whatt would it take to get my truck into the low 12's
 

i am building a 72 swb stepside, 402 bb, prob a turbo 350 built right, floor shfter, at least 4:11's and posi,fuel cell in rear, will 450 hp and slicks get me there, prob not huh, i was thinking weight reduation at first, just to run it when i'm finished, maybe without a bed, but now yall say to put weight in the bed to hookup, what setup do any of yall have that run those kinda times, i'm getting ready to start on suspensoin, so i need to figure out this stuff now, thaks guys, sean also will the drop kit affect times, i am installing an Early Clssioc 4/6 drop kit, i wod think it would make it handle alot better

[This message has been edited by seanh71 (edited May 14, 2002).]

First I would try to move as much weight as possible to the rear of the truck. Things like the battery and the fuel tank should be behind the rear axle. If buy chance got got this thing to hook your stock rearend would probaby be toast before the run was over. I would want a narrowed 9" so you could put some serious meat on the back. If you have trailing arms they could probaby be modified to hook up. When you get the traction worked out put the truck on a diet,anythind you don't need,like a/c,heater,etc needs to go. When you get the traction issues worked out,then it is time to pump up the horsepower,if low 12's are your game I wouldn't think of building anything smaller than a 468. Speed costs money,how fast do you want to go?

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

almost makes me want to drop the 402 into a s 10 or somethin, to take care of the stangs and honda crap, damn, guess i'll have to go with nitrous, this project is getting more and more expensive and i havent really started yet

if you put the engine on the 6 banger mounts it will move a little of the weight towards the rear, a 450 horse small block with a small hit of juice, maybe in second gear and threw the traps, will make it into the 12s. the 12 bolt...in good shape can handle some 10 inch slicks..enuff to get some decent 60 foot times...you have to remember your trying to push a garage door down the track at 108 MPH...if you want to see a great example of a rear set up..look at 68prosteet's web site it is truly sweet, im so jealous

whats his wbsite address? isnt his a f@rd 9 inch though, i already have a 12 bolt and a dana 60, too muchwork involved in the 9 inch

The 402 in an s10 is probaby a better plan, but you are not likey to ever see low 12's in any pickup without some serious rear modifications. Trucks just don't get no traction

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

http://www.samracing.com/71_chevy_c10.htm

that's a truck that runs in the 12's

I have been bracket racing my 68 lwb truck this year 383 c.i., 4.57 gears, drag radials,it has a 4/3 drop springs and shocks and a stock coil spring rearend best so far is 13.14 and a 60 foot of 1.75 I have been amazed at how well it hooks.

I went to his website,huh if I had run mid 12's I would sure post a timeslip, didn't seem to be one on the website. I never seen a 3800 pound brick run 12's on radial tires ether. Sorry I need more proof than that. Nice truck tho. LOL

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

i dont know much about that stuff but it doesnt look to me that that truck is running mid 12s. especially on tires like that. and doesnt say anthing about rear susp upgrades either.

What little I've learned from racing a Buick GN -
If you have coil springs in the back (showing my ignorance here) install air bags - at least on the passenger side.
Put a level on your rear bumper and have a buddy watch it while you push on the brake and the gas at the same time.
Play around with the air pressure until the level is - level. That should pre-load the right rear.
I know a guy who has a tubbed out '72 that runs 11's. If you have some questions, I can ask him how he does it.
Bet it involves $. http://67-72chevytrucks.com/board/ubbhtml/smile.gif

I disagree with the assumption that it's nearly impossible to go 12s in a 67-72. I have a buddy at the dragstrip with a 71-72 SWB that is running mid to high 12s with an original interior and A/C. The truck is running a 454, tubbed in the rear with some Koni coilovers that replace the stock coils. (they're welded to the axle tubes.) Voila, 12's. One of the coolest things about this truck is the stock style rally wheels that are widened to 15" out back. Totally slick.

-Jeff

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69 LWB C-10
67 SWB C-10
92 K1500 'Burban

i think what someone else and i was saying is that its probably not going to happen with out hooking up. the truck that runs 12.58 has some regular radials on it. your buddys truck sounds like it has some rear susp work.

i had a 97 s10 with a 4.3 and did all the lil bolt ons. ran a 16.1, i put on some some big meat on the back and the truck would barely spin the tires, knocked it down to 15.7 the next time i went. i think traction is the easiest way to get faster times. ones your truck hooks then start doing other stuff

Nope, the only rear suspenison mod was the coilover shocks. Adjustable that is. He can set them real soft so that the rear end squats and in turn plants the huge slicks real hard. I was amazed, to say the least.



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-Jeff

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"You might be a REDNECK if someone yells 'Hoedown' and your girlfriend hits the floor"
-Jeff Foxworthy

'69 C-10 LWB (hot rod)
'67 C-10 SWB (hot rod in progress)
'92 K1500 'Burban (daily driver/tow vehicle)

Actually, when the torque is transmitted to the rear end, you dont want your vehicle to squat. The vehicle squatting is putting less pressure on the slicks than a vehicle who's rear end shoots up at torque time. If you have say a 4-link, or even the stock leafs, you have an instant center line from your leaf spring eyelet mount, and you have an imaginary nuetral center line on your chassis. If your instant center is above your neutral line, then your vehicle will raise in the rear, giving you optimum traction. And if your instant center is below your neutral line (most common), your vehicle will squat, which is actually your rear end trying to leave the ground, since it cannot, the suspension squats. When the rear end raises on a launch, you are putting maximum planting force to the rear end for the best traction. looks can be decieving...

Seems that everybody that knows sombody who's truck run's a desent time keeps saying the word tubbed.LOL

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

This truck runs 12's on the motor and 11.60's with the squirt. It is an Edelbrock headed Pontiac 455. It can be done, but the weight is a killer.
http://209.198.134.122/photos/grntrk.jpg
In a 2600# car, 350 RW HP will get you in the low 11's. In a 4000# vehicle, figure low 13's or possibly high 12's. Check out http://www.hybridz.org/ubb/ultimateb...;f=13;t=000247 for a weight/power discussion.

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70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

I think the rule of thumb is for every 100lbs you lose...is worth a tenth...hmmm..i can stand to lose about 50lbs myself... Theres .05..

Hey guys, the F@rd 9 inch isn't really that difficult of an install. Any good parts store can match you up a univeral joint that has the 9 inch on one side and the stock driveshaft on the other. Plus if you get the right year rear, it will even have the same 5 on 5 bolt pattern. Once I get mine driveable and make a few runs, don't be suprised to see a ladder bar or link setup in place of those chrome leafs.

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Prost68trk web page
or btshaffer@wmconnect.com
'68 short/wide, 402BB/TH400, '81 rear frame rails, F@rd 9" 31 spline, leaf springs moved inboard, shaved firewall, cab seam, wiper cowl, dash, hood ridge, chrome drivetrain.
'97 Z-71 Ext-cab Driver
West Fork, Arkansas
IM - btshaffer (will soon change)

Prestage.com computes a 3800lb "Brick" will take about 586 hp to break into the 11's. That's some healthy pop!

Yea but the it does not compute traction. Nobody has said it is impossible to make a 67-72 run any thing. IT is possible,if you throw enough money at it. The reason I keep bringing up the negative points is I want people to think long and hard before trying to do it. If you want to go drag racing, a 67-72 truck is not the vehicle to start with unless you are crazy. They are too heavy,all that weight is on the front,and they have no areodynamics. It is kinda like trying to teach a pro wrestler to be a ballerina,he could do it,but the skinny girl would always be better at it. The only reason to have a 67-72 chevy truck at a dragstrip is to pull the trailer that your drag car is on. LOL

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72 GMC Sierra SWB almost finished---- 84 Softail
Olive Branch MS

I have a Pontiac 455 for sale!

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Charles W. Hein
S. Williamsport PA

imaindianoutlaw@yahoo.com

REFRIGERATION TECH

1971 Rolling chassis

FOR SALE
1963 Pontiac Tempest
1965 Pontiac GTO
1956 Pontiac 2 dr

Good points Tom. While I agree you probably won't be a class champ every weekend at the strip with a 67-72, a guy could sure but a pain in the @$$ to those who are trying. Sure they are big square boxes, but thats what its all about! Anyone can take a small, aerodynamic ride and make it go fast but not many can do it with a big square box. I don't think a guy would have to be "crazy" to drag race a 67-72 truck, unless your talking about his "crazy passion for the style.

Blue Pig,

I'm having a hard time grasping what you are saying. Traction is all about weight transfer. The more weight you can transfer to the rear at launch, the better. This is the reason for 90/10 drag shocks. The let the front rise quickly and the rear end squat and keep them there for awhile. Traction is directly proportional to your coefficient of static (and dynamic) friction and the normal force on the rear wheels. The best launch you could ever have would see your front wheels SLIGHTLY off of the ground. This will give 100% of the vehicle's weight applied to the rear wheels, without wasting kinetic energy by lifting the front wheels way up. This is also why the old "gasser" type cars with the solid front axle were so tall in front, because the weight transfer was easier. Gosh, I knew that dynamics class was good for something!!



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-Jeff

-------------------------
"You might be a REDNECK if someone yells 'Hoedown' and your girlfriend hits the floor"
-Jeff Foxworthy

'69 C-10 LWB (hot rod)
'67 C-10 SWB (hot rod in progress)
'92 K1500 'Burban (daily driver/tow vehicle)

Put a Mopar engine in it...LOL