This post is for John Mummert if you're out there watching

  I notice when you are advertising your cams you give the lift of each grind. What ratio are you using, 1.43 or 1.54.  Just curious

Bud in Northern Arizona on route 66 in Winslow (standin' on the corner)

If you're American, buy American

631/2 Galaxie 500XL 406   55 T-Bird

Bud, I use the 1.54:1. Specs vary a lot because some cam grinders use 1.50:1 for Y-Blocks. Most give spec without the valve lash taken out. This is gross lift. Also, most cams come up .002-.004" short of the grinders listed lift. So if they're claiming .300 lobe lift the cam will often measure .295-.297" actual lobe lift. Then wether you calculate rocker ratio at 1.43, 1.54 or 1.5 plus with or without lash and claimed lobe lift or actual lift you can see the numbers can be all over the place.

An example would a cam with claimed .300" lobe lift X 1.54:1 = .462" valve lift. But the cam measures .296" lobe lift and has .019" lash. Actual lift at valve would be .437".

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Thanks for the explanation John, appreciate your time and your great knowledge.

Bud in Northern Arizona on route 66 in Winslow (standin' on the corner)

If you're American, buy American

631/2 Galaxie 500XL 406   55 T-Bird

John,

The grinders could be figuring in the oil film on the cam, which could be up to .003" bringing the lift back up to their spec?

Just a thought.

55 Vicky & customline

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