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Converting 502 to a carb need help

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Old 10-30-2017 | 12:37 AM
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Originally Posted by niteridder64
Midwest, did you see any gain and performance when switching to the carb.
Not really just got away from spending money and time with the mefi1 system , carb is easier to tune when other parts are upgraded at least for me
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Old 10-30-2017 | 01:40 AM
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Originally Posted by hallj
Griff have you run one of those in a low compression 502?

168761 might fair a little better. Either way break out the $$$$$ for some long travel lifters!!

Jeff
The cam you listed is just a stock 500efi cam.
I have run the 168731(very similar) in a 454/525SC which is 7.5 CR static and it worked well. I'd go one size bigger for a performance 502.
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Old 10-30-2017 | 05:49 AM
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The melonized gears are all over ebay. 2 questions. Which dia goes with which distributor. And since the ZZ and HO cams are steel cores, what about the other factory GM cams-distributor gears? Since GM got tired of wiped cam lobes, wouldn't ALL of their cams be steel, therefore all distrib gears hardened?
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Old 10-30-2017 | 07:37 AM
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Originally Posted by niteridder64
Thanks Jeff for all the words of wisdom sorry I had to ask again about where to find the gear I remember reading that post but I've read so much lately I didn't remember that it was actually in my post. Now you got me thinking this might not be so easy with some of the other sensors like the idle air control and TPS not hooked up it might affect how it runs the ignition .I will definitely have to do some research on this so if anybody out there has any ideas on the specifics of this kind of modification please dievulge any information.
I've done this with a GM truck ECU and it seemed to work well. Verified timing with the scanner and timing light. No IAC or TPS hooked up. No Codes.

Jeff
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Old 10-30-2017 | 10:49 AM
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Sounds like a plan I just remove my old gear and it Mike's out to 17/64. I'm going to stick with this zz 502 cam since it is probably already installed in the engine and my head builder has already set up the springs for that cam ,maybe I should've done some homework earlier. I will post updates or ask questions as they become relevant thank you everybody for the help.
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Old 10-30-2017 | 02:28 PM
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I have the ZZ502 cam also and have been happy with the DUI ignition, although I never switched out the gear so I’ll look into that. I plan on switching to a 731 cam this winter though just to step away from the reversion issues, and should be similar enough to use the existing valve train.

One note with the DUI ignition is that you need a dedicated minimum 12g power source. I ran a new 12g wire instead of using the EFI harness and the change in performance was stupid different. You will also have to rewire the tether kill switch too to cut the ignition.
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Old 10-30-2017 | 05:59 PM
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Thanks
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Old 11-05-2017 | 01:20 PM
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I have done this as well, DUI dist are nice pieces, I have had great success using the H/P HEI's from summit, I get the vac advance eliminator and use the petronix rev limiter, used the gear that came with the dist on both the std cam and as well when swapped in a 500HP cam... if you go with came change go with a single plan intake
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Old 11-05-2017 | 08:33 PM
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Originally Posted by dereknkathy
The melonized gears are all over ebay. 2 questions. Which dia goes with which distributor. And since the ZZ and HO cams are steel cores, what about the other factory GM cams-distributor gears? Since GM got tired of wiped cam lobes, wouldn't ALL of their cams be steel, therefore all distrib gears hardened?
i am a little leary about those from ebay,i buy them from summit.
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Old 11-05-2017 | 09:08 PM
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Summit racing equipment in Ohio. Pretty sure there is s .491 Dia and .500 Diameter. Mine are .491. Push the pin out and measure shaft with caliper. If you don' have caliper, go to someplace like autozone. They have them under counter. Or just buy a cheap set. Mallory, msd, ECT. You will have to make sure you have proper clearance between housing wear plate and gear face. .010 is good. My gear was tight against housing, you have assemble measure with feeler gage then take material off of gear face until it's right . Most gears will be tight against housing wear plate. Just call summit hit 2 for help questions wih parts

Last edited by veloc410; 11-05-2017 at 09:14 PM.
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