MILD THUNDER

Short changing an engine on duration, is just as bad, if not worse, than short changing it on lift. Somehow, we have all been trained that duration is bad, lift it good.

I'd be willing to bet, Full Force tim's engine, with the proper duration, and say 630ish lift, will kick the 680 lift , short duration cam's azz.

I have heard guys say, "no need to go over 650 lift if the heads don't flow any more air at 700 lift than they do at 650". IF you stick a cam in a combo like that, it will still make more power with the 700 lift cam. Why? Because a 650 lift cam, is only at 650 lift for a small amount of time. A 700 lift cam, will have more time, from the point at which the valve is coming up to 650 lift, going past 650 lift to 700, and again going past 650 lift on its way down.

also, as I have said before, just because a cam makes it PEAK HP at 5900rpm, doesn't mean that if you go to a cam that makes PEAK hp at 6300RPM, you will have LESS power at 5900RPM, as the first combo. The cam gods make you think that if you ask for a cam for a combo that you are gonna prop to 6000rpm, and it peaks at 6000 on the dyno, then you just struck gold !

MILD THUNDER

Comp also offerers their marine cams, in a high lift version. You wont get a .400 lobe, with 241 duration though, not from them or crane, lunati, etc.

If there was no downside to short duration, high lift, we would see 224* degree cams with .400 lobes.

When paging thru some of the big cam companies lobe series, even for solid rollers, anything labeled "endurance" or "marine" , will generally have less lobe lift, than a drag race profile, duration being equal.

getrdunn

MT you got me thinking about this in regards to optimizing build with heads that flow well way through .700 then say flatten out btwn .700 and .800. In comparison to what you mentioned above would you apply the same principle. Select a cam .725-.750. I would imagine at some point you need to cap lift as duration will increase as well but just don't want to get to high above running rpm with max hp say for instance like peak hp numbers up near 7k when your propping to 6k. Don't get me wrong I understand the continuing to make power above running rpm. Most my builds exceeded power above where Ive propped.

Otherwise any thoughts on pushing the limits on duration within reason to get most out of build possible and advance cam to bring power peak power down to a more desirable rpm. With many grinds already having advance ground into them 4 plus or minus... Where do you draw the line on how far to advance cam if where to do so. I've never been more than 8 deg total. Just looking for insight on such. Any thoughts?

getrdunn

In addition to above post what if heads flow well up to up to .800 with worthy gains btwn .700-.800.

Now that I think of it black baja touched on this somewhere along the line here in this thread or another. At what point is to much when it comes to advancing a cam due to piston location vs valve timing events?

articfriends

Im getting ready to assemble my old bajas 540 long block na w a 252/259 cam .660 lift, doesnt have really enough compression to support the cam but going to run it anyways on my dyno just to see how much hp it willake, afr 315s that been re cncd to flow 400+cfm, previously made around 650 hp na w a modded 502 mpi intake on this very set up, i plan on playing w cam timing on the dyno, intake swaps, mods, etc

articfriends

Starting out w a modified procomp/speedmaster open plenum intake w 2200 cfm dominator style throttle body

BenPerfected

Will you have the necessary valve size and lift to take advantage of the 400+CFM?

getrdunn

If I go hyd I may try this and see how it works out. 253/259-680/680 on a 112

sutphen 30

that cam looks interesting,,in good way.go for it.

MILD THUNDER

I would call howard, and get the cam on a billet core. Im pretty sure that for that price, its on a sadi core