kilgorq

I have a holley 4160 Vacuum secondary that I am trying to dial in. It has been over a decade since I have messed with a holley carb and I am not remembering it very well. The Carb came off of a 390 and I did a rebuild on it. I put it on and I have a couple of problems.

Car specs
306 with a stock roller cam. Stock intake and exhaust. Except glass pack mufflers. (Old School)
3.73 behind a T5. Basically a stock 85 GT.

1) Hesitation when I punch it.
2) Surging at mid range steady RPM. about 1500 to 2500.

It had a 31 squirter in it. I put a 28 and now it is worse. ( It almost dies when I punch it then catches itself and roasts the tires) I am thinking I need to go up in squirter size (35) but I am not sure how problem 2 interacts with problem 1.

Original 4180 Carb had
Squirter Size. 28
Jet size. 58

Senario 1
Squirter Size. 31
Jet Size 64.
Good Idle after choke shuts off. Surging steady state midrange RPM. Hesitation under hard acceleration.

Senario 2
Squirter Size. 28
Jet Size 64.
Good Idle after choke shuts off. Surging steady state midrange RPM. Major Hesitation under hard acceleration.

Also The 4180 had a ball in the squirter tower and the 4160 has a needle. I thought about changing the needle out for the ball. It this OK to do?
What combos have worked well for you guys?

mjr46

if it's a 5 speed car a mechanical or weighted secondary car like a edelbrock will give a better thgrottle response... what size is the 4160??? I wouldn't have more than a 600 on a fairly stock 302.. I put on a edlebrock 1405/600 and right out of the box it was tunned very well..

kilgorq

600 CFM. I have considered edlebrock but I have budget constraints. Plus I think this carb is a good one. It just needs dialed in. I am thinking too much jet and not enough pump. Going to try Squirter 31 with Jet 58 next. That is if it ever stops Snowing here... We have gotten 10 times as much as normal. Its kinda hard to check out your accelerator pump on ice.[:@]

mjr46

^^^^you can change the ramp rate of delivery on most holley's by changing the cam on the accelerator pump arm linkage

Gary H

Change the pump cam, the assortment is cheap. This will help
http://www.carbdford.com/tech/Holley20PumCams.gif


What secondary spring are you running? Power valve? I bet it's a lean surge. You might want to get the metering plate to block conversion so you can change jets on the secondaries too.

mongolchuck

I had to change the pump cam on mine from orange to blue. It gives a quicker shot. Also i'm running a #40 shooter. Most of the hesitation is gone but i also have some tinkering to do. Altitude plays a big role in jet size. The higher you are, the smaller jet you need.

kilgorq

Out of pure frustration I went and bought and edelbrock 1406 and it does not fit. The Lever for the choke mechanism runs into the valve cover. I called Edelbrock and they said use a thicker Valve Cover gasket. So maybe I am an idiot but how will that fix the issue. Raise the valve cover up to stop the carb linkage from running into it. I already have a 1/2" Spacer on it but it looks like it needs another 1" to work. My concern is hood clearance. I dont think I can raise it up another inch and still close the hood.

kilgorq

Eldelbrock 1406 Will fit with a 1" spacer on a 1985 5.0 stock Intake manifold. Not quite as responsive as the Holley but not bad for bolt on with no calibration. Choke High Speed Idle is difficult to get to. And unlike the Holley it is located on the same side as the accelerator cable.

Gary H

A thicker valve cover gasket will move the valve cover out, not up. The heads are at an angle. What intake? Stock with the EGR?