Finally found a Merkur IRS pic.
As expected it is very similar to the T-Bird IRS but a bit smaller and lighter.
58" stock track so it would still have to be narrowed for most of our cars.
Same sort of mods used for the T-Bird should work for it.
Very popular in England, companies there sell bolt in conversions for MG's.
Apparently good for about 300+ HP in light cars.
159345390_merkur-ford-scorpio-xr4ti-hubs-differential-rear-end.jpg
Is that what the Hoyle kit uses?
Yep, Larry Shimp upgraded his with Dutchman's axles.
http://www.britishv8.org/Articles/Hoyle-IRS-Anti-Sway.htm
I am disappointed that the only units I can find reasonably close have drum brakes.
Looks like the U.S. version was cheapened.
But that can be upgraded later, first I want to get a rear into my car.
I found a guy in England who was making a kit to fit Merkur rear's into GT6's!
He did a few then suddenly stopped posting about it.
Seems he wrecked his personal GT6 during a night rally on the continent.
I've emailed him to see if I can work out a way to get a set of his drawing$ or possibly one of his built unit$,
The Hoyle kit only uses the Merkur/Sierra differential, CV joints, brakes and hubs. The rest is made by Hoyle. It has upper and lower A arms with coil overs, and everything is fitted to a custom tubular frame that bolts to the original MGB lever shock mountings, bump strap mounting, and front spring eye mounting. Also, be aware that there are small and medium size differentials. The small ones only work for 4 cylinder cars and will not hold up to a healthy V8. The larger units are used with V6 and turbo cars. Probably not a problem if the differential comes from a US market car but if ordered from overseas this becomes important.
I'm disappointed the fellow who was doing GT6 conversions has not replied.
Found some Merkur units, ex 2.3 Turbo, but have not been able to buy one yet.