420 cyclone cam replacement
 

Does anyone have any thoughts on using a Lunati 60204 hyd flat tappett cam for a replacement?? It looks to be just a bit bigger on intake and a bit smaller on exhaust, comes with a 110 lobe seperation and a 106 center line. 52 degree overlap -- so reversion should not be a problem.

233/241 @ .050
.554/.572 overall

They said they can custom grind it to a 112 seperation -- is this necassary?

Or what other cam choice would be good -- trying to stay away from crane as i have seen too many get wiped out new

850 cfm Holley
Team G single plane intake
stock merc exhaust
t-bolt ign
.030 over


Thanks in advance.

Dave

Re: 420 cyclone cam replacement
 

When you say stock Merc exhaust, do you mean stock cast iron. or stock Merc/Gil?

Re: 420 cyclone cam replacement
 

stock cast -- I realize that they are not close to the ideal -- but that's what these engines will have. :rolleyes:

Re: 420 cyclone cam replacement
 

ttt

Re: 420 cyclone cam replacement
 

I will jump in here not as an expert by any means but I wonder about that overlap number. Was that figured at .004? My much milder cam 224,232 .527.553 at 114 sep has 75 degrees of overlap. I dont see how that flat tappet you listed could only have 52 degrees overlap. If it were a roller, then Id believe it. Could you post all the cam card numbers, ie timing at .004?

Re: 420 cyclone cam replacement
 

Formula31,
Lunati rates adv duration @ .006"
The 60204 on a:
110º LSA and 106º ICL = 60º overlap
112º LSA and 108º ICL = 56º overlap
Bob

Re: 420 cyclone cam replacement
 

Sorry my mistake I typed in 52 instead of 56.

Rmbuilder --- does this seem like the right cam for this application?? Or would there be a better one?

Re: 420 cyclone cam replacement
 

ttt

Re: 420 cyclone cam replacement
 

In my opinion, 110* separation is border line and could lead to reversion especially with stock exhaust. 111* - 114* of separation would be appropriate. As the cam becomes more aggressive, it is especially important to pay attention to separation.

As far as a cam manufacturer, I've had good luck with Competition Cams.

Re: 420 cyclone cam replacement
 

delsol,
The seat durations on this Lunati are 12º shorter than the original Cyclone, the .050" are 2º longer. Overlap in degrees of rotation will be shorter, overlap area will be similar. If you have this ground on a 112º LSA it will give you an added advantage against reversion. These lobes are significantly quicker so be sure your valvetrain is up to the task.
Bob