Hi everyone, I am looking for a little bit of help here. I recently bought a offie intake and Holly 4160 carb off ebay. This is going on an '84 F-150 300 I6. Everything is stock, exhaust is simply a strait pipe with a single glasspack. My problem is that this carb is a 600 cfm unit, and I have been told that this is way too big for the 300. I am "stuck" with this carb so I am going to make it work. I have come to realize that I am most likely going to need re-jet, change the power vavle ( to a 2 stage) and increase the strenght of the secondary springs. I need to do this inexpensivly though, i do not have the money to buy a wide range of power valves and jets to see which works the best. I am looking for any advice on what sizes of jets, power vaves or sprong tensions I would most likely need. I know this is asking specialized information for MY vehicle, but, if any one out there can give me a jumping off point, or any other information on how to adapt this carb to my application, I would really appreciate it. Thank you! And, feel free to email me.
Eric
Oh, truck is stick, stock cam, power brakes (if that affects vacuum)

 

so I hope you still have the truck and figured this out, but I figured that I'd give you an answer anyway. I'd find a way to get the linkage to not run the secondaries at all. I ran a few carters at 625CFM with my setup both before and after the performance upgrades, and I gotta tell you that as a 2 barrel the carb works pretty good. It will fall on it's face a bit above 3500 RPM like this, but it won't run dangerously lean, and it really shouldn't be above 3500 that much anyway. Other than that I can't really help ya. I ended up going with a truck avenger 470 as my final choice, and am in the middle of wide band O2 tuning it.