i keep reading that a vacume secondary carb is a no no. but i i were to block off the vacume port running the secondaries and put a screw in the linkage to make the secondaries open with the primaries would that work? if not why not?

_________________
1966 Plymouth Valiant, 225, 3 on the tree, 8 1/4 3.21 sure grip, hyperpac, holley 650dp, holset h1c

You need to read the section of Dave Emmanuel's Holley book on Modifying for Turbocharging. It explains the mods for draw through and blow through apps. There are companies that should have the linkage you need to make that mod, homemade linkages can bind up and not give good results...Also it might just be cheaper to get a 600 cfm mech linkage carb off craigslist to boost through than the hassles of converting a vacc. secondary carb...

-D.Idiot

i was planning on getting the dp but was curious about he vac secondary carb because i have a dozen of them laying around

_________________
1966 Plymouth Valiant, 225, 3 on the tree, 8 1/4 3.21 sure grip, hyperpac, holley 650dp, holset h1c

with a blow throw you have no were to get a vac signal, everything is on the pressure side. with the vac secondaries you have no pump shot to over come the idle circuit to main system flow starting point even with a pressurized intake charge(bog).

He already knows this, but is inquiring if there is a way to make a vacc. secondary carb a mechanical secondary carb. I know that a secondary idle system can be done with the correct metering block and some drilling. Ther are some mods to do what he wants, but Holley had disavowed the procedure sine the linkage can bind and cause problems or throttle shaft problems. I do agree, that if he needs a 'fat' pump shot, a single pump with the 50cc conversion and the biggest shooter may not cover it, and the double pumper is the ticket here to cover both sets of bores.

-D.idiot

Don't be cheap when it comes to your fuel delivery the fastest way to break something is from lean spikes. There all kinds of info on the net on modifying a DP. I can understand you already have a carb or two but my opinion is I'd sell them and pick up a 500 cfm two barrel. You have half as much to deal with.
I have a blow thru setup and there not hard to dial in for lower boost levels under 12 psi but when you start turning up, the boost that's were your going to have issues.
Just one man's opinion that's dealing with the tuning process now
Aaron

_________________
http://youtu.be/2Y4i4UOLiSA

http://www.forabodiesonly.com/mopar/sho ... p?t=126611

I ordered the book today. Gonna give it a read and go from there.I'm gonna go with the double pumper,i was just curious to see if it want gonna be a hassle to make the carbs I have work. also I'm only planning on running 8-12lbs of boost or whatever it can handle reliably using the boost referenced mechanical pump.

On a side note, I have successfully run my vacuum secondary carb with a screw in the linkage to make the secondaries open with the primaries. (not boosted) I put a larger squirter in it and adjusted the secondary float so that almost as soon as the plates open it's letting out fuel. Throttle response was awesome and there was no hesitation what so ever when everything was properly set. I wound up going back to the normal setup because it needed to be adjusted before each day of racing to work properly.it just got to be a hassle. I would not recommend that setup for street driven car for that reason. But if you like fiddling with your stuff it can be done with good results.

_________________
1966 Plymouth Valiant, 225, 3 on the tree, 8 1/4 3.21 sure grip, hyperpac, holley 650dp, holset h1c

will if you got it to work with no boost then that same carb will work with boost!! i had trouble with double pump 750cfm untill i got a looser converter.

so the book came in today and from my readings at theturboforums.com im gonna run the 600 dp. making a blow through carb has always in some part put me off of turboing a slant. if i would have known that it was really that easy to setup a carb for it i would have been boosted a long time ago.

http://www.hangar18fabrication.com/blowthru.html
that is a good writeup on how to do it if anyone else was concidering it. if you dont plan on running more than 10psi dont bother drilling. also another mod to make would be vent tube extensions.

_________________
1966 Plymouth Valiant, 225, 3 on the tree, 8 1/4 3.21 sure grip, hyperpac, holley 650dp, holset h1c

A 4 barrel is too much carb for 10 - 12 psi. I only plan on running a 350 cfm 2 barrel on my turbo build, plus it'll be better off boost than the 4 barrel as well.

_________________
1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

I run a 650 blowthrough barry grant demon daily driver and don't have any issues once I got the tune close.

Kev

_________________