Hi Craig,
These are some notes I made while researching Arntz cobras, whether they're right or wrong I don't know. Most if not all the info probably came from posts on this site.
Version 1
Body oblongish fenders and wheel wells.
No steel support or bars in doors
Primative latch and hinges
Simple wheel well liners and interior panels
Version 2
Addressed body shape issues
Front guards aren't identical
Wrap around steel crash bar behind interior pockets.
Stronger cowl brace to stop shake.
Large rectangular door beam that uses a VW latch.
Rear suspension dimensions are different.
Version 3
Used Butler bodies
Frame modified to take a Doug Nash 5 speed.
K member rather than x members
There were some with a mixture of versions
Fan shroud on type 2, 3 and Butlers, but not all cars had them. Usually combined with heat shields on foot boxes.
No difference between Butler and Version 3 Arntz.
Last 16 type 4 cars had the kick in the hood.
104 Butlers were made
Butlers had a 91 inch wheel base
Butler stamped the chassis number on the main rail drivers side between the front suspension and radiator. BRIMMYYZZ
BRI - Butler Racing Inc
MM - Month
ZZZ - Build number
Maybe there is something there that you haven't seen yet. I doubt it though.
