scotty230

receonlty put in a holley 650 dp on my streetported 12a and cant seam to get it running right. what jets should i put in it, i went and got the holley jet kit ( 64-90)
every jet i put in it the car bogs real bad, but if u ease into it and after about 4000 it pulls pretty good, as of now i have 64 primary and 70 secondary. Any help would be greatful, like today when i took it out, if i go out of first gear and step on the gas it just sputters and actually almost stalls , but if i ease into it , it goes like a ****** ******

FB II

you need a better ignition. also, what power valve are you running?

scotty230

i am running msd blaster 2 coils and i dont know about the power vavle i guess its the same one that ws in the carb when i btough it, the carb is brand new

FB II

well when i say you need a better ignition, i mean get an msd box to the leading atleast. on a holley like this, with the powervalve opening at probably 6.5hg, you are dumping massive amounts of fuel. it's probably dipping in the 10's atleast on the afr's. your stock igniton can not push thru that. one thing you can try, is jet down the secondaries to say... 66 and remove the secondary accel. pump arm. see how this does.

racintang

I had jetted down to a 64 primary and 66 secondary. Then get it running at warm idel take a vaccum pressure reading. You will see an hg reading on there. Take that number and that will be the power valve size you need.

mcnannay

i use a 2.5hg power valve on my 13b, idle was great

84stock

iTrader: (5)

too much fuel for sure! You can make soooo many more adjustments as well. I have to say the problem is with your accelerator pump. You need to make changes to the accel pump cams and shooters to fine tune some more.

FB II

what color cam you rockin? and i've had good luck with size 28 squirters on both sides.

scotty230

thanks for the imput guys but how do i tell what squirter i have

jim_chung

iTrader: (2)

If you give me the actual model number of your carb (should be stamped on the underside or on your invoice) I have the Holley catalog and can tell you your power valve and accelerator pump specs. I think you might need to invest in buying one of those Holley how to books because you are sure to get conflicting advice from people, lot cheaper than buying an entire jet kit!

82BUCKET

iTrader: (4)

I Had The 465 Kit On A Stockport12a With 49 Jets, And Also Got 51 And 52 For The Streetport Upgrade I Never Got Done But Was Told That Would Be Plenty And Not To Much By Rb.

13btnos

iTrader: (1)

I think the problems are with your carb to motor choice. A 650DP on a streetported 12A is way over carbed. If you had a bridgeport 12A and I'm talking a pretty decent size bridge than a 650DP would work for your setup. Already stated you need better ignition 2 MSD 6AL's would be great others have different setups. Is your intake ported like did the make it an open plenum on the top of the intake?

scotty230

yea the intake is ported , i plan on doing a nice bridgeport in the near future and the model # on the carb is
4150

13btnos

iTrader: (1)

Well if the intake is ported/open plenum I can almost bet that the power valve is blocked off. This is a common setup with drag racers and especially if you are going to add NOS to it. Almost every Puerto Rican drag racer I know does it this way. I do the same thing but I use the the Holley 600cfm carb intake plenum is opened 1/2in down from the top and then the the NOS plate itself is 1/2 in so total open plenum is 1in down from the baseplate of the carb. 12A I stay with 66's and on the 600cfm carbs there's no jets on the rear but there is a plate that I do some adjusments to. Still the problem is not with the carb but that the carb is to big for your motor. Streetport 12A cannot suck up a 650DP sorry but you can try all day long with different jets and it still won't run right. And with the intake plenum being opened up you will not have a good transition between the primary and secondaries. There will always be a stumble around 4000rpm's unless you just stomp on it and leave out of 1st gear as high as the motor can rev that's how that open plenum is setup for. Drag racing setup not good on the streets.

scotty230

thanks yea its like it dont want to run at low rpm if i stomp on it but if i ease into it its good to go

FB II

i have run a 600cfm double pumper on a stockport 12a, only problem was with the powervalve coming on too early. fixed that.

jim_chung

iTrader: (2)

They make 8 different Series 4150 carbs that flow 650 cfm, I need the model number which begins R4777 - 1 through 7 before I can tell you your specs, or you could just take your carb off and take it apart.

scotty230

how dose this do for model # 0-4777s is that sound right if now i will look on the side of the carb

custom13B

Scotty the carb is very oversized thats your main problem as 13btnos stated. Also a vacuume secondary would help you as well. I do remember the racing beat holley is 465 cfm for a street ported 12A and uses number 50 main jets and number 28 squirters with a black pump cam. Im sure you can find a used holley 390 cfm with vacuume secondaries. Maybe check ebay. You can press on with your current carb but in the long run you would be better off with a smaller one. Your driveability would be better with a 390cfm that a 650dp anyday on a 12a. The 465 RB sells in no longer made so thats why they get to charge a ton for one. Look for ther book Carburators and intake manifolds by David vizard in the local book store order it if needed its like 18.00 then you'll understand why and how to tune your holley. Good luck

scotty230

thanks custom13b but it sucks i just bough the 650 like a week ago

FB II

remove the powervalve and see how it acts.

scotty230

i found ou tthat it has a 6.5 powervalve and the squirters are 28 front and 32 rear do u thyink i should put in a 2.5 powervalve or just get the brass screw and block it all together

jim_chung

iTrader: (2)

If you remove the powervalve you will need to increase main jet considerably otherwise under load your carb will not deliver enough fuel (because there will be no powervalve to deliver it) When you're at cruising speed the large jets will make it impossible to run a good mixture, it will always be overly rich. You're main problem is the large cfm rating means that the vacuum secondaries will never open and if you rig it to open mechanically it will screw up the vacuum signal and wreck your mixture. The whole idea of the 4 bbl Holley system is to provide good fuel efficiency in town by just using half the capacity and when you need WOT extra capacity is available in the secondaries.

FB II

swap the squirters. put the 32 in front and the 28 in the rear. you can try a 2.5 pv, that will pretty much set it to where it only opens under WOT. if you decide to try without it, then jet up each side 6 sizes and start from there. it's not as bad as chung describes. it's the same as modding your stock nikki for high performance applications (what i had to do). i cruise at an afr of 12:1 but with my beast ignition... it doesnt matter.

smurfy RX3

Jim chung is right, if the secondaries are vacuum operated don't try to make them operate by rigging the carb. I used to get the same bog w/ my vacuum secondary 4150 unitl I installed this part: Summit Performance Part# QFT-63-1. This made a HUGE difference, you'll be able to adjust the secondariesw/ just a screwdriver. Remember that the vacuum secondaries will only open when the engine is under load, they'll never open just sitting in your driveway even if you go to WOT.