Harry Firth The XR GT and I “W
Before his passing in 2014, Harry Firth penned his recollections on the XR GT for the Ford and I oneshot magazine. Here Harry recalls his demon Bathurst 1967 tweaks and outlines his vivid recollections of how the race panned out.
ork on the new XR GT was in progress as early as 1965. My role was developing a ‘police special’ as suitable camouflage – Vic police light blue and very stark trim and no embellishments such as chrome wheel trim and exotic dash. The economics of this was very simple: 1000 GTs only would be expensive to make and would tie up a production line. But add to that base build another 2000 police specials and costs go way down. This is how the XR GT was put on the market at a very reasonable price. An automatic version was run in the BP Rally and the Surfers Paradise 4 Hour race for series production cars. It led the Surfers race in the dry, but fell back to second in pouring rain. Being the driver, it was easy to put the lessons from this into the XR GT design. I also did testing on You Yangs proving ground, using the 70,000 mile test circuit, which was very similar to Bathurst – so the suspension, brakes and handling were completely race and rally tested. The prototype went around in two minutes 39.5 seconds against the 200 cubic inch coupe’s time of 2m44.3s. It did 124mph down the road outside ground, so it was a reasonably developed race package in 1966 to early ’67.
“But some things that should have been easy proved difficult. For instance, at You Yangs I was testing the prototype XR GT and one of the rubber locators for the front sway bar came out – they didn’t have any restraining clips. So, no sway bar, and I spun it down the hill at about 120mph. Not good! I told the Ford engineer and he said: ‘nah, couldn’t happen!’ All it needed was a small strip of steel to stop it coming out, but the engineer refused to accept this. A month later, he’s driving one himself out on a highway, and a rubber sway bar mount flew out, and he lost it! Very red faced, but they did put clips on it after
that! Very simple, but these people could be very dogmatic at times.
“Of course, there was no testing allowed at Bathurst as it was a public road. However, a few did the occasional moonlight flit at two in morning and be long gone before police could make it to the mountain. Serious offenders didn’t use Conrod Straight as you could do that on any main road. If you did this on race weekend, the flaggies camped on McPhillamy kept the soapy shower and washup water in four gallon drums on the side of circuit and would spread this on the drift line for constant offenders. It produced hilarious midnight gyrations but never a serious bend…
“The thing is that you’ve got to be able to stop. That is what held back the old Studebakers and other V8s at Bathurst, but they had other problems too, like general unreliability and terrible handling – they were not good cars – and I made sure that that was not going to be a problem for us with the XR GT.
“Anyone running an XR GT who elected to do their own preparation and not be advised by us was making a serious mistake as I knew all the faults and fixes from all the testing we’d done. While the Geoghegans did elaborate testing at Oran Park with Hardie Ferodo pads to try to go the distance, I had made at Mintex a new cooked base asbestos sintered brass chip mix pad and rear linings – M20 code so no one else had these. I elected to use them fully and change at half distance. It was a simple sum – one minute extra on pit stop – two minutes less on race time and no pussy-footing on brakes at any time. We had full brakes for the last session – the Geoghegans did not.
“Very detailed work was required on the 289 V8. This was because the manufacturing quality was very poor. Core flash in the cylinder heads had to be cleaned out or valve seats would distort and engine would overheat. It took 12 to 16 hours per head to fix this and remaking the valve seats gave me the chance to equalise the combustion chamber capacities. The inlet and exhaust ports at the valves were taken out to maximum allowable size and the head was surfaced to give maximum specified compression ratio.
“Cylinder bores had to be honed straight – .002 inch pistons and pins given proper clearance; the block was line bored for the main bearings to ensure everything was straight. It was important this was done, because the crankshaft off the production line was very bad. It had to be ground – .010 inch mains and .030 inch big ends – to achieve correct phasing and maximum allowable stroke. Then it was assembled so piston heights to the top of block could be measured. I took the lowest one, and machined the top of block to .015 clearance for that one and then took all rest to same deck height.
“Only after these operations could you balance the engine. The camshafts and lifters were good, and timing correct in engines. But the distributors were completely out. We finished up doing an exchange service on these with Ford – 12 at a time – because I was the only one who had a distributor machine.
“When I ran the car along in lower gears to heat it up, I found the first and second gear shafts had no clearance and seized. So I had to adjust the gears and make a special lube using moly and limited slip additives Anglamol and Lubrizol. Graham Hoinville, my rally navigator, was the lubricants person at BP so he was to mix up the gearbox oil especially. We did something similar with the diff. The gearbox didn’t have a breather vent, so I made one by drilling a hole straight through one of the bolts that attached the output flange casing.
“With the suspension, you had to do about 3000 miles initial running to really load up to sag the springs sufficiently. Basically you’d fit the springs in a car and drive it around on rough surfaces with four people in it. The suspension mountings and points were all corrected and the hardest rubbers in spare parts fitted. The highest of the run-in springs were put on the outside drivers’ side of car, and the diff housing was put in a press to give rear wheels a half degree of negative camber and 1/8 inch toe-in when assembled.
“I did have to argue with the ARDC about the springs. I said, ‘Well, this is what I did. I ran it in over a course which included some rough bumps to really make the springs work. You can’t say I’ve done anything to them. There’s no sign of heat treatment or anything on those springs, they look exactly the same as any other springs in the cars.’ We had done the same thing with the GT500. Also, as had been done with the GT500, every rotating part of car was balanced.
“The exhaust system joints were all checked for restrictions and then re-welded. Nothing could be done to carburettor except to ensure the correct size parts were fitted. The engine wasn’t put on a dyno; it was tuned on the road outside You Yangs circuit and inside.
“We made one red (Bob Jane and Spencer Martin) car, one white (for the Geoghegans) and one green car (Fred and me). All the rest were gold. They put 12 aside as press cars. On Sunday morning 9am on Bacchus Marsh road (Geelong to Ballarat) I ran each one to make sure it did 125 mph. I was smart enough to tell the police to come and see their new patrol cars so there was no aggro. These cars went to main race circuits in each state: Calder, Amaroo Park and Surfers Paradise. I would test run them after transporting and set a lap time. No journo broke this at any circuit – even after they swallowed their pride and had a few laps tuition.
“At Bathurst it took a few hours and slow laps to explain to Fred Gibson how to drive a touring car at Mount Panorama and my way around the circuit – he had only driven sports cars. But I thought he had the makings and all he had to do was exactly he was told, not listen to any mates – or think he knew better. After all, I had spent years finding the “way” and he had it on a silver plate in explicit detail. I said to him: ‘approach Skyline on the left of the road, look downhill and see two peaks (hills) with single tree in middle – aim for tree and go over top full chat. When you come to The Dipper, go past before turning in – you can then take lip in straighter line, and not lift the inside wheel and be going quicker in straight line through next ess bend. Doing it this way, you will be 10mph faster down to Forrest’s Elbow. When you come to third hump (last) on Conrod at 135mph, just tap brake on top of hump to keep nose of car down and air will not lift it airborne. Then it’s just three hard presses on brake to Murray’s. Give it a last press, and with the nose right down and still under brakes, give it a big flick into corner to swing tail and put foot hard on gas to finish corner on power-steer and accelerating up Pit Straight. I never forgot the look on Fred’s face when he mastered all of this and found he was equal to Fatty Geoghegan, who was the leading touring car driver, whereas Fred, a young novice, could only get better.
“All the XR GTs had a carby surge problem going across mount when in high speed left-hand drift. But this was easily fixed by raising the outside carby float 10mm. Of course, those who elected not to be told about such things and preparation in general promptly complained to Ford management about the lack of information – this included the Geoghegans – but Les Powell of Ford quoted their initial numbers back. We had the job of making sure no one had any problems.
“The start came and went, and the race went exactly to plan as far as we were concerned – clearly in the lead at half distance and having an easy run. We had our own lap scoring and all knew exactly the position. I left Fred in at last pit stop and all he had to do was as told on pit board. I let Leo nearly catch up (12 seconds) and then speeded Fred up a bit to 16-plus seconds – but to my consternation they gave Geoghegans the flag and we did 131 laps – one extra!
“The mistake was sorted out by 7pm and they had another presentation at Light Car Club of Bathurst rooms at the foot of Mountain (ED: exiting Forrest’s Elbow). It should never have happened as others knew they hadn’t won – at one point they ran out of fuel going up Pit Straight came through camping park and back of pits to back into start of pit lane. This is where they were credited with an extra lap that they did not do. They should have been excluded on the spot, but the infringement was ignored by officials under the ‘mates’ rule!
“Both myself and Ford’s managing director were not happy. Scrutineering the next day was no problem and we just put car back together and drove it home. Firth Motors bought it off Ford for about two grand and my brother used it for about three years.”