Just curious, what are the specs roughly on say a 741 or 651 cam, they seem to be talked about a lot, and how do they fare reversion wise? Never really hear what exhaust folks are using with them.

Edit:looked up the specs,still curious about reversion in 651 or 691 cam. Looking at something similar except in a solid roller

both of those camshafts need non stock exhaust.they need dry or very close to it or they will revert.

I concur totally. It's just an oddball configuration that will throw people unless they look at the entire cam profile. I think the .050" duration is like 196 on the intake for this cam.

that engine must idle as smooth as a piece of glass.

What matters is how long the exhaust valve is open ATDC during overlap. If you do a search, I have many cams, including the popular blue motors, showing specs including overlap #'s.

Even if not shown, overlap is easy to calculate - it's the # of degrees from when the intake opens to when the exhaust closes. ie: IVO to EVC.

Way back when, Crane said it's easy to get into reversion issues when overlap at .050" specs exceeds 6 degrees or more.
Again, if not stated, most cam companies with show events at .050" also. Take how many degrees from IVO at .050" to EVC at .050"

Yes, it's 196/206 at .050" with 109LSA. Overlap at .050" is a negative number. It's a truck cam...literally.

sb,i was going to include that info but i am way to lazy tonight.

LOL.

Tomorrow, being Monday, I had to release some info from my limited grey matter so I'd have a few brain cells free'd up for work . hah !

Oh, I know and they used them in droves for nearly every EFI SBC marine motor from Merc to ski boat motors.

It does idle smooth. Pulls strong in the midrange then falls on it's face above 4000-4200 rpm.

that is good information,the overlap is what causes reversion, the lsa is just the placement of the cam lobes.