Yes thankyou, that would be the trick, now the question is could the UK have produced such a vehicle in numbers ready for Normandy?
No, they could not. That's a flat out fact.
The UK could barely provide enough Fireflies for 1 vehicle in 4 in combat units and that really wasn't enough and it only involved relatively minor changes to the Sherman turret and innards. Doing what the Israelis did to make the M50 to the Churchill turret would have been significantly more work than the Firefly conversion and then to add the massive rebuild of the arse end to add the Meteor (if it was even possible)? No, there simply wasn't enough time.
One also have to examine the Churchill as a basis for such a conversion. If you could get the top speed up to 25 or so MPH, then, yeah, it might be worth it, but the rebuild time/cost would have been immense for each vehicle. And, frankly, the suspension probably wasn't up to moving that vehicle much faster over broken ground. The small wheel system really isn't good for speed over undulating terrain.
Then you have to imagine how it would be used. If it was to provide an armoured suport for infantry against German tanks, it could have been useful and would not have needed the engine upgrade. In that role, it might be worthwhile. However, of course, the tank destroyers were used in that role with success when required, so I'm not sure the need was really there. What was needed was a cruiser with a 17 pdr and the Comet and Firefly adequately filled that niche.
Remember, the needs of the attacker are always different than those of the defender and an upgunned Churchill would have been best as an infantry defender, but would not have been good as an attacker. And, in the final analysis, attacking is what the Allies were doing for the entire last year of the war, individual defensive actions notwithstanding.
Paul