Holley Carburetors: Accelerator Pump Tuning with Pump Cams

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Accelerator pump cam list by color
Black lightest/least aggressive
Pink
White
Red
Green
Orange
Blue
Brown
Yellow heaviest/most aggressive

[@dualdrive3628]

Thanks!

[@holleycarbshowtosadvice40y90]

Thank you.

[@jamesruscio6536]

I appreciate your video instruction and that you listed all the cam colors in sequence of aggressiveness. I have a Holley catalog that shows each cam on a graph but you were more concise and clear about it. Thank you.

[@holleycarbshowtosadvice40y90]

Very welcome

[@StephenGiovi]

Thanks for all your help with these tuning tips. My engine is running a lot better now.

[@holleycarbshowtosadvice40y90]

Very welcome

[@CHILLINWITHJPAX]

Your vid’s have been a HUGE help as a beginner working on my GMC 5.7 V6 replacing a Holley 350cfm 2 barrel!!! I have followed your advise and it’s running really good. Just working on why it surges when driving at low speeds and light throttle. Keep up the videos!!!

[@holleycarbshowtosadvice40y90]

Thank you and let me know if I can help.

[@butchking154]

glad to see ya back randy greatvidio

[@holleycarbshowtosadvice40y90]

Thanks

[@UpVoltageOverclocking]

Love your vids!! Can’t wait for part 2 of automatic choke!!

[@holleycarbshowtosadvice40y90]

Thanks , part 2 coming soon

[@garhpd]

Awesome explanation! Makes 100% sense

[@holleycarbshowtosadvice40y90]

Thanks

[@nathanbishop3814]

Randy! Big fan over in AUS here 😎 Would love to hear your opinions on mounting angle for holley carbs, especially if you think its important. Ive been struggling to find a cure for years as to why my BLP 500 is so sensitive to angle... Braking and even facing down a steep hill will make it lean out all the way and stall! My only work around is a super fat idle mixture so far

[@holleycarbshowtosadvice40y90]

Have you tried a different carb, and this happens just braking or driving down a hill. Nathan give me all the information you can on your motor and how much vacuum you have at idle, and is it worse with the engine hot.

[@braddenning1617]

I have two Holley 450s On a 60 over 292 inline 6 ,4 speed car 12.1 comp. 550 lift choppy cam, very hot street strip, 256 1st / 430 REAR. I have an off idol stumble ,DUI race dist, locked at 38 . Under 2000rpms It stumbles. If you heat up the tires ,wind up the RPMS and dump the clutch ,The car Hits hard then falls on its face. then you have to peddle the throttle to get it going .

[@holleycarbshowtosadvice40y90]

First check your fuel bowls for water and then I need your carb list number and your carb specs jetting everything .

[@happymotoring4674]

What size would you recomend for a 502 chevy with a mild cam and auto trans. It's in a 1 ton truck....thanks.

[@holleycarbshowtosadvice40y90]

Holley 750 list# 3310 street and performance 850.

[@solowkaver3592]

Can you do a video on replacing the teflon strips on the throttle shafts to take care of worn base plates etc. I assume there is an art to that and limits on what works and doesn't work. Thanks!

[@holleycarbshowtosadvice40y90]

The plates have to be rebushed the Teflon strips won't fix a worn out housing and shafts I've tryed it. Haven't checked lately but ebay was selling new billet plates for 100 dollars. Hope this helps.

[@solowkaver3592]

@@holleycarbshowtosadvice40y90 Thanks for the advice. AllState carbs sells base plates for a bit over $100 too. I may grab one of those.

[@meep2059]

Hi, i have a 3500 pound Dodge car with a 383 engine and a smaller cam, automatic 2500 stall converter and 2.92 freeway gears with a holley 3310 750 carb. vacuum secondaries. Can you suggest what color cam and what size jets for primaries and secondaries i should go with please? Thank you!

[@holleycarbshowtosadvice40y90]

I like the pink pump cam for its long duration, the pump squirter 035 , as far as jetting I don't know where your located but if your at sea level 72 are good sometimes 74 make a little more driver friendly, if your camshaft is small 6.5 pv will work fine, if you have a stock jet plate 134-21 that is a little lean its equivalent to .075 jet , but should work fine. Hope this helps.

[@b-17wingman37]

I have a 4180 on a 70`s era 460 cid . I want to go to a non emissions carb. Can you recommend what to get ? 4150 or 4160 ? Also can I go from the 600cfm to a 650 cfm and not use more fuel .

[@holleycarbshowtosadvice40y90]

Well running a double pumper definitely won't help fuel mileage so if its an auto trans and the engine is stock, probably would run an 1850 or maybe a brawler if you won't some adjustability the brawler 650 cfm vacuum secondaries and has screw in air bleeds, or if your like me maybe modify the 1850 an save the money. Take care.

[@elm7666]

Hi Randy, on my 4150 base plate it has plugs in the channel between the front and rear. It looks like the base in your video. It appears that your base has JB weld in the channel where the plugs were originally. My question is this. If I leave the plugs there, will it affect the four corner idle circuit? Should I remove the plugs if I want to have four corner idle? With the base I have now and the plugs still in, there is no adjustment on the rear metering plate idle screws. Thanks.

[@holleycarbshowtosadvice40y90]

Yes the idle track has to be blocked to make the idle mixture screws independent of each other, from holley they have solid pins pressed into the plate, if im coverting to a four circuit then I epoxy the middle of the track , next you need to set your primary idle transfer slots correctly like my last video. You may need to lean the idle circuit with larger idle air bleeds primary and secondaries. I would change out the air bleeds .003 at a time and should not need more than .006. This is if everything else is correct. Hope this helps.

[@elm7666]

@@holleycarbshowtosadvice40y90 Thank You!

[@mikecondoluci53]

im building a small block tunnel ram motor with .780 intake lift i built 2 600 holleys and i did the 650 base plates what color do you recomend to start with on dyno day

[@holleycarbshowtosadvice40y90]

Mike I would start with the red cam and tune from there, maybe .030 to .035 on the nozzle and again tune from there and lock the distributor advance out to all mechanical advance if possible or as much initial as I could get. and bring your jets may need to rejet up. Good luck to you. Good luck

[@mikecondoluci53]

ok thank you

[@crockpotracing6489]

randy i have a nice running s10 with a 383,750 holley in it. it has pink cams in it. is it worth trying a different one to see if i would benefit in the hit.i feel it has more in the 60' but i am footbreaking it too

[@holleycarbshowtosadvice40y90]

I personally like the pink pump cams, but I was always racing my nova at the track so I would set my carb a little fat on the launch and lean it up some on topend. Ps. Never hurts to try something different. Have a good day.

[@crockpotracing6489]

thank you sir.i appreciate you and love your videos

[@holleycarbshowtosadvice40y90]

Thank you.

[@jimmymarlen6058]

Can you do a video of how to set up a secondary on a double pumper? And how to determine what cam to use thanks

[@holleycarbshowtosadvice40y90]

Yes I can, this weekend.

[@jimmymarlen6058]

@holleycarbshowtosadvice40y90 thanks I appreciate that !

[@holleycarbshowtosadvice40y90]

Ran out of time this past weekend to do video but I'll have it this weekend, sorry.

[@Adamk-kv3es]

I have a 383 stroker in a third gen Camaro. When going to wide open under 2500 rpm it has a slight bog. I’m now at squirter 40 front and back. I was wondering if this is now too much for the car as air fuel reads high 10’s. Should I go back to 38 see if it improves and just mess with the pump cams?

[@holleycarbshowtosadvice40y90]

Ok when it bogs is your afr rich or lean and is the bog under light throttle or hard throttle, tell me about your engine, your carb list number, jetting, power valve, pump cam color, distributor timing, how big cam. I'll get back to you.

[@Adamk-kv3es]

@@holleycarbshowtosadvice40y90 Fixed my issue! Way to big of a squirter. I found it liked 35-35 with both pump cams in second position. At first I dropped to 37 and it took of like a bat out of hell but still had very slight bog. So I switched pump cam positions and it got better. Went down to 35-35 and boy it screams now!

[@holleycarbshowtosadvice40y90]

Glad your fixed.

[@steveduleck5125]

Howdy, If you don't have access to a 450 tunnel ram carb, Can you do a video using the 1850 carb for the tunnel ram? Thanks Steve

[@holleycarbshowtosadvice40y90]

I can do a video but there not the same carb the 9776 has mechanical secondaries with no accelerator pump in the rear?

[@steveduleck5125]

Yeah thats right, When I go bigger on my engine I will try a couple of 600's I have and I'll want to know how to set them up. Thanks Randy.@@holleycarbshowtosadvice40y90

[@holleycarbshowtosadvice40y90]

Just let me know i have 1850 600cfm.

[@steveduleck5125]

Yes please That would be great.@@holleycarbshowtosadvice40y90

[@richardmoreno3038]

Thanks!

[@holleycarbshowtosadvice40y90]

Thanks Richard.

[@dualdrive3628]

Thanks!

[@holleycarbshowtosadvice40y90]

Thank you