MG Car Repair: SD1 gearbox, triumph tr 7, mgb gt

Question
I'm preparing to convert my 1980 MGB using a Rover SD1 V8 & 5-speed gearbox.  Roger Williams' book tells me a transmission tunnel modification is necessary.  Are you familiar with this modification, and if so, can you tell me if it causes problems for the heater controls in the center console?

Thanks,
Billy

Answer
Hi Billy,
I have some experience with the Triumph TR-7 5-speed box (as I understand it is the same as the Rover 5-speed box)

As far as needed modification to the tunnel, it depends on what engine you plan to use and the engine location. Also what bellhousing are you going to use.

I have a MGB GT that I am converting but I went radical with a 215 Olds V-8 (About the same block as the rover 3500 engine) and I am using the TR-7 5-speed box (Rover 5-speed).

It may not have taken much if any modification to the tunnel for my installation except I wanted my engine to be mounted further back and down as compared to the standard installation. This forced me to modify the shift tower on the box to get the shift lever in the same location as the MGB lever was. To get the engine back (the 215 is longer than a B engine) I removed the shelf that the heater sits on.
You didn't say which engine you are using so I can't think of what possible problems you are going to run into.

If you are going to use the 215 Rover bellhousing, it is larger in the upper flywheel area and some heavy hammering will probably be necessary at that point, unless you want to cut and weld in sheet metal.

If you are installing the Rover 215 engine and mounting it forward like most do, it probably will only be some minor hammering at the upper bellhousing area.

If you are going to use the original shifter location you can use that as a base line and do all of your measurements from that point.
I was luckier than most in that I have an extra 215 empty block, so it was easier for me to do the many fit-checks. My standard joke was that I did so many fit-checks that I wore our several sets of bolts putting it in and taking it out. I envoy those who only do one or two fit-checks.

I documented my installation on my website and you are welcome to read it. I don't know that it will help you on your installation or not. http://mg-tri-jag.net/Pictor2.htm is the firewall/bellhousing area I am referring to. The picture is of a B roadster not my GT but they are the same in that area.

I hope this helps,
Howard