Since I am re-building the motor, I have searched for information on the Hot-Cam kit to upgrade the ZZ4 a bit. I've found some confusing information, so I am asking this: Can you just upgrade the cam without also doing the roller rockers and fast-burn heads? I've read that the stock ZZ4 heads have the correct valve springs/retainers etc already on them, so it's cheaper to not buy the kit but to buy the cam and rockers separately. I'd like to if possible do the cam now since the motor will be apart, and let my son change the heads and rockers later to effectively have a ZZ430. Any ideas?

Yes, you can run the hot cam as is in your motor. Double check to make sure the valve spring is the correct one - I believe it is. It gives you valve lift in the .495 range with the 1.5 rocker arms as opposed to .525 with the 1.6 rockers. You can also re-use your hydraulic roller lifters if they are in good shape. As far as price goes, it seems to me buying the cam and the rockers separately is only a few dollars cheaper than buying the kit. If your motor is a high mileage unit, you might consider new springs as well.

Edit - Oops, I just realized your are the poor soul with the cracked ZZ4 block. (Moment of silence, please) In which case as I recall it only had 20 or so miles on it, so re-use your heads as they are.

The cam gear locating pin on the hot cam should be driven in so that it is flush with the face of the gear for your ZZ4.(Compare it to the pin on the cam you're replacing .I tapped mine with a small hammer) I think the long pin was for the cam driven water pump on the LT4.

PS The GMPP roller rockers will fit under the stamped steel center bolt valve covers that came with the engine.

PPS I sold my original low mileage ZZ4 cam and rockers for $80 on e-bay in about 20 minutes!

[ 02-26-2003, 01:17 PM: Message edited by: BPOS ]

BPOS's advise is right on.
I installed the complete Hot Cam kit last year in my ZZ4 short block. The cam comes with directions on how to deal with the timing gear pin.

67killerb, I've done the same thing you're talking about.

In addition to the great info posted by BPOS, I'd just like to say you'll like the upgrades.

You must use the GM 1.6 roller rockers, the HOT cam was designed for them. Sure the 1.5's would work, but to get the full benefit, use the 1.6's for sure. They are made for GM by Crane.

I also started with the ZZ4 and drove it about 400 miles with the 355 HP, 405 TQ. It was fun, but the HOT/1.6 made a huge difference. (GM says 30 HP).

Then the next year I did the fastburn heads, and the Edelbrock RPM Air-Gap Vortec manifold..... :D :D ....that's when life got real good! :cool:

I would just add, check the cam endplay after installing the front retainer, make sure it spins freely.

Thanks! You've answered all my questions, and I am encouraged that it did make a difference! Thanks again.

i would get the kit, if only because it is a smoking deal for all the extra stuff you get. i'm sure you could sell off the retainers and springs for a few bucks, and the cam is designed for the 1.6 rockers that come with the kit. i have the HOT cam kit in my nova (well, in the engine that goes in the Nova- if the car ever gets back together), and i simply love it. smooth idle, 15 mpg, good power from idle to 7000. i would think that by not getting the kit with the rockers, and giving up that lift, it might be a little weaker at the top of the rpm band, but should still perform well everywhere else. guess that makes the choice a little bit tougher, and your financial situation will be the final determining factor.

Well, at lunch today, I went down to the dealer and ordered the block and the hot cam kit, so I've got about a week to tear the old motor apart and get ready to put the new one back together.