[olddog]

I'll start with my understanding of the subject, and let you all tell me where I'm wrong. I need some education.

IRS will give better handling and ride, if only theoretically, but this seems to be accepted by most. Many manufactures offer straight axles, especially the 9" Ford. Certainly they can work. The very short (approximately a foot) drive shaft limits the allowable travel on a straight axle, which can affect handling and ride. Maybe this is true, but in a practical sense, does it matter?

If you go straight axle there is three link and 4 link and maybe more. Handling issues that I'm certain that I do not understand. I do know that a 9" is plenty strong for 500 lb-ft of engine torque and sticky tires.

IRS - most manufactures who offer these use the T-bird 8.8" setup. A FFR guy at the London show stated to me that with street tires the HP does not matter, as you cannot put more to the ground than the 8.8" IRS can handle. I don't buy that argument, as I put a 283 with turbo 350 automatic in a Vega, leaving the Vega rear end and stock tires on it, with the same reasoning. First time it shifted from 1st to 2nd at full throttle the rear end disintegrated, and the engine over revved and spun a bunch of bearings. Chock it up to youth.

The Jaguar IRS is used by a few and is plenty strong, but a pain in the butt to work on. At least that is the claim. Mercedes, and Vettes have better IRS on them, but I hear little about them. I don't know why you couldn't cut a 9” down and make an IRS out of it. What options are there on IRS?

Is there any info on how much torque the different IRS options can handle? Any practical information on the ride and handling advantages on the IRS?

Thanks in advance.