Cam reccomendation

[Drew]

Running a 525ci aluminum Dart heads with CMI exhaust with blower. Looking at starting with 5-6 lbs of boost. Have had a Crane 139651 Hyd Roller cam reccomended. This cam has 244-256 duration @ .050 abd 632 lift. What do you run? Seems like picking the cam is the hardest part besides the $$$$$$ http://free.***boat.net/ubb/biggrin.gif

[Infomaniac]

Drew: That is a very big cam. Does not come in until 3800 RPM.This is a stern drive boat? It will not be friendly to putting the drive in gear and idling in no wake zones.
Picking a cam is one of my specialties. What is the max RPM's you will run?

[Drew]

Should see about 6000 max on a short burst but 5600 would more likely be the norm. I know it is easy to over cam a motor. This is a blower motor. I know the idle with that cam in a 540ci I had was not to bad. Thanks.

[Infomaniac]

Drew: I would recommend the Crane 134241. It will not sound as cool at idle but will perform the best. Much better low end also.

[VD CRUISER]

Infomaniac,
Been trying to get a cam reccomendation, see my post "1000 + HP", on this board. Got a lot of good information, but not much specifics on a cam. What do you think?

[Infomaniac]

VD Cruiser: I read your first post and did not throw in my 2 cents because I did not see the application for your engine. I now see it is in a v-drive. Also It did not look like you would have any trouble making that HP with the engine components you had listed.
Superdave uses Clay Smith cams and if he uses them I am sure they are good. Exactly which one to use? you need to call them.
I have a Crane in my v-drive. Not as much engine as you but it makes 1000 HP. It is not pump gas, Injected alcohol.
I use the Crane 138791 RPM range 3800 - 7200 solid roller. It makes good torque and midrange to pull the gears you have.
Do not use a hydraulic cam with the RPM's you intend to run

[Drew]

Thanks Infomaniac; I was thinking more in the lines of a 139741 possibly. Want to stay with HYD roller cam. What is the max you would turn a HYD roller. Thanks

[Infomaniac]

Drew: I am so sorry. I am at work trying to overhaul a Boeing 737 and talk on the board at the same time.
The cam I meant to recommend was the 139731. Same grind of the other one I recommended but roller.
The reason I picked this one rather than than the one you are looking at is the RPM range of the cam.
There is 500 RPM of wasted range in the 139741. That is 500 RPM of useful range down low that you could actually use. If you are going to turn 6,000 RPM max and most of the time 5,600 I would not get a cam that peaks at 6,500.
You would be much happier with the low end and mid range use. You can always turn an engine a little bit faster than the cam RPM range, but too big a cam hurts bottom end and mid range.
Hyd rollers are OK to 6,200 - 6,500 for brief periods with good lifters. Any more than that and the spring pressures required for those RPM's kill the hyd effect of the lifters.

[Drew]

One thing to say CONCENTRATE ON THE AIRPLANE. http://free.***boat.net/ubb/biggrin.gif We all will fly happier. Just razzin and thanks.