My car was down for 2 months, and working at a turtle's pace, I was cutting it close by completely finishing it last night. Made it to the track today and made it home before the Broncos played! I haven't touched my motor in 4 years and last time was when the 502 went in. I've been planning this out for a long time and I'm happy with the results.

I got the heads off and all my exhaust valves were bent. Got a valve job, shaved the heads and gasket matched. Also went to the stock dual plane intake vs air gap intake. I had a custom design solid roller by Christ Straub and the heads were worked on at a local shop. She is definetely liking the set up! I went from 12.43 best to 11.91!!! My mph jumped from 106-112!

I haven't tuned it yet, but i think i can get it in the low 11.80s. This thing still runs on 91 octane and only let 7# of air out the rear tires to race. 60's were in the 1.66-1.7 and i am going to try to work on them.

Its been a long time coming but this new cam is a different animal compared to the tractor cam that comes stock on the zz502. I don't know if I'll make it to any more races this year but if theres a track day next year, then I'll hopefully get it in tune!

Thanks go out to Chris Straub, Mike @ USA PERFORMANCE, Tony @ ON TRACK, and my dad, rick, mike, lyle

Rob

What are the specs of the old cam vs the new?

Has anyone noticed how the GMPP crate motors all have small cams or crabby cams?

CONGRATS and what gears are you running?

Why the intake swap? I'd think the airgap would work better with the larger cam?

stock is 224/236 thats off top of my head. Running with 4.10 gears and crossing the traps around 6100 right now.

Air Gap intake had huge port mis match and size differential compared to the ports on the head. The intake port is .25" bigger in some places and .125" smaller in others. The stock intake is oval ports and matched to the heads much better. I also have a 1" super sucker spacer on there and a only holley 750 dp.

Is this on street tires? My stock zz502 pushes my car 11.8 in the 1/4 mile, but with slicks.

ET Street Radials. I'm up a mile high so i dunno if lorain, ohio is up that high.

Oops. I didn't even take that into account. :clonk:

Going to send you a pm with a couple questions.

The stock cam is 224/234, .527/.544, 110LSA (guessing 108ICL). Running the same heads on my 460CI motor with .600/.610 lift. These heads work well into the .600+ lift range.

Regarding the AirGap intake, I used the "off shore" brand air gap and had very little (to none) port work to make it fit-up perfect. My Ede Perf 2-O that was onthe oval port 402 motor needed major work to get it even close. It was not the size of the ports that was a problem, the port size/shape was fine, it looked as though it had core shift during the casting process and was off by a little over 1/8" on both sides one side was cast high, the other was cast low.

Glad you got things worked out. Give us all the updated cam/spring specs.

Rob,
Your quite welcome. It was great to work with you on the project. Please note on Rob's cam specs I compensated for his altitude in the duration and lift specs. How is the throttle response Rob? Where does the torque seem to come in at?

Chris

the new cam is 256/260 @ .680/.720 lift @ 108 (somewhere around there, can't find the card now). Springs are the manley NexTek series polished manley 221442-16. Basically circle track rollers w max valve lift .750, OD 1.56 ID .812, Installed pressue 260 @ 2.000 and 660 @ 1.250.

Chris: The throttle response is amazing. This cam feels like it lost no low end power and where my old cam used to stop it still pulls an extra 4-500 rpms. I used to shift at 5400 and yesterday by feel I was shifting around 5800/5900. Going through the traps at 6100 rpms, but by no means was this engine running out of steam, it was pulling hard all throughout the 1320! Before I would be shifting it and "cruising" cuz the cam wasn't really pulling much after the 1/8. The torque seems to come in right away, I was launching off idle and still getting incredible launches. The most improvement I noticed was the cam keeps pulling and making the car go and it really winds it up quickley!

Thanks again for your help Chris. I would be happy to reccomend your services to anyone and it was a pleasure to work with you with all my issues :D

Rob,
Sounds good and you are welcome. IMO throttle response is important. How quickly an engine can recover and reach its powerband after a gear change equates to FAST. Sounds like we have done this especiall since you are foot braking this combo with a stock converter.

Just a note on the cam specs, Rob is at 5000 ft plus in elevation so the lift and the duration are compensating for this. A zz502 closer to sea level will not need as much to make the same power as Rob's.

Thanks,
Chris