Hey fellers, I was just looking for some outside opinions on tire/gear combos. I am doing a frame off resto/mod on my 84 F150 4wd. The truck currently has a 4" suspension lift with 33s and 4.10 gears. I am replacing my rear springs with enough arch (lift springs) to hopefully be able to get rid of my lift blocks. Also I am adding a set of Superlift extended tubular radius arms up front to give me more flex and a better ride. Any way I have been tossing the idea around of lifting the truck 2 more inches and adding 35s. My question is for those of you running a 300 six. Are 4.10s deep enough for 35s to where the motor can still spin em decent. Right now with 33s the truck has plenty of *****, I am worried about losing it if I step up to 35s. Anyone running a six cylinder with 4.10s/35s... BTW I am running an NP435 trans. Thanx for any feedback!

 

you will lose about 200 rpm at highway speed by going to the larger tire. The added weight will also have an effect on performance.
4.56's will spin the engine around 2460 rpm at the same highway speed, but will drive much better at lower speeds. The truck will accelerate better with a lower gear, if you can handle the higher rpm as a compromise.
Heak I would just try the 4.10's and see how you like it. Since you are running a manual, you might get away with it.

 

I am already turning 3000 rpm at 70 mph right now with my current set up. There is no lack of power running around down the street or heavier towing. IMO I am actually geared a bit low for highway use, but it is tolerable. This set up works very well off road... plenty of grunt to climb up steep hills in the sand dunes and the ability to keep the tires clean in the mud. Really the durn thing is a bulldozer, it will pull anything and go almost anywhere doing it. The motor isn't stock of course: .040 over, RV cam, Offy intake, header, carb, ignition... she's a runner no doubt it.

 

Stay with 4.10 gears if you go to 35s
You have that granny low, so you should be plenty good on the acceleration side of it.

35s will lower your hwy RPMs, giving you better mileage, and this way you won't wind out the motor staying at 3,000 RPMs.

Also the 300 as alot of low end torque, and you built it, so acceleration isn't a problem, don't worry about it.

 

when i was first starten out i had a 300ci with 6" of lift on 35x16 boggers and that thing span them easy, and i had a pos 5spd.

 

Thanx fellas I am pretty sure I will still have enough power to spin em, just wanted to make sure. I am planning on replacing my Holley 2300 2bbl with a 500 Edelbrock 4bbl and adding an MSD 6AL box to compliment the Blaster Coil I already have. Also I am going to a 3" single exhaust system, not sure what muffler to go with though. I have already run a Flowmaster 40 with fake duals... time to change it up.

 

Hey, I stepped up to 36s with the 4.10s and love it. I used to run 33s also, and it was great offroad and around town, but just a few miles at 65 or 70 was enough to make me want overdrive or bigger tires. I am really happy with the setup. I personally rarely drive over 3000 rpms, so it works out well.

 

Yeah my truck doesn't see much over 3000 rpm either, except either running in the sand dunes or in the mud. I am hoping to be picking up an 88 F250 4wd with a 351/C6 late this summer for a plow truck/ toy hauler, so trailer towing won't be a big concern anymore.

 

Hey, when you get a chance, post up some pics.

 

I have been meaning to post some pics but can't figure out how to do it, i am slightly computer declined.