Will a 38" tires fit under a 84 ford F-250 4x4 with a six inch lift without fender trimming or will I have some rubbing? If it does need some fender triming how much?

 

My suggestion would be to put them on and test it out.

Dk

 

you will also have to regear with those 38's on there.

 

Itll look nice. Do it up.

 

What kind of gearing would I need? My drivetrain will be a 400 V8 with edelbrock carb, intake, cam, timing chain and gears, and also valve springs and lifters. C6 tranny and NP 205 t case. I have 4.10's in right now.

 

The 4.10's will be fine. Some people prefer to regear to retain as close as possible to stock gearing with the bigger tires. Saying you will have to is incorrect. I've never regeared any of my 5 lifted trucks I've owned.

 

well here are 4 Reasons To Change Your Gear Ratio............................1. TORQUE TO THE REAR AXLE WILL BE GREATLY IMPROVED - the fact is that even a simple change from a 31" diameter tire to a 33" diameter tire will affect the amount of available torque by 10%. .................................................. ...............STRESS TO THE DRIVELINE WILL BE GREATLY LESSENED - modern day transmissions cost $600 or more to perform a basic overhaul. Driving with even a 10% larger tire will result in the transmission being under the same load as always being driven on an incline. The transmission may not suddenly fail, but the life will definately be reduced by thousands of miles.........ENGINE EFFICIENCY WILL BE REGAINED - RPM alone does not affect fuel milage. A undergeared vehicle as the result of oversized tires will result in a substantial loss of fuel milage. Also, just as with the transmission, your engine life will greatly be reduced miles. .................................................. .....
SPEEDOMETER/ODOMETER ACCURACY WILL BE REGAINED - with kits in the $100+ range to calibrate speedometers after tire swaps, it seems pretty important to have an accurate speedometer, which can also be fixed with a simple gear change.

 

Rebelbob,

I'm not saying that there aren't plenty of good reasons to regear. I'm just saying that it isn't necessary. Don't wanna fight.

 

Well, you're both right anyways. He doesn't NEED to re-gear but its always a good idea when you jump up that much in size. My thought is though, don't you guys think his ride is going to be pretty gutless with that 400, 38s, and he keeps the 4.10s? I'd think so...

 

id say so too.

 

I think he can probably make that determination himself. I just wanted to let him know that it is not something that has to be done. Some come here on this board and have very little knowledge and I didn't want him to think something would be destroyed if he didn't regear. Kinda like when someone who doesn't know anything talks about driving around town in 4x4 and we all scream for them to stop before they spit out a driveline or break an axle u-joint.

That's all.

 

whats wrong with driving around town in 4x4?

 

I will probably regear to 4.56's, but what I was wondering from the start was if 38's would fit on the truck ofter a 6" lift (skyjacker). The tires I was thinking about were boggers or Super Swamper TSL's (radials are crap) MO. My motor will have between 300 and 400 hp.

One more ? what CFM size carb should I get. They say 650 in edelbrock but I was thinking more around 750.

 

As for the 38 inch tires, they will barely rub if they rub at all. I have 36 inch swampers with no lift and they barely rubbed on my 86 F250. I've since cut the shiznit out of the fenders to fit 39.5 boggers. I would recommend a 600-650 on the carb. It will run good. I have run 600 edelbrocks on hopped up 460's with good results (good driveability and dependable tune). If you want the absolute best carb for your engine and have $340 burning a hole in your pocket, get the 625 road demon vac secondaries. Great carb!!

 

One more thing... I noticed that your name is Ford MUD Runner. I assume that you will use your 300-400 hp V8 and 38 inch mud tires to drive in the mud and not so much for grocery getter duties. You need wheel speed in the mud and will have acceptable performance with 4:10 gears. If you can afford 4:56 or 4:88 gears go for it, but I feel the money could be better spent elsewhere first, like front and rear lockers. You also can't go wrong with a 12000 lb winch on a heavy duty bumper!!