That head sounds perfect for a supercharged motor, with a little exhaust porting. I'd buy it just for the historic value! The Repco/Brabham team were pretty innovative. They even produced racing heads for the B20 I am told. I will take the head, I'll let you know when I'm coming down next. I'm stuck renovating my bathroom at the moment, I can't walk away from that and live.
That Toyota 4AGZE supercharger is probably a SC-14, if it is I have some data on it, as follows: See ya, Matt

Toyota SC-14 Supercharger
Description and Operation
Both of these superchargers are roots-type positive displacement superchargers.
The rotors are fluorine resin coated. The units have their own lubricating oil, 130cc. Stock boost is regulated to about 0.7 bar, and the units are normally driven at 1.25 times crank speed (4A-GZE has a 7500rpm redline). Oversize pulleys are available.
The Toyota 4-AGZE motor was used in the 86-89 MR2 Supercharged edition MR2s. The motor is a modified 4-AGE unit coupled to an electronically engaged roots type supercharger manufacturer currently unverified and a Nippon Denso air-to-air intercooler. Static compression ratio of the motor was dropped from 9.4:1 to 8.0:1. The camshafts are identical to a normally aspirated car, although their timing may be different. The motor is fitted with a different type of injector with a higher flow capacity. Boost level is set at 8 PSI and achieved at 4000 RPM and higher, however the supercharger creates usable boost from idle through redline.
The supercharger is driven by a serpentine belt off of the crankshaft and shares its drive belt with the water pump.
The supercharger adds heat to the intake charge both by conduction of heat since the supercharger is bolted onto the engine and also by pressurizing the intake charge. With the bypass valve open and the supercharger disengaged the intake system raises the intake charge temperature by about 30 degrees F once everything is up to operating temperature. Running under full boost with an outside air temperature of 50 degrees F the air temperature of the SC outlet can get as high as 270 degrees.
Vent holes are placed at three points in the housing. One in the rear gear housing and one to each of the shaft ends of the vanes on the front of the supercharger. The vents are all connected together via external metal tubes and hosing. An air valve is connected to all the vents, which can purge them to the intake system after the airflow meter but before the throttle body.
Supercharger Clutch
The supercharger clutch works in the same way as an air conditioning compressor clutch. The pulley itself spins freely on the supercharger-input shaft. A coil of wire sits behind the pulley and a metal disc sits in front. The front disc is connected to the actual input shaft of the supercharger. When the coil is energized, the disc is drawn against the rotating pulley and they then rotate together as a unit until the coil is de-energized.
The manufacturer intended this clutch to be operated based on intake manifold vacuum. If vacuum drops below 8"Hg the supercharger clutch is engaged. The clutch should stay on until the intake manifold vacuum has risen to over 10"Hg for a period of 5 seconds. This time delay is required to avoid cycling of the clutch during shifts and momentary throttle transitions. A delay circuit is required to replicate this behaviour when fitting these units to other vehicles
The manifold vacuum during highway driving will be low enough that the clutch will stay engaged all the time with an appropriate controller circuit of this type
Physical and Functional Data
Type Year Model Length Width Height Weight = Displacement
SC14 85-89+ 1G-GZE 311mm 148mm 254mm 11.9kg = 1420cc
SC12 86-89+ 4A-GZE ~249 148 254mm 10.8kg = 1200cc


Maintenance Data
Supercharger bearings
For the small bearing (shorter shaft, sealed only one side)
Koyo part number: 03NU0514-7
Inner diam: 0.668"
Outer diam: 1,772"
Thickness: 0.548"
For the thicker one, sealed both sides
Number unreadable, but seal number 03NU0518-2 (the "8" is a guess)
Same inner and outer diameter,
Thickness: 0.705"
10,000rpm +
Lubricant
The gears are run in Toyota supercharger oil, Toyota part number 08885-80108. Total gear housing capacity is 130ml. Other types of lubricants may work satisfactorily. It is not unreasonable to expect a decent hypoid gear oil to work. A 90-weight synthetic gear oil appears to be the closest commonly available equivalent.


Disassembly
Two special tools are required for disassembly of the supercharger; SST 09504-00011 for keeping the pulley from rotating while you undo the nut that holds the clutch hub to the supercharger. If you have an impact wrench you might be able to get by without this for removal. However you will still need something to hold the pulley when you tighten the nut down upon re-assembly. SST 09814-22010 for removing the ring nut that holds the clutch pulley on. You can't get by without this short of having a set of ring nut sockets or custom building the equivalent tool.