hugoct wrote:J cams time in at intake 66-66, 312 duration, 90 lobe center .395 lift, and exhaust at 58-42, 280 duration, 98 lobe center, .395 lift,
K exhaust is 58-42, so the same as J exhaust (why the change in designation?)
L exhaust is 65-40, 285 duration, 102.5 lobe center, .395 lift
M exhaust is 60-42, 282 duration, 99 lobe center, .395 lift,
I have Ms in Reiman's 1969 Daytona motor
The J/K combo are the H cams with less lift.
Thanks for the new information on the “M” exhaust lobe. From the opening/closing numbers you provided sounds like it falls right in between the J/K and J/L cam sets.
Not being nit-picky or argumentative, but some of the numbers you’ve quoted above do not agree with the published data I’ve seen on the KR cams. Specifically, the exhaust numbers I see posted for the 1967 J cams, 25499-67R, do not agree with yours, as the numbers I see are 0.395” lift, opening-closing of 65-40, 285 duration, and 102.5 lobe center. The numbers you’ve quoted for the J cam set is actually the data I see for the J/K cam set 25499-69R (as shown in the table posted above).
I believe we could also say the J/L cam set, 25498-69R, is possibly the same as the J cam set, 25499-67R, since the timing numbers are the same.
Although I use the opening/closing numbers for a given KR cam profile to extract all the same info you do, I have to admit I've never had the opportunity to degree any KR cam with the exception of the KHK, which I believe to be the same profile as the -53R cam, but with 0.375” lift rather than the KR cam with 0.395” lift. I am therefore always concerned when performing these extrapolations from only 0.010” lift opening/closing numbers, i.e., suggesting 2 cam sets are the same, assigning lobe centerlines and lobe separation angles, overlap, etc, since the low lift opening/closing tell us almost nothing about the actual shape of the lift curve, i.e., the lobe symmetry, the lift rates on the opening/closing flanks, etc. I wish I had a pile of KR cams to degree and overlay the lift curves to see how they actually compare, but alas, have never had the opportunity and know nobody that has such information available. I do have a set of J/K lobes to mount so will at least have the opportunity to measure these later in the year. Do you by any chance have any actual lift curve data on KR cam sets?