I'm detailing my madness here just so I have a record of everything done.
Alright, so here is the situation. My 1976 F100 has a .030 over 390, 3.00:1 gears, RV type cam, of unknown low compression (runs on regular), Edelbrock performer rpm, with a QF 735cfm SS carb on top. I rebuilt the c6 a little while back with a 500hp broader performance kit. Sporty lil truck at 3800lbs. I'd wager it has a maximum of 300hp, tho this is speculation I don't really have a basis for any sort of number. Stock D2 heads, long tube headers, 2.25 exhaust with 12inch long glasspacks. Stockish converter, etc.
The Truck in question:
The usage for this truck has gone from fun street rod to highway flier. This is partially due to getting my 63.5 Galaxie on the road. The Galaxie has a AED double pumper which despite my best efforts still drinks too much fuel and isn't as snappy off the line as I'd like. It is a very very good carb without a doubt but I think the QF 735cfm I have on the truck would be a better carb on this car.
Due to my new usage of my truck as a strictly highway driver and around town beater, I was going to move toward the direction of fuel economy instead of high performance.
A little while ago I decided I'd find some old Holley and toss it on the truck, move the QF to the car and sell off the AED carb. Randy Millard listed a Holley 4010 600cfm carb on the FE forums May 2nd, I snagged it for I think $75 shipped. Autolite and Holley 4010 carbs have often been touted as a fuel economy type carburetor so this seemed like a fun little experiment, but when asked the difference must folks shrug and don't have realistic numbers.
My run:
I drive from my home to the airport to go to work. I work 28on and 14 off, so I drive exactly 70 miles to the airport, disconnect the battery and leave the truck for 28 days. I come home, get her fired up and drive the exact same route.
I fuel up before leaving, and I fuel up when I am on the way home at a station that is .5 miles from my house. I have been making this run 8 times a year for the last 7 years. I use exactly the same gas station for all fill ups. It runs 87 octane E10.
Seems like a perfect way to record fuel economy under the exact same conditions, with the exception of weather, which obviously cannot be controlled.
Currently fuel is $3.60 a gallon, so we'll use that as our constant even if fuel cost changes.
This means going to work and coming back I spend $44.21 per trip. I do this 8 times a year which costs $353.68
If I can get 15mpg with this experiment I stand to save at least $90 a year on just this run.
I average 11.4mpg on this run. It is south georgia highways, which are just flat straight 2 lane roads for 20 miles at a time, you'll go through a tiny town of one stop sign twice on this run. I drive 65-70mph and the engine spins 2350-2500 for the duration.
Carb as received:
I always loved the design idea of the Autolite carburetors, but it seemed they were always too small, and specific parts like jets were an issue
Accelerator pump needle is different, has a plunger that goes into a bolt with tiny holes. This one was totally plugged up.
The cool thing about this 4010 compared to the 4150 style, is honestly even after sitting for countless years, I *could* have taken this carb apart and cleaned it out without a rebuild kit. Aside from being dirty, I got everything loose with only tearing one gasket (which I could have made). The power valve tested good, the vac secondary canister held vacuum without leakage for 10 minutes, etc etc. I considered not buying a kit (as it was $40) and was just going to replace the needle valves. I called around locally and no one has carb parts on the shelf, I looked on summit racing, and a set of needle valves was $20-$30 so I decided to just get the kit anyway. The needle valves actually sealed and looked good, but I just didn't want to risk that they were made prior to the ethanol craze. An overflowing carb isn't much fun at 2am on the way to the airport. Either way, it is cool that I didn't NEED to buy a kit.
The fancy annular boosters:
Being a secondary vac carb, the boosters didn't have a shooter for the accel pump. It is replaced by a solid screw and no nozzles are in the holes. By the looks of it, this is the same as a mechanical secondary carb, same casting I mean... a lil drill work and some spare parts could most likely make it one.
Jets were frozen badly in the body. It even ruined my fancy holley Jet tool which now resides in the trash. I ended up soaking everything in pb blaster for a few hours. The body was rinsed out and a soldering gun was set in each jet for a bit. I got all four jets out, but they are not usable. The 4010 had 67jets in the mains and 78 in the secondaries.
Issues I have with the Holley vs the Quickfuel:
-Cannot change accelerator pump shot nozzle
-Cannot change airbleeds
-generally not adjustable in really any manner other than jets, pump diagram size, secondary spring, pump cam.
I do like that this takes holley parts that we've all got on the shelf, no specific Autolite parts. The issues I have above I believe have been addressed in the Summit version of this carb. I also love the design of the Autolite/4010 in that aside from accelerator pump and power valve cover, nothing else is below the fuel line that can leak. I also like the idea for a strictly street car of having annular boosters, I hope this equates to better low speed power and economy.
The kit should be here before the weekend and I hope to get the initial tuning done before I go to work on the 14th.
I'll repost my fuel records in 5 weeks.
Any thoughts and/or comments are welcome.
Thanks
Drew
