The A35 had a decent competion history - without changing the engine for a modern one. Some got phenomenal power out of the old A Series. You'll still see A35s doing well against the much bigger opposition at the Goodwood revival, etc. The basic A35 was quite a bit lighter than the Minor - as well as having front suspension of a more conventional nature, so easier to tweak.
And at least they are still the same basic car - unlike many these days in current racing that simply look a bit like the car they claim to be. Which makes for much more exciting racing to watch, IMHO.