocker area that contacts the valve spring (unsure of the technical name) is slightly off center to the spring?



Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.