I have a few Questions

Paul Merrell · Post by **Paul Merrell** » February 19, 2007, 7:59 pm

First question I have a stock 4v intake and a 4100 carb 4 barrel I need a spacer plate under the carb should I go with a open spacer plate or a 4 hole spacer plate I want the best performance and fuel economy I can get the engine is stock . Second question I am using a pertronix ignitor in place of the points what spark plugs would be best and what gap on the plugs. To get the best performance and fuel economy. I am using a 195 thermostat also.

Uncle Skip · Post by **Uncle Skip** » February 19, 2007, 8:08 pm

Paul.
I'd go with the 4 hole spacer, not more than 3/4" thick. This will increase the low end torque.
On the Pertronix, set the gaps between .040-.045" to start with and read the plugs after 100 or so miles. Depending on compression, you might have to go as far as .050" to make it work effeciently.
U@ss

Paul Merrell · Post by **Paul Merrell** » February 19, 2007, 8:15 pm

Thanks Skip :!:

Should I use motorcraft plugs :?:

ICEMAN6166 · Post by **ICEMAN6166** » February 19, 2007, 10:46 pm

Paul, make sure you get a thick gasket or a phenolic spacer to prevent percolation in the carb. FEs like to do that especially in the summer.

guess i need to check my wifes spark plugs now to see what the gap is, it has a pertronix but i did not install it and have never looked at them.

winr · Post by **winr** » February 20, 2007, 3:01 am

Hey Paul.

Make sure the spacer plate is wide enough or you will have vacuum leaks.

A stock Ford spacer is 5 3/8" wide and 4 13/16" long measuring center to center.
You have to use the correct 4100 gasket also as the Holley type gaskets are to narrow unless you use a 4 hole gasket that has the same size throttle holes.

Most aftermarket spacers are 5" wide and usually are long enough.

You can get away with using a narrower 4 hole spacer if the throttle holes are
real close to the size of the throttle bores on your 4100 (around 1 9/16") and you use a gasket that mathes the bore sizes.

Basically, if you seal the throttle holes and the front section of a 4100 it wont have a vacuum leak, the sides of the 4100 could overhang.

I have pictures and part numbers if you need them.

Richard.

Paul Merrell · Post by **Paul Merrell** » February 20, 2007, 6:52 am

Is this a good spacer that will work with the carb 545-64930 it is a 1" rise its for a Holley 4150 and 4160 from SpeedwayMotors.com

winr · Post by **winr** » February 20, 2007, 9:58 am

Is it this one?

http://www.speedwaymotors.com/pl/2005,5 ... acers.html

That looks like the one I am using except mine is aluminum.

I may buy one like it myself.

You will need 2 4-hole gaskets (of course), make sure the holes in the gaskets are close to the size of your throttle bores in the carb.

You might look at FelPro/ROL, part number 60059/CM55144.

I drilled and threaded a hole about half way through the spacer for a brass pipe nipple in the back of the spacer in the center and then drilled 2 small holes at an angle into the 2 back holes to hook up my PCV valve.

Richard.

Paul Merrell · Post by **Paul Merrell** » February 20, 2007, 8:55 pm

Yes that is the one I am talking about. What is this phenolic to prevent percolation :?:

Are you talking about vapor lock :?:

We use clothes pins :!:

ICEMAN6166 · Post by **ICEMAN6166** » February 20, 2007, 9:15 pm

phenolic is a hard fuel resistant plastic.its an insulator. percolation is the noise you hear after you shut off the engine before you get vapor lock.
if you like the clothes pins and they work, dont let me talk you into spending more money.

64 f100 · Post by **64 f100** » February 20, 2007, 10:44 pm

The Petronix won't give you hotter spark from a stock coil to the best of my knowledge. The wider plug gap may or may not work efficiently without the higher voltage coil, you can get from Petronix for about 35$.

Rich

Paul Merrell · Post by **Paul Merrell** » February 21, 2007, 6:56 am

Iceman I didn't know that was how vapor lock was cause and I didn't know that was a way to stop it without the tacky clothes pins :!:

I guess you learn something every day.

Paul Merrell · Post by **Paul Merrell** » February 22, 2007, 8:46 pm

I have another question I am rebuilding the carb 4100 its a C3AF-T its for a 390 police car my question is the jets the primary are 52 and the secondary are 52 I thought that the primarys where smaller than the secondarys. If so can I put a 42 in primary and a 62 in the secondary I tried to call holley but its too late. I know its not a holley but I thought they might help. Does anyone have a sugestion. I know the carb has been rebuild before but not by me. I got it from a guy in Washington State.

winr · Post by **winr** » February 24, 2007, 6:12 pm

Hey paul.

Go here, there are a couple of guys that know all of the size jets for the various 4100's.

http://www.carbdford.com/viewforum.php? ... fc19f29c85

Also, ask about putting Holley jets in 4100's also.

I heard after 1964 or 1965 the 4100's used different threads than a Holley.

Richard.