beefing up 1987 F150 4.9/300 I6. putting 35" of rubber on...

Long bed style, 4 Speed, Im looking at putting some 35" of rubber under, I'm looking at using the rough country lift kit that's 6". I guess that's a good enough brand to use.. How about since I'm putting them large tires on will I need better gears to stabilize the power I had with my little 26" tires? What else would really help that straight six get them wheels spinning with great torque on the streets and on the beach plus out at the mud bog?  

Definitely gears.

If your transmission has overdrive, go with 4.56 or 4.88 axle gears. If no OD, then something around 4.10 should be good to get those tires turning.  

I'm not sure if it has od.. I havnt seen anywhere. What about the gears for the front wheels for when I put it in 4wd? And do I have to have a 6" lift for 35" tires? Can I go lower? Thanks a lot for the help, I'm looking at beefing up the engin first before I get a lift. I have efi, so, I'm looking all over for more info on things I can do to this motor, choices to make.. U know.. I just flushed a lot of dirt out of the radiator and took the old thermostat out and sprayed out the dirt and rust stuff out until I got clear water.. What should I do next? I'm looking at getting a camshaft and complete higher performance parts. But nothing really major expensive and not drag race parts.. Just, u know. Currently I'm replacing the clutch too, got the bell housing off and old worn out clutch off.. Bearing is shot too! Flywheel has lil spider cracks here and there..  

Billy, if performance is what you are after, then don't spend a dime on performance parts for the I6.  Save your money and build a V8 that you can drop into the truck at a later date.  Since those trucks came with the 302, 351W, and the 460, you have the choice of running any one of those motors and being able to use factory parts for the swap which makes it very easy to do.  You simply won't get the performance out of the I6 that you will want and need for playing in the mud and sand, sorry.  Also, you say the truck is a 4spd, is it an auto or a manual?  If it is an auto, it has an overdrive and you can go with a lower gear ratio in the axles than if it is a manual.  The lower axle gears will help the motor to put all of its generated torque to the ground faster than the gears that you have now.  Think of the gears in the differentials like the gears on the back wheel of a mountain bike.  The larger the gear, the lower the ratio.  This is why its easier to pedal a mountain bike uphill when you are using the largest gear on the back wheel.  The same principal applies with larger tires and lower (numerically higher) gears in the diffs.  I concur with SFR, if you have an overdrive, go 4.88s with the 35" tires.  However, even if you don't have an overdrive, I would go no less than 4.56s.  35" of rubber is still alot to turn, especially using an inline 6.  You will need all the help you can get.  As far as suspension options, Rough Country is a quality brand, you'll have no problems with them.  You could probably get away with a 4" lift to run 35s, but if you are playing in the dunes alot, any time you stuff the suspension hard, you will have tire to fender contact.  Hope this helps.  

Yeah, thanks for that great info, sorry you had to waist your time telling me about an od system, it has manual 4 on the floor. I just sold my other 93 f150 that had a 302.. I just didn't like the truck a all. It just reminded me of bad times in my life. I'm wanting to stick with this straight six to save fuel!!! Well, if the fuel differences were not very different I want t o go big or stay home. So I was planning on maxing out this six.. But I don't want to blow it up. Hoping it will last another 200,000 miles or more! Well, I don't think I will really be playing hard in the mud and sand, just to take a light cruse down the beach to camp out with my girl, or drive through some places to get to a lake, maybe run it in the mud bog contest a few times.. Or tow the boat to the beach and launch it in the surf or at dock. I don't want my tires to rub when I'm turning sharp.. I'm coming across alot of different brands of lift kits and they all are saying 6" 35s but I've heard a couple people say 4 will do.. Currently, I have the truck jacked up in the drive with the clutch out, it's my first means of expense.. Radiator off, bench seat out, carpet flooring out.. I was gonna take the bed off and start on sanding and painting the frame to withstand the weather around here..  How's it soundin? Thanks for the replies!  

Ok, so a manual 4 spd, no problem, great tranny if it has the granny low. If you're going to be flexing it out, and actually using the truck, then go with the 6" lift.  It will pay dividends later.  Go with the 4.56s for gears, that will be the best compromise between on and off road manners.  Go with a Detroit locker in the rear and a good limited slip, like a PowrLok or a TrueTrac up front.  That wat you will still be able to turn rather easily.  If you're set on sticking with the I6, then you need to focus on building the torque that the motor will produce.  I6s are not known as hp motors, so dont waste time trying to reinvent the wheel.  They are known for great off-idle torque, so that's what you need to exploit.  Focus on things like building compression up.  Compression makes gobs of torque.  You want to be at least 9.5:1.  You'll have to run 91 octane, but the performance difference will be worth it.  Look at camshafts with shorter overall duration and higher amounts of lift on the exhaust side.  The better an engine breathes, the more power it will make.  Look into a good header from someone like Doug Thorley, or Hooker, or Hedman.  Combined with a nice 3" free flowing exhaust and that will be a big help.  Also look into an aluminum intake from someone like Edelbrock or Weiand.  I don't know if they make anything for the I6, but it's worth a shot.  Get a good, high flow air filter from K&N or Airaid or someone like that.  Maybe also look into bigger injectors and a chip or having the computer re-flashed.  This will all be a considerable amount of money, but if you do it right, then there's no reason that the engine shouldn't be above 300 hp and deliver high teens or better mpg.  

I'm loooking at all these different lifts that are out there and I can't stand that 'stilty, tipsey, top heavy' look.. You know, you see it all the time on trucks. That weird, 8" lift with 31" tires look.. I'm looking for a little more snug fit look.. If you can go here http://www.fabtechmotorsports.com/applications/ford/4wd81-96f150.html this truck looks great! Says it has a 6" lift with 35" tires.. But is that photo edited or what? I'm loving the way this seems,, but is this lift gonna be worth it? Look what it comes with, apparently it utilizes the factory arms,, I believe this lift runs about $800. And only comes with blocks for the rear.. I don't think it's worth it. Or what am I missing?? Well thanks for that much spectacular help! And yes I have granny low. When should I use it?  

Something certainly does look screwy with the rear tire of the truck in the pic on that page. I would say the proportions are not out of line though.

Something I would strongly suggest though is if you get that kit (or ANY 6" lift for that matter), get the #FA600 drop pitman arm from Skyjacker Suspension, as for whatever reason I don't understand, the drop arms included with all the kits sold for these trucks (even Skyjacker's own 6" kits) are too short and won't line your steering back up properly (leading to poor handling and rapid tire wear). The FA600 arm isn't exactly cheap, but it will still pay for itself many times over in tire savings alone.

If you want, you can go with a 4" lift and if needed, trim your fenders for the tires to fit. The amount of trimming would be very small (might be limited to just the ends of the front bumper itself). This would give you more of that 'snug fit' look you're after.