Hi, I'm running the standard holley 4160, 600cfm, on an f150 360fe 4x4 with performer intake. It's been fine, but after 5 years some of the gaskets are starting to leak. I'm setting aside the time to do a basic rebuild with the holley kit. Any suggestions (besides buy a new/different carb) on tweeks to the carb while I'm in there? I rarely get above 3K-4k rpm, and am always looking to squeeze a little more torque/pulling ability out of the "yellow banana". THanks.

 

Before tearing it off ,take some vacuum reading , then match the power valve and secondary diaphragm spring accordingly .

 

I'll go ahead and do that.

I've been reading up on the differences between 1 and 2 stage power valves...not sure if a 2 stage will really make any difference (in fuel economy) vs a properly tuned 1 stage. Anything to get slightly better mpg than the space shuttle.

 

Stick with the single stage power valve. You want a PV sized two numbers below your vacuum reading at idle in gear. That's a general setup and I probably wouldn't run a pv much over a 10.5 in a stock 360. Make sure to purchase a Holley rebuild kit only. Take your time and clean all passages. Watch for small steel ***** and plungers. Blow out with compressed air afterward. Check for any throttle shaft play in the bores. This is a source of vacuum leaks. Have you set the accelerator pump linkage for .015 of play?

If it ran fine; just clean it and rebuild. Don't adjust anything except the idle mixture screws.

Have you had your distributor recurved? It makes a world of difference. If you are running the factory 6*BTDC... adjust it out to 10-12*BTDC.

Give her a good tune up and add some air to the tires. I run about 5 more psi up front. Mileage is not synonymous with FE engines. If you want a bit more mileage; go back to the Autolite 2100 carb and stock intake.

 

The rebuild went fine. It was a leaky gasket between the base plate and body. That cured the running like crap problem. Installed the new PV that came with the holley kit (which I think is a 6.5 - the numbers were hard to read though); ran it and had a new problem - lean stuttering at WOT. Put the old PV back in (which is a 6.5 - the number stamps were legible on this one) and the stutter cleared up. Go figure. The truck pulls about 16-17 of vacuum at idle, and dips to 8-9 at moderate acceleration from cruise...so I am going to try a 7.5 pv, just to see if it makes a difference. Set the idle mixture and timing (stock ignition sys) by vacuum - so everything's good there (as far as I can tell there are no vacuum leaks and no pre-ignition).

Main problem now - I need to get the spark plugs looking better. They've been nearly bone-white with very little depositing, since putting this carb on 4-5 years ago (new, out of the box, with no tuning) - which now I realize helps to explain the slight engine temp increase (but still within normal) at cruise speeds.

I'm thinking main jets. Whatever is the stock jet size of this carb, that's what it has now - 64s I'm assuming, but I'll have to pull them to check. Considering there's no discernible performance issue (besides the plug color and minor temp increase), I'm going to jump up 5 or 6 and go from there. Any thoughts?

 

Just noticed you are in Oracle. I'm in Glendale. Do you have the crappy oxygenated fuel there? If so; your plugs will look white. Look far down inside the plug where the ceramic meets the metal portion of plug. What color do you have? Now look at the first thread on plug that the strap is attached to. Is it black at least 3/4 of the circumference? Use a magnifying glass if you need.

Here's something to try. Get her warmed up and find a level stretch on a side street. Cruise at about 30mph with a steady foot. Feel any surging or stuttering? That would indicate a lean cruise. You should be pretty close with a 64 main.