TROUBLE MAKER

I was thinking about the Crane 168731... Would this be a good choice? Will the lift on this camshaft still work with the current stock lifters? And of course I'll be reworking the heads with the proper springs etc...

Thanks,
Gary

ROTAX454

Now there's a debatable subject. Really do need more info on the motor. Completely stock? If so, what changes/upgrades do you plan? Remember, it's all about combination. Especially with the cam. Ok Chris Straub or RMbuilder, chine (chime) in.

Pat McPherson

Yes, the 731 is the cam most people suggest.
No, you should not use the stock lifters. Some say you can, but they are on the edge.

TROUBLE MAKER

The motors will be bored to make 509's with flat top pistons, so the compression will be down just a bit over what I'm currently running. And, I'll probably do some head work to have the oval port heads matched up to the rectangular port intake manifolds that are currently installed. Will stick with the IMCO exhaust.

AIR TIME

Whats The Size # On The 731 L, C, D,

Smitty

I just installed the same cams in my motors and I used the stock lifters. They will work with no problems. They will not work with the 741 cam though.

cstraub

The heads on the ZZ's are not impressive flow numbers out of the box but with some work they respond real well. If you leave the heads stock these engines need about 12 degree split at advertised duration, an 8 degree split at .050" and need to be equal at .200" tappet height. Intake lift needs to be about .50" more then exhaust.

If ported a single pattern type cam will get you real close.

GM rates the chambers at 110cc. The last 2 sets that I dealt with were 114cc and 116 cc. Chamber size needs to be checked.

Donman

I have a "barely used" 731 roller that I will sell. It was in my Gen VI 454. It was ran 50 hours, in excellent condition. I used it with the stock lifters / COMP springs. I upgraded to a bigger cam recently.
PM or email me if interested. I`ll sell it for whatever fair market value is for a nice used 731. I paid $350 for it 18 months ago from Summit Racing.

Bubbletop409

AIRTIME Here are the specs for the 168731 Crane cam. I beleive it is offered in configurations to fit both the Mark IV & Mark V VI series engines. Intake lift .587, advertised duration 288, duration @ .050 226, opens 6 BTDC, closes 40 ABDC, max lift @ 107. Exhaust lift .610, advertised duration 296, duration @ .050 234, opens 54 BBDC, closes 0 ATDC , max lift at 117. These figures are based upon using a 1.7 to 1 rocker arm ratio which is standard.

TROUBLE MAKER

Thanks for the info guys...keep it coming...