NON "MATCHING NUMBERS" ACE

[Laurence Kent]

I have owned AEX 443 for 26 years. For many years I believed an aspect of its provenance that proved to be incorrect, but a year ago I was able to sort out the car's correct history, which coincided nicely with the end of the restoration, which on an-on-off basis took a full 25 years!
      I have no intention of ever selling the car, but I am curious about its value.  While I know what Aces are going for, mine doesn't have its original AC engine. In 1967 it was converted into an Ace-Bristol. The owner of BEX 437 had raced the car at Westwood very successfully, British Columbia, the only official FIA racetrack in the Americas in the late '50s and early '60s.  As the '60s progressed, BEX 437's competitiveness diminished and its owner sold it to someone who chose to butcher it and turn it into some sort of "Cobra", but with a Chevrolet motor. Thus in June of 1967 my car inherited from BEX 437 its Bristol badges, speedometer, tachometer, gearbox, oil cooler, wider exhaust manifolds, beefed up racing clutch, and #804 100 D-2 motor, that had in 1960 been upgraded to factory "S" specifications, and in 1961 then been upgraded further with a Roy Shadbolt camshaft and higher compression.  While a very fast car and very pretty, because it looks very standard, my question to anyone out there with some knowledge about values is this: what would its value be compared to a "numbers-matching" Ace-Bristol?  While I assume that the non-original engine and gearbox bring down the value (or isn't it that much of a factor given the rarity of these cars?)...one also needs to take into account that it's a very fast 180 hp car with a motor, gearbox, etc from an Ace-Bristol that had a serious racing provenance. Balancing everything, any rough estimations of what the value of this car would be versus a "numbers-matching" Ace-Bristol D-2 with no racing history? I am thus not asking for monetary estimates, but rather something along the lines of "about ten-per-cent less", or "about the same", or whatever.
           Thank you very much for any input you may be able to give.
   
                             Laurence in British Columbia