I am considering installing a different cam for my 91 Cu in. shovel 4 3/4 stroke
a couple questions.
I see there are different part numbers for 1970 to 77 and 78- 84
what is the specific difference in the two?

I have installed the Sifton "109" .440 lift
engine is 9 to one compression
in a rigid frame bike with a 5 speed
any suggestions for a little more cam without having clearance issues?
would the Andrews "6" be a good choice?
thanks for any suggestions

 

will if figures after I posted I found this info.

 

J4 Intake: 44/82 306 0.502 Exhaust: 75/38 293 0.485 Overlap: 82


leinweber

 

if the sifton is a real one and not a tiawan tedd made in some communist **** hole with the gear pressed on any place it fits

in my stroking of these motors we always kept the lift short and the duration long - as that kept the wear to a minimum and that cam make real good power everyplace in the rpm range -

the A6 was replaced with the 7 and idont care for ether one // but they look good on paper

for me 9 to 1 is a bit on the high side but that sifton will reduce the static compression and make it ok to kick - shorter duration cams will make it harder to kick /// it all comes down to when the intake valve closes ( amount of duration ) and how much air is trapped in the bore you need to compress with your leg

 

thanks for the replies guys.
I didn't personally check the compression by CC'ing the chambers..
the previous owner of the stroker parts said it was 9 to one?
I don't have a kick start on the 5 speed trans. couldn't use it if I wanted to with 2 bum knees.
I was told the Sifton cam was USA made for what it is worth the box it came in said made in the USA.
After changing the lifters to solids the engine runs much better so I will leave well enough alone and run the Sifton.
The hydraulic lifter inserts fit loose in the bores of the Jim's rollers and the solid conversion inserts I had were to large diameter to fit in the Jim's? never ran across that before so I swapped out the rollers for OEM and the solid conversion inserts which fit the inside bore. This took care of the noise I was hearing and the engine runs much stronger now just have the solid clatter noise. I can live with that for now but eventually would like to go back to hydraulics of some type. I would like to hear the pros and cons of the Jim's power glide and other options before spending the money.

 

stay with the old school stuff oem lifters and solids for that cam - jims stuff is all junk today its been out sourced tools and parts he made a name now it time to really collect they think