Waste of time though. By the time you've done all this, Joe Smith has fitted a Griffon to the Spit Mk.IV DP845 and flown it in 1941, which set up a chain of events getting a Griffon into a far more worthy airframe.
In July 1942, DP845 was placed in a competition of sorts between a recently captured Fw 190 and a Typhoon as a comparison, at Farnborough and Jeffrey Quill was asked to fly the Spitfire. The thing is, no one present except Smith and Quill knew the Spit had a Griffon under the hood. Quill's own recollection of the event from his autobiography, Spitfire A test Pilot's Story:
"On reflection the general scheme became clear. The Spitfire was to be a sort of datum pacemaker - 'Mr Average Contemporary Fighter' - and its job would be to come in last, the real excitement of the proceedings being by how much it would be beaten by the FW 190 and the Typhoon, and which of these two bright stars would beat the other and by how much.
Outside on the tarmac at Worthy Down stood the inoffensive-looking but highly potent DP485... All went according to plan until, when we were about halfway between Odiham and Farnborough and going flat out, I was beginning to overhaul the FW 190 and the Typhoon. Suddenly I saw sparks and black smoke coming from the FW 190's exhaust... and I shot past him and never saw him again. I was also easily leaving the Typhoon behind and the eventual finishing order was, first the Spitfire, second the Typhoon, third the FW 190. This was precisely the opposite result to that expected, or indeed intended. It certainly put the cat among the pigeons and among the VIPs."