Hello Ghosthunter,
Thanks for the detailed illustration. I now see the difference for the long and short engine you described.
I checked all the models I have for the inner arch areas and engines. Below is a summary table which i hope is easy to understand. I use similar Excel table to keep track of what variants i'm short of (the 6 empty cells).
- hwsscast.jpg (64.58 KiB) Viewed 2204 times
In the table, "Blocked" means blocked inner arch areas and "Clear" means clear inner arch areas; "Long" means long engine and "Short" means short engine.
So a "Blocked / Long" would means the particular model has got blocked inner arch areas and long engine.
The result is somewhat conflicted with your information. From your notes, clear inner arch areas is classified as early casting and long engine is also classified as early casting. But from my models, clear inner arch areas is always associated with short engine, while blocked inner arch areas is always associated with long engine. The only exception is the orange body brown interior variant (highlighted in yellow). It's got clear inner arch areas but long engine, which could be a transitional issue.
It's interesting to find out that a particular colour may got 2 castings. For example your red (brown int) model is long engine (assume blocked?) but mine is "clear / short".
I'd like to propose a bold hypothesis that, the prototype (shortest engine) came in first. And because too short the engine resulted part of the baseplate exposed from the gap, for the release they made the engine longer (the "Clear / Short" variants). Then they extended the engine length further (the "Clear / Long" orange model). And finally the inner arch areas got blocks (the "Blocked / Long" variants).
But this is immediate challenged as you mentioned that the first colour issue (red) has long engine, while the later blue issue has short engine. In addition, the initial release should be the Grey models which I got "Blocked / Long" examples. I doubt there exists Grey models which is "Clear / Short". Ghosty, from your first image showing the front wheel-arch with the grey and blue model side by side. Your grey model has clear inner arch areas, is it a short engine non-blacktop model?
And finally, a line-up of the 10 basic models.
- DSC_1534s.jpg (42.75 KiB) Viewed 2204 times
Cheers,
R