ptroxx

No im planning on getting the rockers,and maybe the harden push rods,, seems a cheap price to pay to make sure im getting the 525 lift..
Am i missing anything else here... I may even do the elec fan set up whil ei have the front of the car apart.. been wanting them for a while....also doing the spreader bar up grade,, so its going to be an all in one mod cam,fans,intake,spreader bar....

LOL It just never ends...

jackson

the lt4 cam has about 10* more intake duration ... that has much more significance than thirty thousandths more lift.

decent 1.5 or 1.6 roller rockers in self-align ain't cheap. increased RAR will add to lt4 cam, at best, 1 maybe 2 more degrees duration and about 30-thou more lift.

it's your bolt-on power $budget ... if you're determined to get 30-thou more lift, suggest look on fleabay for another cam.

i.e.
http://cgi.ebay.com/ebaymotors/SBC-S...item27b738af62

http://cgi.ebay.com/ebaymotors/CUSTO...item518d93f228

ptroxx

Im sticking with the lt4.. and the 1.6 rockers at this point..
its a proven cam and lifter package.. Thanks..

Jason Staley

That reminds me, if you do not use self aligning rockers ($$$), you will need new guide plates and hardened pushrods. The "guide plates" originally on the ZZ4 were there for assembly purposes and are not heat treated properly to be used as push rod guides. They just use the typical SB guide plates that all the cam companies manufacture, not real expensive but worth the effort.

One more detail I changed was I went to ARP rocker studs to strengthen and stiffen the valve train. Probably wasn't necessary, but I like over kill.

ptroxx

OK so does anyone know how i can tell if I for sure have the correct cam.. ??? I purchased it from Craigslist..LOL I know..
I has the correct part # on the tube.. but can i make sure on the cam stamp some how.. ? ?

rad87gn

Hi Guys! I'm not a Corvette owner but I've been doing a ton of research on ZZ4 engines and this conversation here and many more I've seen here got my interest. Jason Staley was one that got my attention. Sorry to dig up a really old thread.

I just wanted to share what I got out of my ZZ4 in my '79 Hurst Olds with not much but a cam and valve spring swap. This engine has been in the car for 19 years and this is what I got today. Instead of the Hot Cam I went with the little larger one from GM which I believe is a Crane cam repackaged.
GM Roller cam (234/242 @ .050 duration .539/.558 lift)
https://www.summitracing.com/parts/nal-19244485

https://www.summitracing.com/parts/crn-109841/applications

Almost nobody on the internet that I've seen has swapped just this cam in and see what it can do. So thought I'd share. The cam is extremely streetable and I can get pretty good gas milage with it. From what I've heard from GM this cam did 397 hp/430 torque with their testing just doing the cam/valve spring swap. From my dyno session it seems to be fairly close to that flywheel. I think I have some more gains by installing the RPM air gap intake and a 750 double pumper Holley. Just some easy bolt ons without changing or unbolting/modding the heads. The stock distributor had the weights and springs replaced before the dyno session to come in faster and had vacuum advance plugged. Also installed the correct power valve to match the vacuum being only 11-12 with this cam. The jets in the carb are 72 in the front and 82 in the back.

With the stock intake it pulls to about 6,200. I'm sure it can do better with an air gap intake to match. Looking at the dyno and video of the car doing track runs I think I could use a higher stall convertor than what I have. Good 3,000-3,500 stall I think would be perfect. My lower stall is hurting my 60ft times. I have a lower stall because most of my steady cruise speeds are 3,000-3,500 on the highway/interstate and didn't want the convertor getting hot on long drives since the car is 99.99% street driven.

All specs are on the youtube video and comments. Let me know what you think. Next dyno session will be using a 125hp NOS nitrous kit. It drops 1 sec in the quarter exactly from my experience and works fine with 91 octane pump gas.