From Rootes Review
Vol. 3, #2, March/April 1978

by Bernard Clarke
The Sunbeam Tiger Owners Club

Appeared First in The Cats Whiskers, Issues 2 and 3
The Club Publication of The Sunbeam Tiger Owners Club, England

In common with many Tiger owners, I found after owning the car of my dreams for a few years, that I was treating with contempt the power which earlier had sent the blood coursing through my veins. Why is it so sluggish? I kept asking myself. The answer, of course, is that I had just become accustomed to the power. The trouble with the power chase is that the more you’ve got the more you want, so the logical solution was an engine rebuild plus some bolt on and in goodies to release more horses. Well, while we’re taking the lump out, might as well drop a 289 mill in, should fit O.K.

So off I went to secure a secondhand ex-Mustang 289. I spent three months rebuilding and modifying, then found the first snag-the 260 has a five bolt bellhousing and the 289 a six bolt. So I needed a new bellhousing, and when that arrived so did the second snag-the standard six bolt housing doesn’t fit the 260 gearbox. That meant making an adapter plate, and whilst making an adapter for the 260 box it would be almost as easy to make one for a box with an overdrive. I had always wanted overdrive anyway and since the original box can’t be modified, it meant going to a different box. So the next problem was to decide on a suitable unit that could cope with the power and more importantly the large torque of the V8. A quick survey of available and suitable boxes soon narrows the choice down and by the time you’ve ruled out the £200 plus jobs, you’re left with the Jaguar cogs. The one I finally selected was the all synchro 3.8 MKII Jaguar unit. After a few nasty experiences I eventually located a box in good nick.

Well that is a summary of how I decided to fit the Jag box. The advantages of overdrive are fairly obvious to all of you who own Tigers, for cruising such a light car and big engine at say 80 to 90 mph it’s not necessary for the engine to be doing over 3,500 rpm, when the 2,800 which overdrive gives is quite ample, and if acceleration is required at these speeds, it is instantly available at the flick of a switch. The overdrive, in fact gives 30 mph per 1,000 rpm, which gives a top speed of 150 plus mph should you require it. Also, hopefully, more economy and less engine wear. The overdrive has behaved faultlessly for nearly two years now and was a thoroughly worthwhile venture.

I decided to use the 289 light weight flywheel and 10 1/2″ heavy duty pressure plate, the Hays unit would be better but at £90 plus against the Hi-Po unit at £23, the latter had to be. The big problem was the clutch plate, it must be 10 1/2″, mate with the Jag box splines and be capable of taking V8 torque. The Jaguar unit was too small and wouldn’t take the torque. A few ‘phone calls to Borg & Beck later, and I had the answer-the Range Rover plate would work and it was fitted with B. & B.’s best lining material.

Using the 289 – 6 bolt bellhousing the next job was to make an adapter plate to mate to the Jag box. This was made out of 3/4″ aluminum plate, and when made and bolted together looked really fine.

The next problem was the overdrive unit. I decided it would be a good idea to recondition it before installing in the car, so I went to G.H. Nolan’s, the Jaguar specialists in South London, to get some parts. I saw Mr. Nolan himself and explained what I intended to do, he then assured me that the o/d would break down under the torque-great! Just what I needed at this stage. Then he kindly showed me a dragster they were building with a fuel injected V12 fitted, would you believe, with one gear and overdrive. Mr. Nolan said one or two mods had been necessary but they were pretty confident about it, and sure he could fit me up with the uprated parts for my unit. So I ended up with a high volume pump to provide more pressure, stronger return springs and a new cone clutch.

That brought me to the last item in the drive transmission to be modified, the propshaft. The Jag shaft fits the Tiger back axle, but is too long, so a section was removed and welded to shorten it, a comparatively simple job.

Luckily the speedo drive ratio is the same on the Jag box as the Tiger, a small adapter soon had the speedo fitted up and working accurately.

All that was left to do now was to insert this assembled lump into the car. Using a friend’s garage in which we had dug a pit, we took the old 260 lump out by dropping it through the bottom of the car into the pit-by far the easiest route for removal. The Jag box is taller than the 260, and because of the o/d, is fatter at the rear end, so this necessitated major surgery involving cutting out the old tunnel cover over the gearbox and making a new one which was made removable for access to clutch, gearbox and o/d. The old rear gearbox mounting plate was cut out and a new one made up. After some cutting and shutting and many hours down the pit, which would take on 6″ of water every time it rained, the whole thing was installed and looked very smart. The gear lever was in just the right place and I mounted the o/d switch on the left of the steering column in the hole provided for the Alpine o/d switch.

The o/d is really smooth in operation and an invaluable driving aid. The Jag box, though a little bit notchy and not ultra rapid, which is inevitable for such a strong box, is much more precise and positive than the old HEH box.

Though the project was a big hassle at the time, it has been thoroughly worthwhile and is the envy of most Tiger owners after they have had a drive.

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