98itrwhite

i did a search and i cant really seam to find a answer. hear alot about the crane 721 cam but cant seam to find it on there web site. i would like to use it on markIV 330 motor with merlin ovals. any help would be great thanks.

axapowell

Crane Part number 168721...Here's the link:


http://www.cranecams.com/?show=brows...21&lvl=2&prt=5

98itrwhite

in the discription it says for 1996+ will that work on a markIV motor from a 1990 baja?

Bubbletop409

I think the cam snout on the Mark IV is different from the Gen V & VI. All the rest is the same. I think they make the same grind for the Mark IV 's under a different part number, but do not have it, try their tech line.

axapowell

Sorry...didn't see the year.
Tech Hours
8am - 7pm Mon.- Thurs.
8am - 5pm Fri. EST

Tech Line - 386-258-6174

38KV

The Mark IV version is 139721, or actually was.

The part# is changed from 139721 to 139001.

98itrwhite

thats the one thanks alot for the help. 1 other ? i have is that should be good all around cam for my 454 right? i am runing a 330hp 454 with merlin ovals with porting,port matched dart high rise intake and a holly 800cfm. i am going to be using dana marine flo torqe manifolds with dana tube risers. not reving over 5k due to cast internals. i am just trying to get all of my ducks in line for the spring, so i will take any help i can get. thanks

formula31

That must be a roller cam. Look at the recommended spring pressures, they would eat a flat tappet cam. Do you have a roller cam in the engine now?

Whiteknuckle

formula31,
I agree, that has to be a roller cam. He is going to spend a lot of money to put a roller in that engine. I'm not sure the pay off is there. He may want to stay with a flat tappet and spend some of that money he saves for pistons, and better rod and main bolts.

rmbuilder

If the engine still has the stock cam it is a Hyd flat tappet.
GM part #3904359
278*/289* @ .006"
213*/217* @ .050"
.460"/.480" Lift valve
114* LSA

The Crane 139001 is the Z series Hyd- roller. The change over would include:
lifters
cam button
check pushrod length
springs/retainers/locks (depending on what hardware you have with the Merlins)
Bob