tire change or gear change

First of all ,here is my combo (357with World Pro.Roush cyl heads,comp cams xe 4x4 cam with an advert of 270/278 ,Edelbrock rpm and a Holley 750 .c6 with a 273 Low gear ,Tci breakaway.also a9" ford with 4.11 gears and a Detroit locker .seting on 27" Bfg drag radials ) my question is sin order to get a better launch should I go with more or less tire size or drop or raise gear ratio. this truck ways 4260 lbs and is shaped like a brick ,but oh well its paid for

How does it hook-up now ? I know trucks have trouble hookin at the line-

I would think that some 4:56 gears would help, but that might just help spin the tires more. what kind of suspension do you have under it ?

with street tire's ,alot of spin and wheel hop .But with the Bfg's alot less spin but still wheel hop. I have stock suspention with spring clampswitch seem to help .

If you want it to hook, get a set of Cal Tracs.

Calvert Racing, home of CalTracs, "The Bar With The Bite"

Also, Comp Engineering make's their slide-a-link which is similar.

Also, through about 300lb agains in the bed against the tail gate! (May not accelerate, but it'll hook). The name of the game is weight transfer my friend! The amount of forward force the tires can apply is equal to the co-efficient of friction between the road surface and the tire TIMES the vertical weight of the tire. If you have 1500 lbs on the rear tires and a coefficient of friction of 0.8, the you can only use 1200 lbs of "thrust" to accelerate. (1500 x 0.8 = 1200). If you apply any more than that, you'll just spin. Cal-Tracs will help out with a) weight transfer, and b) use suspension jacking forces applied by the drive train to help "plant" the rear axle.

It is virtually impossible to get a coefficient of friction greater than 1.0 (and that is difficult) on street tires or slicks with out some sort of adhesion treatment. (Hence the burn out, track treatment, and tire prep). There are two components of traction: 1) Adhesion, and 2)hysteresis. (If it rains, adhesion goes to ZERO, and all you're left with is hysteresis, which are the forces available by the deformation of the tread on the tire). Adhesion is your only hope to get the coefficient to get above 1.0. Top Fuel dragsters are in the 4.0 to 5.0 range, and it's all adhesion!

Weight transfer, weight transfer, weight transfer.....then expect to start breaking parts!

Best of luck!

Are you getting good weight transfer to the back???
Might need some tracktion bars..
I'm running a 466 with a 9" tru track with 350 gears and 26" street tires, and masave 7 leaf rear springs in a 4500 lb truck (in signature) prob 450 hp tq. (aprox) MY front end it real light and when I mash the go pedal the front end raises up and almost comes off the ground throwing all the weight to the back. Havent dynoed it yet.. but I don't have any traction probs... So Far I've run a 14.5 best time at the 1/4. but I haven't recurved the dizzy yet or calabrated the carb yet.
Tim

The application chart shows that they don't make them fer older trucks, I have no idea what im gonna do for my '69 f-100.

Replacing your leaf springs with a 4-link or ladder bar with coil over set up would give you a lot more traction and elimination the wheel hop. If they don't make, or you can't make fit, a cal-trac, then those are about your only choices.

Another option could be to lower the truck and flip the axle on top of the leaves. It'll slightly help your traction and wheel hop situation, but it won't get rid of it.

I had a '93 F150 that I did a 4-6 drop (4"front, 6" axle flip drop in the rear). It drasticly improved the trucks handling and slightly improved it's acceleration. Although, it did decrease the amount of wheel hop, I've heard of people reporting the same or worse wheel hop after flipping the axle. I guess each truck reacts differently. Don't get me wrong, lowering the truck and flipping the axle only improves the situation. It still didn't hook up like a cal-trac, 4 link, or ladder bar set up.

so what did you do to lighten the front end ? I here that removing the sway bar helps ,removing creature comforts ( thats a no no )

well your right they don't show an app for older trucks But what about a pair uf slappers from Lakewood ?any comments on those