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If you want to go fast and rev it higher than 6000rpm, install a mechanical roller cam and lifters. Hyd rollers are famous for giving up the ghost somewhere between 5200 and 6000rpm on BBC's because of the heavy valvetrain and heavier retrofit roller lifter mass.. A lot of guys end up running solid roller lifters on their hyd roller cams
(.001-.002" lash) when they find out the hyd roller lifter has a serious rev restriction (brick wall). We just did a solid street roller upgrade from a hyd on a 396. Nice increase in power and rpm capability. Comp has complete install kits (extreme energy mechanical street roller) with springs, retainers, locks, seals, pushrods, cam, lifters that when you add it all up are reasonably priced kits. These are not hard to adjust the lash or keep adjusted. You have to listen real close to tell its a solid cam when the valves lash is adjusted correctly. When setting lash on a cold engine I like to adjsut the lash .002" tighter than cam card spec on these cams. I recomend you do the same. The lash opens up just slightly when a BBC warms up to operating temp. But the superior rpm capability of a solid lifter valvetrain on a BBC is significant. When you buy used, you are getting someones cast off stuff. Save your money for the real deal and let someone else run the girlie - man stuff. Last edited by F-BIRD'88; 07-26-2009 at 06:03 AM. |
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Thanks for the Input on that F-Bird, So your saying I'd be better off going with a Mechanical Roller Cam kit. I was looking at them just now, and looks like the kits ARE decently priced compared to the hyd rollers. And I don't think I'd have any problems with the maint.
Is the Mech roller still suitable for street driving? Which name Cams would you recommend? Comp? Lunati? Crane? etc.? What kind of specs would you recommend for a street driver car , with possible occasion to the strip? I also like the lumpy idle, would that have to do with the lobe separation? first engine build for me so everyone's input is very helpful Thanks |
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I use a custom ground solid roller cam in my 99.9 % street driven 468 big block,heres the specs;
Duration @ 0.050:243/249 int/ex Lift:.668 in & ex 112 degrees lobe seperation angle This has a real nice sound at idle,and works up to 6500 rpm.Its got a nice torque curve,517 ft/lbs @ 3500 rpm,440 @ 6500,with a max of 520 @ 4200 rpm.There is enough vacuum for a couple of pumps of the brake pedal,but I use a manual tranny,so its no problem for me.Using quality parts will help with valvetrain longevity,the old saying "you get what you pay for",really does apply here.The proper matching valve springs is critical,as is proper installation.Off the shelf Comp roller cores are ground on a cast core,and should be avoided if possible,although they can be custom ordered on a billet core.Crane is no longer in business.The Lunati Voodoo is a good line,maybe one of the better,(best??),off the shelf line of cams.The same gentleman that made my custom cam also designed the Comp & Voodoo cams,with the Voodoo line being his newer design.As for checking lash,I do it once a year,although this is a summer only car,with 4-5000 miles put on it a year.As F-Bird said,be careful of used valve train parts. Guy |
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These cams were designed for steet use. The reason they use a cast core is price. The reason they are able to use a cast core is these cams are able to run with reasonable modest spring pressures (as roller cams go) so the stress on the cam and valvetrain is reasonable. They seem to get a good life out of them.
Some purests turn their nose up at the cast core street roller cams, but I have yet to see one that failed in service, in the intended application. I have seen $400 billet cam cores snap in half, wear out the distributor gear, etc etc. If you are building for 8500rpm and 700+lbs spring pressure this is not the cam for you. If you are building a street strip motor that might see 6800rpm once in a while these work fine. Get the complete matching kit and install it correctly. http://www.summitracing.com/parts/CCA-K11-771-8/ Your stock cylinder heads will probabily need some machining to accomodate the high valve lift. This kit is very simular to the hyd cam you are looking at, but will perform much better. It is very simular to the one G-H runs. Designed by the same cam guru with the same purpose in mind. (hot street, prostreet, strip machine.) The one we installed recently was the next bigger duration in the series. Runs very well on the street. Definatly has the bad boy idle and gets up and hauls when you get on it. These cams can be custom ordered on a custom billet street roller core with the pressed on cast distributor gear on the back. Priced accordingly Call Comp Cams tech for advice if you want to go that route. I origionally speced out a simular Lunati/UD/Voodoo cam for my friend but he went for the lower price of the Comp complete street roller cam kit. Seems to be working very well. Last edited by F-BIRD'88; 07-26-2009 at 05:21 PM. |
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Check with Howard's Cams/Competition Products.
Shane |
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