Beautiful work...I can imagine a lot people will now be doing searches for Pink corvettes on eBay, I know I will be.
As a long-time Tamiya RC enthusiast I don't think the chassis used on the original prop in this photo is from the Subaru Brat:I'm not sure how I figure out the wheels and tires but I did. Chris Walas only used the body of the 1979 Barbie Dreamvette. For the remote control undercarriage, they used a modified 1/10 Tamiya Subaru Brat. These go for a pretty penny these days so I wasn't going to pay for one of this I need it another solution. I found they still selling new Tamiya Brat tires and wheels not to bad in price so I got a set of these. I also for coincidence found the exact Barbie Dreamvette on eBay and I bought it.
As a long-time Tamiya RC enthusiast I don't think the chassis used on the original prop in this photo is from the Subaru Brat:
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The Tamiya ORV chassis used on the Tamiya Frog, Brat, Lancia Rally etc. family of models uses independent trailing arm suspension. so the rear wheels usually have no camber (until the wheel bearings wear, when they end up with negative camber).
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The rear wheels in the original prop picture above have positive camber, which is a hallmark of the independent swinging arm rear suspension of the Tamiya SRB (Special Racing Buggy) chassis which used a scale replica of the VW Beetle's front and rear suspension.
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The chassis in the prop photo also has a lot of ground clearance, which the ORV chassis did not really have (particularly at the front).
There were three models produced with the SRB chassis, introduced in 1981 - the Sand Scorcher (a Baja racing VW Beetle), the Rough Rider (a Baja racing Funco Buggy, based on the real Bel Ray Bullet) and the Ford F-150 Ranger XLT (a Baja racing pickup truck). You can see from this picture of the Ford Ranger it has the distinctive positive camber on the rear wheels:
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The SRB chassis was basically a flat fibreglass plate with the front and rear suspension modules and radio box screwed onto them, so it would have been very easy to make a custom-length chassis to fit the Barbie Corvette body (you can see a custom-made flat aluminum plate chassis peeking out from below the side of the Corvette body in the picture). The F-150 model in particular introduced the 8-spoke wheels and Sand Blaster 915 front and rear tyres seen on the prop. The front wheels on the Ranger originally had a very deep offset to compensate for the narrow-track SRB front suspension (which can be seen in the prop picture and catalogue photo above). When the Subaru Brat was introduced in 1983 the 8-spoke front wheel moulds were modified to reduce the offset by 5mm as the original Ranger wheels stuck out too far from the body on the Brat due to the wider track front suspension of the ORV chassis (the wheelarches on the Ranger body mould then had to be modified so the new narrow-offset wheels did not rub at full steering lock). The picture below shows the back side of both types, with the newer Brat wheel on the left and the original Ranger wheel on the right:
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Tamiya did re-release the Sand Scorcher, Rough Rider (as the Buggy Champ) and Subaru Brat a few years ago (which is why the wheels and tyres are still available as spares), so with the chassis from a Buggy Champ SRB kit (which are not cheap by any means, due to the amount of metal castings involved) and the Brat wheels you could make a 95% accurate reproduction of the prop. For the full 100% accurate you would need to find a pair of vintage early Ford Ranger front wheels with the deep offset though.
Your Gizmo looks awesome, even after just the eye and "fur to forearm" upgrades. The ToT version looks so "dead", it makes them not doing it right make it all the more depressing. I really wish I had the talent to build one of these for myself, excellent work!
The prop overall looks good, if in a sad state. Don't forget, that there was probably a charge and a squib on it that went boom after he ramped off that shovel(and crashed), so it probably isn't from abuse or lack of care, so much as what was leftover after doing the SFX shot. Physics and explosives have such a negative effect on plastics and such .