Ill stick with 280x4 to be sure,or the sparks cam..

 

The Sparks Hi Rev is the Mega Cycle 280X4, give or take .030 of lift difference between all of there cams.[img]i/expressions/face-icon-small-wink.gif[/img]

 

Me no understand.[img]i/expressions/face-icon-small-confused.gif[/img]

 

so they are not the same..? I guess we will find out soon..

 

I was under the impression from a previous thread on this topic that the x4 was similar to the sparks mid range cam, and the x14 was similar to their top end cam. I know that the sparks high cam is great for top end, but lacking in the low.

 

No they are the same cams, Mega Cycle, and Web cams are not all the same. In other words the company's are not consitant with there machine work.

If you get two 280X4 you will find some small difference between them, just like the 685 Web cam. We have check two Sparks Hi-Rev cams and found .030 difference between them and both were stamped 280X4

 

Thanks for all the repley's! Does any one know off hand if you need to Machine the valve reliefs with a 280x4? I know I still have to check the clearences on each application just wanted to know so I could plan on tearing it down farther than just the valve cover.

 

I would cut about .040 thousands off the middle intake valve guide as well as the valve seal. It is always a good idea to do a valve relief check to make sure the valves and pistons don't make contact under full throttle, thumb of rule at least .080 thousands clearance between the valve and piston.

 

Ernie, Removed enough material off the center intake valve guide to allow the seal to bottom out on the head. Which is probibly not enough for this cam. I run a 12:1 102mm JE and assume that for the most part the valve reliefs should be enough to not run down a guy to fly cut them for me unless I measure under .080.

 

Good info guys ,thank for the help also...