Howdy,

I have a 173 ci (overbored .050) Chevy v6. It has ported everything and is pulling 14 inches of vacuum at idle and up to 22 inches cruising. The carb is the Holley 4160 mounted on a Torker II intake, running the light yellow spring and #49 jets.

I have a 1000 - 2500 rpm stumble when the engine is hot. I've experimented with the orange and green accellerator pump cams, and shooters from 25 to 37 but no help. I've tried power valves from 4.5 to 7.5.

I am thinking I may need to go to the 9.5 or 10.5 power valve. Does anybody have experience with this problem?

Arn

i just removed a weinad accelerator. those intakes suck donkey balls.

the torker II is your problem

what vacuum are you making?

the reasoning behind it: its a 360 intake the max cfm is allowed to each cylinder. you need a dual plane 180 style that way only half the availible cfm is availible that the carb can flow. unless your running feul injection, or a high stall, you need a dual plane to drive around period.

I should have been more clear.

The Torker II has a dual intake top. I originally had the Holley 2300 2 barrel, but it had the same problem and I blamed the carb. I sent the 2300 back to Holley and they did some metering block work. It still had the same problem when I got it back so I installed a new 4160 but same problem again. I have the canvas phenolic spacer and a Derale control system for temperature. My carb doesn't get over 105 degrees F. I haven't used more than 7.5 on my power valve, and I have read that a 9.5 power valve with 14 inches of vacuum at idle will close up the gap between the transfer slot and main fuel system.

Other guys I know running the split plenum Torker II with the 4160 on 3.4 v6's have not had the problem and run 6.5 power valves. I am really stumped why this engine is doing this.

Arn

look you are going to have poor driving characteristics with that manifold anywhere under say 3500.

quit changing carbs, and enjoy your manifolds operating range.


hey wait ...guys, more than one other person is running this rediculous combination ? is this a case of the blind leading the blind? or mistaken manifold name?

I had the same problem with a Torker 2 and a Holley 4150. Nothing I did solved the problem. You can lessen the problem by shortening the primary shot stroke but your diaphragm will wear out prematurely. The Torker 2 works best with an annular discharge carb. The smallest one Holley makes is a 750 which is too big for your combo. The 6.5 power valve is fine for your set up.

Thanks Bracketeer,

So if your Torker II didn't work out, what manifold did? Is there an alternative manifold you can recommend?

Spankynuts, does the phenolic spacer create a flow problem? it is easy to remove if it does.

BTW, I have a 4.5 power valve on it currently and the problem is more manageable. I had a 25 shooter but I was getting hesitation so I switched up to a 31 with green #1 hole cam. It is running good for about 3/4 hr before it starts to misbehave.

Arn

I used that engine for 3 years and never got rid of the stumble. I had it running 13.3s in a stock 79 Vette with street tires. I sold the motor carb to oil pan and built a new 400.

Thanks for the info. Are we talking about the open plenum or the dual plane?

Will the dual plane improve the stumble?

Arn

Thanks for the tips guys. I looked up the Torker threads and then phoned Edelbrock. They definitely do not recommend the open plenum or an open spacer for the Torker II. They told me there are definite signal problems to the carb under 2500 rpm if the plenum is open or you have an open spacer.

I'm pretty glad I finally logged into this site.

Arn

From the delay in stumblng it sounds like its less of a carb/intake problem and more of a timing curve problem, try leaving the intitial timing alone and adjusting the curve to come in more slowly. If you can't do that you can also try to just pull out some initial advance, howver that's more of a crutch than a remidy

The vacuum advance distributor was set up for 25* total advance by a pro shop.

My engine is currently at 11* base advance. When I changed from the ported vacuum plug to the full vacuum plug, (which advances your idle timing way high), it made no difference at all to the stumble. (The stock timing is 10*for the original MPFI system BTW)

I went to my Pontiac mechanic and we discussed fuel delivery. I was able to eliminate my fuel pump, maybe not my Mallory bypass regulator, (I still wonder about that one). This 4160 carb is brand new, and one of 3 different carbs, with all the same problem. (a flattrack 2300, a street 2300 and this 4160) I tested my distributor module, replaced my coil, and I have no computer to play with.

The car pulls really strong from 2500 to 6000 rpm. and also does really well idle to 2500 when it is cold. This problem comes up when it is hot.

After my talk with Edelbrock, I replaced my phenolic open spacer with a Mr. Gasket 4 - hole phenolic and the problem didn't leave but became much more managable. Tonight I am removing the spacer to see if this is a runner length or plenum size problem.

My problem is that I think it is the Torker causing the problem, but I don't see alternative choices out there for the 60*v6