63 f100 292 .060 overbore G heads standard trans

lookin at a isky rpm-300 or mummerts 270 grind. Have read that the isky E4 is pretty mild.

lookin for comments on these grinds. lookin for a cam that will still have some low end power.

RPM-300/duration 270/lift .448/112 centerline

mummert 270/duration 272/lift .440/centerline 108 

Kenny  Onalaska, Texas

Afraid I’ve got the Isky E4 in my 272 so can’t help you on the other two grinds.  But the E4 literally boils the hides with it installed at 104° intake lobe centerline.  The E4 is slightly more duration and lift than the factory ’57 cam but is ground on a 108° lobe centerline which makes for more peak torque than the factory grinds.

Lorena, Texas (South of Waco)

Hey Ted, I remember seeing an advertisement for that grind from Isky (E4) about 10-15 years ago - maybe it was Red's? Anyway, do you know of anyone still carrying that grind?

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Ted; viewed all the cams listed for Y-blk by Isky. Why do they recommend such high spring pressures? The E-4 is listed as needing 135 LB on seat & 285 open with damper.. same as the 505 T. It would seems unnecessary on a cam with a range from 2000 to 5000. ??

Paul

   Everybody seems to be running the Isky or Mummert cams,I've got a 272 y-block that has a Crane cam grind#S-264-C, any info on lift/duration and performance compared to the above type cams?  KID

Paul. Isky only lists one valve spring for the Y and that particular part number is also used on several other applications. My own experience is that too low a pressure is as bad if not worse than too much. Seat pressure is only a part of the overall picture as it’s the over the nose pressures that are the real detriments in regards to cam lobe and lifter wear. If installing the Isky 6005 springs at 135 lbs of seat pressure for the E4 camshaft, the over the nose pressure will be less than 250 lbs which is an easy push for the Isky cams. But have to agree that 135 lbs of seat pressure on a daily driver Y is to the extreme so just back off on the pressures either by removing the center spring or going with a taller installed spring height.

I’ve the 6005 Isky springs in my daily driver 272 and they were originally set up at 110 lbs of seat pressure and now have over nineteen years on them without any camshaft issues. The Y engine in my roadster is using the Isky 8005 springs installed at 135 lbs of seat pressure with over the nose pressures being in excess of 370 lbs with the same zero lobe or lifter issues. If the camshaft is of good quality and the oil is adequate, lobe and lifter life really isn’t much of an issue in the Y even with extreme valve spring pressures. I think Gary can chime in here and give some additional information regarding lobe rakes as that's also a valid player in camshaft life. For myself, the base circle diameter is a much bigger player as the lifter drop from the bottom of the lifter bore becomes more critical as camshaft base circles are reduced.

But I recently dynoed an engine with 200 lbs of seat pressure on the flat tappet hydraulic lifter cam and upon pulling the cam to install another cam of slightly different variation, the original looked flawless after making several pulls. And this cam had already been run and raced in the car when it arrived at the shop. But the lifters were extremely hard on their bottoms. So hard in fact that the warning with them is to make sure they always stay in contact with the lobe with absolutely no chance of bounce. Hence the high valve spring pressures for this particular camshaft.

Here are some other past threads regarding Isky valve spring pressures.

http://forums.y-blocksforever.com/Topic20831-3-2.aspx

http://forums.y-blocksforever.com/Topic16506-3-1.aspx

Lorena, Texas (South of Waco)

Crane S-264   Hi-Torque Road-Track-Drags

Intake open/close  26-58

Exhaust open/close  72-12

Advertised duration 264°

Duration at 0.050” Int/Exh 220°/220°

Lift with 1.54:1 rockers Int/Exh 0.445”/0.445”

Lash hot Int/Exh 0.016”/0.018”

 

Based on the open/close specs, it’s ground on 113° lobe centers

Lorena, Texas (South of Waco)

thanks for the help on the original topic.

Kenny  Onalaska, Texas

how does lobe centerline affect idle and low end power.

say 112 versus 108.

Kenny  Onalaska, Texas

Thanks for the info Ted, dug around in some paperwork and found the cam card. Listed as "mechanical special-regrind #00358--S-264-C " Intake open/close 28/64, Exhaust open/close 74/18---Advertised duration 272 degrees-- duration at 0.050 Intake/Exhaust 222/222, Lift with  1:54 rockers Intake/Exhaust 0.445/0.445 seems to be a nice streetable cam with a little lope to it at idle ! Again-- Thank You for taking the time to answer my question. KID