[highwayphoto]

Well I have been running my zzz motor for 20 years.I have not been to happy with the performance for some time. The motor is making an odd sound so its time to tear down.my question is what cam may be better than the original?
for my street use 0 to 70--- quick. I actually purchased the motor after the photo shoot in Oct of 1989.The PIN# for the original cam is 10134334.
is the new ZZ4 cam a good replacement? It seams to me my motor is made for Dirt track running (constant high RPM's) I just want some respect from the local tuners from 0 to 60
Any Ideas?
Kent

[backardracer]

comp cam has a new line called tumper or somethin like that my buddy just put one in hes 81 z28 camaro sounds great preforms well it would better with a bit of a stall i think it like 279 in 297 ex 479lift in 465lift ex sounds great
runs good

[ap72]

No one likes the performance of the Thumper line of cams because frankly it has WAY too much exhaust duration for almost any NA set up. And too tight of an LSA for any boosted engine.

If you're going for a complete rebuild then a lot of parameters besides the cam can change. My advice would be to run a hyd. roller if you can afford it, or a proven reliable cam from a botique shop (I also like Isky even though they're a little bigger). These guys will usually have the know how and intellegence to help you out, even though they may lack a "tech line" or a marketing staff. That being said the 264Mega is one of my favorites for low/mid range power, but for about $40 more you can get a cam matched exactly to your combo and sold to you directly from the guy that makes it.

If you have a very limited budget I know of a few cheaper box stock grinds, but to do it right you should spend a little more and get it done by a pro. They can also recomend target compression ratio, intakes, etc. to you- usually for free as long as you buy their cam.

[techinspector1]

At 9.0:1, you need less cam, not more. The ZZZ cam (10134334) is spec'd as follows:
235/235, 480/480, 114 LSA.
The 10185071 ZZ4 cam is spec'd as follows:
208/221, 474/474, 112 LSA.

The ZZ4 cam, in my opinion, is the one to use if you want to stay with a GM cam. It is perfectly matched to the 9.0:1 static compression ratio of your ZZZ motor. Of course, uncorking the motor top and bottom with a dual-plane, high-rise intake such as an RPM or Stealth and long-tube, equal-length headers would go a long way toward helping hp and torque. This assumes, of course, that you're using a carburetor on the ole 'Vette.

At 9.0 and 235, I can see where the cam would be a little soggy on the bottom and peaky higher up.

[F-BIRD'88]

Replace it with GMPP "LT-4 Hot Cam" 218-228-@.050" 112LSA .525"-.525" lift
w 1.6 rockers .492" .492" w 1.5 rockers. The valves springs will need to be upgraded as well. You will have lot more overall power and torque including better low end grunt.
Cylinder head retainer to guide seal clearance at full lift with .525" lift needs to be checked. The guide boss es may need to be machined shorter for the increased .525" valve lift if you use 1.6 rockers.

If your hyd roller lifters are still good you can reuse them on the new cam.
The cylinder heads on that motor really really really respond to a good hand porting. Combine the two upgrades and it will feel and go like a whole different motor.
Does that "ZZZ" motor have a dished piston or a flat top piston?
Rebuild with flat top pistons. w 1.56" compression height.
That motor should have a good Forged crankshaft in it.

[backardracer]

now there is ppl out there that like the thumpr cam i do and my buddy we do run higher compresson about 10.5:1 with old school duble pumper holly and e85 it works well in that setup maybe not so well on a lower comp motor but is was just my 2 cents

[ap72]

Originally Posted by backardracer

now there is ppl out there that like the thumpr cam i do and my buddy we do run higher compresson about 10.5:1 with old school duble pumper holly and e85 it works well in that setup maybe not so well on a lower comp motor but is was just my 2 cents

Have you tried to compare it to a cam that was ground by a profesional? Going to a real cam artist would give you a difference in hp and tq that I don't think you realize. I'm not saying stepping up to a solid roller or anything either, just a more appropriate cam.

[backardracer]

no i have never had one custom ground and yes i'm sure it would put out a few more hp and or more torq but i'm sure it would cost a lot more to have one ground but the thumpr is not as bad as your making it out to be and it might not be the cam he is looking for but i just threw it out as another choice

[ap72]

Its not as much more as you may think it is. In some cases it may even be less. In most cases its about $40 more though. $40 for 30ftlb more torque and 20 more hp seems like the bargain of the century.

[sandiegopaul]

Originally Posted by highwayphoto

Well I have been running my zzz motor for 20 years.I have not been to happy with the performance for some time. The motor is making an odd sound so its time to tear down.my question is what cam may be better than the original?
for my street use 0 to 70--- quick. I actually purchased the motor after the photo shoot in Oct of 1989.The PIN# for the original cam is 10134334.
is the new ZZ4 cam a good replacement? It seams to me my motor is made for Dirt track running (constant high RPM's) I just want some respect from the local tuners from 0 to 60
Any Ideas?
Kent

Use the GM 962 cam ... it's good idle and high RPM performance should fill the bill.