I bough a holley 650cfm double pumper for my new engine that is pretty much done. The only thing im worried about is that it has mechanical secondaries. Someone pointed it out earlier in an earlier post that i made a while back. I just started to think about it, and do some research and it seems that mechanical secondaries are for cars with either a manual trans, high stall, gears over 3.73s, or cars under 3500lbs. My car dosnt meet any of those requirements. My question is what can i expect from the carb? Will it be fine if i learn how to drive it, and "roll" into the throttle instead of mashing it, or is it hopeless and should i trade it, or sell it and get a vac secondaries carb?
My uncle has a brand new Q-jet and he is willing to trade carbs with me, i really dont want to do this because i really like the holley, but if its in the cars best interest then it would be stupid not to do it.
Is there any conversion kits that i could make it a vac secondaries carb?

here is the car info
1986 berlinetta with a rebuilt 350
comp cams 262xe cam pocket ported heads that are cut for slightly larger intake valves, and an edelbrock performer eps intake. Stock torque converter, and stock gears (2.73s).

 

Roll into the throttle, don't open the secondaries until you're up in the rpm range quite a bit. I would have ditched the stock converter for a stock s10 converter while the motor is out and get a 2200 stall at least that would be a cheap improvement. Also no reason not to swap out the rear for another stock rear with 3.42s or larger gearing later down the road.

 

I guess i could have tried harder to find a torque converter, but i was kinda getting overwhelmed with everything the engine needed. I just wanted to get it together and running. My next project is a posi and gears, so hopefully that
will help the situation. If you had to guess what rpm to open the secondaries where would it be? 3500-4000?

 

holley has a chart on their website that shows what rpm for the double pumper to have them opened. I would look into that S10 converter since it's under $150 and retains lockup though. Don't buy posi and gears then pay to have them installed, just buy a rear off someone with the gears/posi that you want instead of blowing $800 on the rear you have now. 4th gen rears are also plentiful and are getting cheaper and cheaper.

 

do 4th gen rears bolt right up? i could probably do some research and find out for myself if you dont feel like going into detail. I wouldnt pay to have anything installed, i would do it myself. Where can i find rear ends? look in the paper? junkyards? online?

 

http://www.holley.com/data/TechServi...Carburetor.pdf

A 650 DP on a 350 can go WOT at around 1300 RPMs. You won't have a problem with the carb. You'd want more stall for the cam, though.
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Bolt up? Yes.

Work? No. They're wider, so you need more backspacing for the rear wheels. since they're otherwise no different from 3rd gen rears, there's really no reason to go through that pain.

 

k, good to hear that the carb wont be a problem. So you're saying that i should not get a 4th gen rear? or i shouldn't go through the trouble of putting a posi and gears into mine?

 

Don't look for a 4th gen rear because it's 4th gen. If you find one with a posi and the gears you like, buying wheels to fit may be cheaper than putting posi and gears in your existing rear.

On the other hand, it'll probably be cheaper to put posi and gears in your current rear (and I would support putting posi and gears in your car).

 

3rd gen rear ends are still easy to find and you dont have to change back spacing or any other crap. Yes search junk yards, bargin corner of your local news paper, online ect ect. You might just be able to find a cracked up z28 or trans am for cheap take the parts you want off it and then scrap the rest at the junk yard. Anyway you look at it just go with a 3rd gen rear and save yourself a head ache. I got a 373:1 posi from the bone yard in Michigan for $150 and it made such a big difference! I would keep your carb...get a posi with 373's and another converter as other members already stated, you will have a big smile on your face the first time ya mash the gas pedal

 

My uncle has a posi that he will sell me, or give to me. I will probably just buy gears for it, like 3.23s or something, its gonna see kind of alot of highway driving so i dont wanna go too high on the gears. All this is probably going to have to wait though, im not going to have any money because of school.

 

that dp will most likely idle rich and need some mods to the idle circuit like the rest of the holley dp line of carbs when used on the street. They are setup for alot more camshaft than you have. basically your mixture screws will be around a 1/2 turn out at best to be as lean as you can get it and run with any type of fuel economy. The mixture screws work best at 1 to 1/1/2 turns out. I drilled my idle air bleeds significantly larger and it worked out very well. I have a 750 dp but what i have been reading lately is they are all similar.

 

i have a brand new 2000 rpm stall converter with lockup from monster transmission for sale, 150? make me an offer if you want it.