Up grading from small block to big block, Should torsion bars be upgraded also?

[Back N Black]

 I think the 383 is 150 lb. heavier than a 318. Not looking for performance upgrade, just don't want the front end bottom out.

[Mike DC]

If you have stock T-bars?  Yeah, put bigger ones in there. 

I prefer soft corner springs on cars in general.  But the front T-bars came a little too soft from the factory, everybody agrees on that now.  (BTW, the staggered rear leaf springs on factory R/Ts were NOT too soft.  They were arguably too stiff, if anything.) 


B-body torsion bar sizing: 
The stiffness of a torsion bar goes up dramatically as it gets bigger.  It doesn't take twice the bar diameter to get twice the stiffness.    

stock base Coronet (slant/318):   0.88
stock base Charger (318/383):    0.90
stock R/T (440/Hemi):                0.92

Today they make sizes like  0.96, 0.98, 1.00, 1.03, etc.  Those are good street choices. 

Some guys go stiffer but I'm not a fan of that on a street car.  Stiffer chassis springs are like bigger camshafts.  It's good in moderation, but there is a tendency to overdo it.   

[Back N Black]

If you have stock T-bars?  Yeah, put bigger ones in there. 

I prefer soft corner springs on cars in general.  But the front T-bars came a little too soft from the factory, everybody agrees on that now.  (BTW, the staggered rear leaf springs on factory R/Ts were NOT too soft.  They were arguably too stiff, if anything.) 


B-body torsion bar sizing: 
The stiffness of a torsion bar goes up dramatically as it gets bigger.  It doesn't take twice the bar diameter to get twice the stiffness.    

stock base Coronet (slant/318):   0.88
stock base Charger (318/383):    0.90
stock R/T (440/Hemi):                0.92

Today they make sizes like  0.96, 0.98, 1.00, 1.03, etc.  Those are good street choices. 

Some guys go stiffer but I'm not a fan of that on a street car.  Stiffer chassis springs are like bigger camshafts.  It's good in moderation, but there is a tendency to overdo it.   

Thanks, great info.