I am thinking of putting a 66 Hemi into my 67 GTX. Do you think it would be ok to use the existing torsion bars or should I upgrade to Hemi torsion bars. Its going to be a restored driver car. I think there
are ones for 440 and ones for hemi? Thanks.

The original 318 torsion bars are holding up the Hemi in my mostly street Cuda. Been that way for years. Try the ones you have. If there is something about them that you don't like, it is no big deal to change them later.

Thanks.. that is true..

With aluminum heads, intake and water pump housing the Hemi probably would weigh less than your 440.

If it's a GTX it should already have stout factory bars in it capable of "supporting" the HEMI, but if they're tired 50+ year old bars, now's the time for an upgrade in suspension and braking IMHO as well as a freshening of the front end components, and if you have an anemic 8 3/4 trailing out back, a Dana 60 is your best friend behind a HEMI...

It all depends on how you are going to drive the car. If it is a show poodle then who cares, the torsion bars just hold it up in the air. If you are actually going to unleash the Hemi once in a while then now would be a good time to upgrade the suspension and brakes. If it was me I'd put larger than stock torsion bars on there as well as disc brakes and high quality shocks. But if you're just going to cruise over to the burger joint on Saturday night then save your money and use it on some chrome valve covers.

After swapping to a Hemi in my road runner with the stock 383 suspension, my leaf springs that used to be 'C' shaped are now 'S' shaped...

It managed to bend them despite using repop Goodyear Polyglas GT F60-15 bias ply's!

To me, running a musclecar on fifty year old springs makes no sense at all. Unless you are racing, small torsion bars do you no favors at all. I switched both of my cars over to the 1.03 performance bars and had no degradation of ride quality, but Man! what a difference in handling. Six of my friends were so impressed by the difference, that they changed over also and love them. Best $200 I ever spent. Biggest felt improvement for dollar spent.

The 440 and Hemi bars are the same. Those 50 year old bars are most likely made of better steel than the aftermarket stuff available now. Some of you guys seem to think as soon as you drop the Hemi in the original T-bars are going to snap into pieces. This isn't GM crap.

Agree. I've found rear leaf springs to sag and get weak over time, but not the same with torsion bars. I had both torsion bars break on a 57 Plymouth I had when I was in HS, but no problem at all with any of my later cars, and I have around 70 combined owner years with 64 Plymouths plus 11 more with E-bodies. Replaced rear leaf springs on all those cars, but never a torsion bar.