To Tub or Not to Tub

[dnrnflcpl469]

I have a question: first of all i have a 73 nova bb 402 automatic 3 sp hurst shifter 3400 stahl convertor, im not sure which gears i have in the rear on person says i have 373,the next person says 411,i have 28.14r15 wheels now .heres the questions A.how do i check which gears do i have B. what size tires do i want to use for the best run C. should i tub the tires and how will that hurt or help performance.D. the tires i have now stick out about 2.5 inches from the side of car and the car will smoke them in all three gears all day long this is cool but im intrested in speed and the best results on race day what should i look for and what do u think.

[DCarr511]

Originally Posted by dnrnflcpl469

I have a question: first of all i have a 73 nova bb 402 automatic 3 sp hurst shifter 3400 stahl convertor, im not sure which gears i have in the rear on person says i have 373,the next person says 411,i have 28.14r15 wheels now .heres the questions A.how do i check which gears do i have B. what size tires do i want to use for the best run C. should i tub the tires and how will that hurt or help performance.D. the tires i have now stick out about 2.5 inches from the side of car and the car will smoke them in all three gears all day long this is cool but im intrested in speed and the best results on race day what should i look for and what do u think.

A) If you have a LSD ( posi ) jack the rear up and support the car, mark the tire and the driveshaft. Turn the tire one full rotation slowly while counting how many rotations the driveshaft makes. This will get you real close ie: if the driveshaft turns just short of 4 tunrs then its safe to say you have 3.73's if its just barely over 4 turns then its most likely 4.10's as GM didnt offer to many cars ( if any ?? ) with 4.11's.

If its not a posi then do it the same way except turn it by the driveshaft instead of the tire.

B) Its not just the tire size that matters, the compound of the tire has an affect also along with suspension work. And if its on the streets only and no track use .. forget about it and buy the cheapest tires you can. Nothing will hook. If it is raced at the track also then you want the tallest tire you can fit in it and go from there.

C) Tubbing or " Backhalfing " the car is entirely up to you. But it is NO garauntee that it will cure it. And you can plan on spending about 5k + or so. If you TRUELY want the car to hook up then it will take front and rear suspension work which will affect the comfort of the ride on the streets. Have to make a decision yourself as to what you really want.

Bottom line is there is NO majic answer

[dnrnflcpl469]

Thank u for replying !! ok i understand now how to check the gear raio. also the car is posi traction. i curently have micky thompson sportsmans tires on it that are street legal . my only thought for tubbing the tires was to get the rear end to squat down as low as possible . the car is being set up for the sportsmans clas NHRA with the idea in mind for possible pro sport ? I just wasent sure if i should go to the expense of tubbing or i could cut and reshape the fender well as i am a sheet metal man and could easily do this .i was thinking of using the good year eagle slicks 31x14 r15 slicks maby a 32 " i dont know

Originally Posted by DCarr511

A) If you have a LSD ( posi ) jack the rear up and support the car, mark the tire and the driveshaft. Turn the tire one full rotation slowly while counting how many rotations the driveshaft makes. This will get you real close ie: if the driveshaft turns just short of 4 tunrs then its safe to say you have 3.73's if its just barely over 4 turns then its most likely 4.10's as GM didnt offer to many cars ( if any ?? ) with 4.11's.

If its not a posi then do it the same way except turn it by the driveshaft instead of the tire.

B) Its not just the tire size that matters, the compound of the tire has an affect also along with suspension work. And if its on the streets only and no track use .. forget about it and buy the cheapest tires you can. Nothing will hook. If it is raced at the track also then you want the tallest tire you can fit in it and go from there.

C) Tubbing or " Backhalfing " the car is entirely up to you. But it is NO garauntee that it will cure it. And you can plan on spending about 5k + or so. If you TRUELY want the car to hook up then it will take front and rear suspension work which will affect the comfort of the ride on the streets. Have to make a decision yourself as to what you really want.

Bottom line is there is NO majic answer

[500]

Unless you just love your Nova I would not spend the money to tub it because you will never recoup even a fraction of the cost when it comes time to sell. Find a late model car and tub that. Lots better resale value.

[dnrnflcpl469]

thank you for your reply 500. we really need to know if tubbing gives you any benefit as far as the race track goes (forgetting the money side of it) this car will probably never be street legal again. we think its to far for that.

[DCarr511]

Backhalfing the car will allow you to have a lower ride height and shorter axles which are both a plus.

Then you get to decide if you want a 4 link or Ladder Bar. In 99% of cases a ladder bar is all a car needs. And as Dave Morgan says in his Doorslammers Chassis Book referring to 4 links " Misery loves alot of Chassis Holes ".

4 links arent real bad to set up if you plot them out from the start, figure out where it should be set up and left alone.

Good luck with whatever you choose.


Duane

[nissanfanatic]

There is software that can tell you exactly how to set up your 4-link.

I say LSD and some drag radials. Should do what you want easily. Plus tubbing=way too much money for the result. I'd do a line-lock+2step then some drag radials on as wide of rims as you can. See how that does.