Welcome back, Brett.
According to Paul's (Classicus) Frua registry, there are now 70 AC 428's accounted for, in total. Included in that total are 428's re-bodied as Cobras.
That's a very thin market.
A thin market makes valuation difficult.
"Story" cars don't appeal to some Collectors. Many "collectors" want something immediately identifiable, and desire 'the best of the best' to lord over other owners of the same make or model.
Here's an example: the 1958 Chevrolet Impala - a car that has many admirers, and pulls good prices today:
With a six-cylinder engine, a Chevrolet Bel Air Impala started at $2,586, while $2,693 bought a V8. In all, 55,989 convertibles and 125,480 Sport Coupes were built, 15 percent of production. Interiors held a two-spoke steering wheel and color-keyed door panels with brushed aluminum trim. (copied from Wikipedia)
OK! more than 175,000 Impalas built in 1958. Just 15% of the otherwise Identical total production of chevrolet for that year. Some Impalas sell for MORE than CF31 fetched at auction! Confounding? OK - everything sells for what "the market" determines. But REALLY!....
I think it's odd (here in the USA) that Corvettes (for example) have such a strong market pull. There are 100's of thousands, possibly more than a million Corvettes still in existance. What is "rarity'?
Most American cars sold 100's of thousands of examples, year after year. Mass produced. I've seen cars being auctioned, and touted as "1 of 1" because the car was ORIGINALLY painted teal, with a three speed column shift and "dog dish" hubcaps! Well whoop-de-doo! That's "exclusivity" for you. (Who could possibly care?)
The unusual aspect of 428's is their undeniable lineage starting from the ACE through the Cobra. A little esoteric for some, a little too complicated, perhaps - but clearly true.
I think this makes the car VERY desireable.
Some quibble that the 428 has no visual kinship to the "Cobra" shape. My retort: who cares?
Which is more important:
1) What it LOOKS like.
-or-
2) What it does, and how well it does it.
It's a GT!. It was not intended to be a race car - though it COULD be raced (Andy + Boris).
It can easily trounce the competative cars of it's era.
It's genuinely extremely rare.
It's very good looking (to most eyes)
It can be serviced, maintained and improved economically. (consider Ferrari, Maserati, Aston Martin etc. How much for an engine re-build? Suspension upgrade?. There's no comparison!)
Truthfully, Brett - low mileage really does not matter much regarding 428's. They can easily be fixed (compared to other "Exotics" of the period). All the running gear is available, much of it improved over time.
Frankly, I doubt many 428's actually accumulated much mileage. My car, for example, ran so hot that 30 minutes was about as much as the driver or the car could stand.
So now - it's fixed! (and by "fixed", I mean WITHOUT making any 'chemical' change). Runs cool - passengers happy, engine happy.
And I've got an indicated 44,444 miles on the odometer. More to come, I expect.
'BLOW WINDS! CRACK YOUR CHEEKS!". There's no accounting for taste. And it's tough, arguing with "what is" vs "what should be" (according to me, I suppose)
---end of rant---
sorry
