Where to locate weight?

[Pyrotechnic]

As far as drag racing goes, where is the best place to move heavy things? Just before the rear axle or just behind it?

What about counteracting the torque that plants the drivers side tire and lifts the passenger? Do you move weight towards the driver or passenger side?

The truck is a 77 GMC long bed. The suspension will be leaf springs with cal trac bars.


My orginal plan - on the left of the pic

Gas tank - I had planned to weld a sump to the rear of the saddle tank on the drivers side (having a passenger tank is a bit annoying at a busy gas station). The truck would also have the passenger side tank in the event of a long trip.A small pump would move the fuel from it to the drivers side.

Spare tire - stays in the stock location

Battery and jack - It's a long bed, so there's extra room in the rear part of the bed where I can get the battery tucked up just in front of the spare tire. There's also room for a small hydraulic jack under the bed floor as well. I'm tired of having it flying around behind the seat.

My new idea - on the right

Gas tank - Both saddle tanks are ditched in favor of a 16 gallon fuel cell in place of the spare tire. The truck doesn't get driven as much as it used to so this capacity is fine. I could even bolt a saddle tank back in for extended range on a long trip if needed.

Spare tire - it would get mounted just above the fuel cell in the bed on hinging mount, so it could be flipped up to allow access to the fuel filler. The mount would also allow the tire to be quickly removed and secured in the upright position in the front left corner of the bed for when I need to haul stuff. Best of all, it will much easier to get at than the stock under bed mount.

Battery and Jack - same place as before

On the street, this arrangement should help get more weight over the rear for rainy weather. At the track, this allows the spare to be easily removed for weight savings and moves the weight of the gas tank back as well.

What do you guys think? Am I on the right track here moving stuff behind the axle? What about placing the battery and jack on the passenger side?

[hotrod 80]

Last truck i sumped the factory tank . This truck fuel cells . Is the truck a spare or daily driver ? I have a cell in my 49 and hate it . The cell in the Luv is for safety reasons . Moving the weight as far back as possible is best if removing it is not an option . Oh and were it says jack it should say bottle

[BigDan3131]

I have 2 batteries behind the axle and my fuel cell is mounted in the bed behind the axle as well. If you can get rid of the spare and get one of those space saver types you can put anywhere. That way you can either mount the cell underneath the bed or like half way in case your truck is real low to the ground. They make drag type fuel cells as big as 20 gallons and or if you have the money you can get a road racing style that holds up to 32 gallons. Get the aluminum ones over the plastic type, I say this because every plastic one I have seen mounted in a truck the tops get sucked in looking like crap. If you never plan to use E85 or the like get one with fuel cell foam installed it reduces slosh and aeration.

I would concentrate on all your easy upgrades first. Make sure your brakes are up to the task of slowing you down as you progressively get faster. Have the rearend gone thru and upgraded where needed such as either new axles with Ford type bearings or C-clip eliminators all new bearings and seals. Get the lightest rims that will fit with either a 15 x 4 up front or 15 x 6 so you can drive it anytime because little 4 inch wide rims aren't that great at helping you to stop on the street IMO. 15 x 10 should fit in the rear but maybe a 15 x 12 will. Replace the bushings in the leafs with either urethane or solid but greasable ones. Do the same up front, all new bushings and stuff. Shocks are important too, more so the faster you what to go. A roll cage should be installed having the bars tucked tight to make it less obvious on the street.

What I'm getting at is don't just stuff a monster of a motor in it and expect it to hook without any prep work first.

[Marv D]

Because of the torque created by the pinion twisting on the front of the differential, it tries to lift the passengers side tire. So put all the weight you can over the rear passengers side tire to compensate and help plant it. If your not hitting it with 350+ REAR WHEEL HP, a loose convertor, sticky tires etc,,, it's not going to be much matter.,, then go for load distribution and ride.

[Pyrotechnic]

Thank you for the help and comments! Just wanting to make sure I'm on the track before I start making these changes.

The truck has a 383 with 10.5:1 compression, 200cc aluminum heads, roller cam, etc. Should be around 450HP at the crank. Trans is a Turbo 350 with a converter that flashes to about 3500 with the current gears. The rear gears are 3.08 and an auburn posi but hopefully down the road they will be switched to something more desirable. I have some 15x10 wheels with 325/50/15 drag radials for track use.

Hoping to break in to the high 12's at least.

Would the weight of the battery be more effective in the place where I have the jack located? The jack wont be there at the track so that spot is fair game. It will probably be much easier to get the battery in and out in that spot if it will fit.

[GMR-PERFORMANCE]

A bit of info on battery. Even glass matt AMG style you should mount so that the edge of the plates are with the g force of the launch. ASK me how I know.... I had the plates bend and short out. ( battery long ways across the bed ) Does that make sense ??
A battery fire is nasty and makes a huge mess.... You have it correct in the pic, JUSt a FYI

[Pyrotechnic]

Originally Posted by GMR-PERFORMANCE

A bit of info on battery. Even glass matt AMG style you should mount so that the edge of the plates are with the g force of the launch. ASK me how I know.... I had the plates bend and short out. ( battery long ways across the bed ) Does that make sense ??
A battery fire is nasty and makes a huge mess.... You have it correct in the pic, JUSt a FYI

Whoa that is good info, thank you. I have an AGM style battery, but the plates are actually set up like a lead acid battery...not the orbital style you see from Optima.

Just so I know what you mean here, the g forces are pushing back when you launch. These rearward forces need to act on the battery in such a way that the they hit the thin edge of the plate, rather than hitting the plate on it's large side?

A battery fire does not sound good at all and it really doesn't look good how I have it next to the fuel cell. I know people mount them next to the fuel cell in the trunk all the time though. Would a solid metal box with a vent tube be enough to prevent a fire from starting? What about a plastic box? I'm thinking a well sealed box and a vent tube should relieve pressure but prevent oxygen from fueling the fire. I had planned to run a box no matter what to keep the battery out of the road grime.

[GMR-PERFORMANCE]

Yes you have it correct. Thin edge front to back. The plate is not supported on the bottom from what I am told. Thus that large surface area bends a bit every time you launch the truck. Then it makes contact with the next plate.. Hence kinda like laying a 3/4 wrench arcoss both terminals and waiting to see what happens.. As far as the battery box goes I like the metal box style myself.