FullAuto

This has came up several times in the past few weeks so let's clear this up. SBF cams are generally rated with a 1.6 rocker. So when you see the FMS B cam with .480 lift, the lobe lift on the cam is .300. Take that .300 and have a 1.6 rocker and you get .300 x 1.6 = .480. With a 1.7 rocker you'd have, .300 x 1.7 = .510.

An E cam with .498 lift has a .31125 lobe lift. Now realize that the advertised numbers in catalogs are also generally rounded off numbers. The lobe is probably actually a .311 lobe. With a 1.6 rocker that would make it .4976 and they could possibly round to .498. But it also may actually be a .31125 lobe. This info shouldn't be hard to find, but I'm too lazy to look. Anyway, with a 1.7 rocker on an E cam, it would be .311 x 1.7 = .5287 or .529. If it really has a .31125 lobe, it would be .31125 x 1.7 = .529125 or .529 lift still.

The TFS site actually lists the lobe lift and the lift with 1.6s. http://www.trickflow.com/product/cam..._cams_ford.asp

As you can see,a TFS Stage 2has a lobe lift of .339/.352. With 1.6s this makes it .5424/.5632 and they round off to .542/.563. With a 1.7 rocker, this cam would be .576/.598.

Also, just because SBF cams are generally rated with 1.6 rockers doesn't mean everyone is. They are rated with whatever they came with from the factory. Most SBC stuff is rated with 1.5s, big block stuff with 1.7s, etc.

Clear as mud?

FullAuto

When you are trying to figure out how to convert from 1.6 to 1.7 ratio and you don't know the lobe lift, you take the advertised lift with 1.6... DIVIDE by 1.6 (to get the lobe lift), then MULTIPLY by 1.7.

stang8689

thanks for the info

my77stang

its so easy for us that understand it, sometimes its just as easy to forget others just dont know[8D]