holley carb guru
 

Looking for a real good holley carb guru to send out my 2- 500hp carbs for a fresh up.

Still Looking

No guru needed......... I can do them in my sleep.

I use Dean Nickerson in Bristol, PA. but these were more than just rebuild, he did a stage 5 mod. removed and blended the air horn (choke tower) and other internal mods to go improve flow.

http://nickersonperformance.com/

Some on this site will voice displeasure, however, I have had only one issue with one of his carbs. The accelerator pump diaphragm failed after 4 years, but that was hardly his fault. Also, jetting was perfect, Same plugs for 4 years looked perfect when I replaced them, tan just like my women.

Since im in pa also that sounds good.

if its just a freshen up, they are really simple to do yourself.

Yea ive done them before on race cars,, just have no heat in my garage where the boat is and would like to just pull them off and send them out as it cant cost that much because they are easy as you said.
Thanks

What are they doing that you think they need rebuilt?

Still work good but one motor was stalling when put into gear and both load up when ideling and they havent been touched in 10 years since new. I have powered up my hp 500s to around 600hp and a crane 741 cam so they may need a little more jet as well.

Sounds like your power valves may be leaking. Have you ran it with the 600 hp yet? If you have I would look at the spark plugs and see what they look like but if the power valves are leaking you would have to shut down after a run and pull a spark plug right away with no idle time.

Probably need to fine tune the idle circuit/mixture screws, and blow out the air bleeds with a can of carb clean. Something you will need to know how to do, even if you send it out and put it back on after a rebuild.

One thing alot of guys do is crank up the idle speed screws. What ends up happening is the throttle plates open too far, and the carb begins bypassing the idle circuit. Ends up running like crap, loading up, etc.

A vacuum gauge is a useful tool to tune the idle mixture screws. But, you can do it without one. First i would blow out the air bleeds, both idle and main jet bleeds. i'd turn the idle mixture screws all the way in, and then back them out 1.5 turns each. Start the engine, let it get warm. Then take each screw, and slowly turn it in until the idle speed drops. Then back out a 1/4 turn.

If you find turning the idle mixture screws in all the way, doesnt wanna kill the motor, the idle speed screws are probably turning up to high, which you will need to back them off, and re-adjust everything.

Once you get all that sorted out, you can go do some WOT runs, and check jetting. I believe the 500HP engines used staggard jetting. They ran on the fat side stock i believe. So you might be ok with the upgrades, but I'd still check plugs.

I have 540 hp 502s that have a little more cam and cnc dart pro one heads. I use 800 cfm holleys jetted the same as an HP500.

Staggered jets Pri 81/75 Sec 89/93. It takes a little time to tune for good idle, but it can be done as thunder explained. You may have to adjust timing at idle as you adjust idle.

End result will be better idle, but will still run a little fat at speed.

Thanks Guys that was alot of help and good info.

stagered jets
 

Sport...Can you explain "staggered jets Pri 81/75 Sec 89/93."? Thanks

What he means is merc used different jets all the way around in the HP500 carb. Most common jetting would be say 92's in the primary, 96's in the secondary. Where as merc didnt use the same jet size in the primary or secondary on the HP500 setup. The primary got a 81 jet and a 75 jet, secondary a 89 jet and 93 jet.