Why do ebay listings for torsion bars designate small block or big block only?

[Dibbons]

Never changed a torsion bar, but I am thinking about upgrading. I was confused looking at bars on Ebay that show different(?) bars for big block and small block. I assumed the B Body chassis structure was the same for either motor. Is there a difference in torsion bar mounts between the two motors. I have a 1972 SSP. Thank you.

 

[ODZKing]

71-2 Sat from Collision manual

 

[Dibbons]

PST on ebay lists two different BBody 1.03 " diameter torsion bars that have different part numbers but the same price: TOR4830 and TOR4830 BB. That is my confusion. The first one is listed for small block only and the second for big block only but they are the same advertised diameter.

Problem solved
Answer from Ebay:
There is no difference. Our old design bars used to differ between small and big block but these new bars will work for all engines. It was just easier to leave the listings up on EBay rather than remove them. Sorry for the confusion.

 

[d fark]

The only difference I know is 73 and up uses a longer 43" bar.

 

[ODZKing]

The only difference I know is 73 and up uses a longer 43" bar.

That is definitely true. And even with that there are different thicknesses.

 

[YY1]

Yep Different.

Different thickness.

Although I find it hard to believe that chart that seems to say all station wagons used the same bars as 6 cyl cars.

 

[dangina]

are you replacing shocks as well? don't be afraid of larger torsion bars, check this out:

http://board.moparts.org/ubbthreads...in-shocks-over-1-0-bars-kybs.html#Post1815129

 

[Nacho-RT74]

Small Block T bars are on .82" to .90" thickness rate.

Big Block are from that up to .96" or even 1" thick on C bodies.

is all about the spring rate to hold the engine weight.

The shorter the bar, less thickness required to hold same weight... this is considered to the body lenght. This is because longer bars gets the torsion shared over more surface all allong the bar

 

[Bruzilla]

The other thing to keep in mind is that the original bars were meant for engines with original horsepower ratings. Many engines today exceed what they had coming from the factory, which is why you should use a 1" or bigger bar.

 

[YY1]

...and of course there's the drag racing weight transfer crowd that puts 6 cyl bars on big block cars.