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Jim Cushman Duster

 
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Bluesman Mark



Joined: 01 Mar 2018
Posts: 25

PostPosted: Thu Mar 01, 2018 5:29 pm    Post subject: Jim Cushman Duster Reply with quote

Now that the forum is back up & running, here's some in progress pics of a current project, making the AMT Cushman Duster Kit Car more accurate.

Some of you in Facebook racing or model car groups may have seen these already, but I can have them properly organized & captioned in this thread.

As the kit itself features a great 12 page reference book full of color & B&W photos of the 1/1 car, you can use those to fix many of the kit's issues. Also, some of my photos feature comparison shots with a Millennium Edition Dart Kit Car model, which is identical other than the front fascia & bumper.

First up, let's look at the cowl box & air cleaner on the 1/1:





The kit has the cowl box molded to the hood, but a line is scribed into it. Just follow that line & cut the box free from the hood.





Then open up the cowl vent, as in the photo. You're going to cut it open further once you glue the box in place, to match the 1/1, but having the box glued in place will give you the added strength needed to keep from cracking the cowl when you do that. glue it in place on the cowl. The unmodified Dart body is on the left in this photo & all others, for comparison:





You can also see where I've cut open one side of the cowl box as on the 1/1. We'll cover that & opening up the cowl box itself in a later post.
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Bluesman Mark



Joined: 01 Mar 2018
Posts: 25

PostPosted: Thu Mar 01, 2018 5:38 pm    Post subject: Reply with quote

You saw where the air cleaner on the 1/1 is quite large, much larger than the one in the kit. Here's comparisons shots of the air cleaner before 7 after the fix. I used strip styrene, (Evergreen), wrapped around the front & sides, & a pice cut to fit the top.

In the first pic, the Dart air cleaner is on the right, the modified one on the left. All others are the opposite:







Much better looking. When test fitting it to the intake, I had to carefully sand down the strip to get it to snuggle up right.

When the kit was tooled up, extra material was added to the front fenders than was on the 1/1, as if they had replicated that accurately, the front fenders would have drooped severely when the still warm body was pulled from the mold. The pic of the 1/1 shows how it needed to be:



Using where the extra material was molded into the body as my guide, I began scribing the fenders out, on the inside, until I got them correct. Here's a comparison pic:

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Bluesman Mark



Joined: 01 Mar 2018
Posts: 25

PostPosted: Thu Mar 01, 2018 6:21 pm    Post subject: Reply with quote

For years, it's been said that the engine in the kit is severely undersized. Compared to the small block Mopar engines in the 90s tool AMT Duster & the 70s annual 75 Dart kit, this turns out to be true. My original intent was the use one of the 90s tool Duster engines, but also more narrow looking as well as longer, with a sharper V to the engine configuration, which almost makes the engine resemble the Dodge V10! The Dart annual kit provided a better engine. Mine came from the RC2 era reissue, mislabeled as a Duster!



Here's the difference between the Cushman engine & the Dart engine:



While the Cushman Duster has the heads molded in place, it's smaller overall than the Dart engine.

A word of note, the Polar Lights Chargers, (STP & K&K), have a small block Mopar engine in them. In fact, it's the only engine in the STP kit. There's a serious problem with it however, in that at what's supposed to be 1/25th scale, it's actually larger than the same engine in the oft reissued 1/24th scale 1970 Dodge Challenger! I don't recommend this engine for the swap, for obvious reasons.

Using the engine I picked out created another problem; in that the dry sump for the Cushman Duster is too short for the Dart block. An easy solution is the larger oil pan included in the Dart for the optional Pro Stock Hemi. Measure & mark where to cut the front of the Hemi sump:



Then glue it onto the front of the Cushman sump:



A little putty to smooth out the transition is all you'll need to add. The bottom piece of the dry sump has sink marks on both the top & bottom, I filled those with CA glue & accelerator & sanded them flush.

Using the cylinder heads from the Dart, I glued a piece of styrene to the bottom of each one to raise them just enough to better replicate the bulk & height of the Mopar W2 racing heads:



A serious accuracy flaw in the kit is it's five hole rims, shared with the other variations done by AMT:



The 1/1 used nine hole rims:



Look for one of the 90s era AMT Olds Cutlass NASCAR kits for the correct rims. I specify this kit, (or any of the AMT GM variations), because it's going to give up some more parts to make this build more accurate, (some of which might surprise you!). Those old AMT kits tend to be dirt cheap & have a lot of parts for a lot of different models. I picked one up open but complete at a model car contest/swap meet in Omaha last year, for three bucks:

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Bluesman Mark



Joined: 01 Mar 2018
Posts: 25

PostPosted: Thu Mar 01, 2018 6:34 pm    Post subject: Reply with quote

The 1/1 had a dry break fuel filler & an overflow tube, neither of which is in the kit:



A friend of mine supplied me with three aftermarket dry break fillers, (as I also plan to do the Petty & Millikan Darts), so I have no idea who offered them. Looking online might help if you're interested in them. He included two overflow tubes in the package, & a third one can be made from the smallest K&S aluminium tubing for the third kit I build.

In order to find the correct location for making the filler hole, I accessed the following pic on my smart phone, enlarged it to match the size of the kit body I was holding, then carefully, (so not as to damage the phone), took the measurements off the photo with my digital calipers:



From there it was easy to drill a starter hole, then enlarge it to filt the filler in:







Since taking those photos, I've since got the filler to fit flush, like the 1/1.

The overflow tub on the 1/1 was located right where the trunk lock is. so I just drilled out the lock & glued in the tube:



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Bluesman Mark



Joined: 01 Mar 2018
Posts: 25

PostPosted: Thu Mar 01, 2018 7:08 pm    Post subject: Reply with quote

The kit's floorpan has the seat mount molded into it, which is understandable, but it leaves a visible open space when viewed from underneath:



Some appropriately sized Evergreen half round styene glued in place & puttied over fixes that issue:





The front cover has a horrible sink mark where the lower mounting post on the back of it is located. I trimmed off the post, drilled out the sink hole & glued a piece of styrene rod in to fix that issue & act as a mounting post:



There are two ejector pin marks on the engine mount, one of which is in the crease. CA glue & accelerator filled those:



I mentioned the AMT Cutlass, well, the valve covers in it are much better looking than the Mopar ones. Sacrilege I know! Well not really. When Mopar was developing the 340 LA small block in 1966, to be introduced in the 1967 model year. 1966 is when Chevy came out with the 327 CI/350 HP Corvette engine in the Nova SS. Chrysler's engineers got one for comparison when the LA engine development was already well along, & were amazed by it. They then went back & copied the port design of the Chevy heads as closely as possible for the 340. Turns out that due to the head bolt arrangement on the Mopar block, they had to change it a bit, & wound up with an even better breathing engine than the Corvette small block. because of that, many of the parts in the SBC engine look more correct for a W2 Mopar engine., including the valve covers, especially in their height.

The problem with the SBC valve covers is heat shields are molded to the lower edge of them, & removing those weakens the covers, & makes them too small. Also, they are longer than the heads on the engine I'm using.

I simply measured the covers compared to the Mopar heads, cut them to fit & glued them back together, & then glued each valve cover to a sheet of styrene, then trimmed the styrene to fit around the valve cover, (top & bottom, not the ends), once the glue dried. I also glued styrene to the bottom of the covers to add mounting posts to the covers.

Here's a couple of pics of one cut & glued to the styrene next to one waiting to be trimmed to fit:



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Gary Davis



Joined: 02 Feb 2018
Posts: 150
Location: Tacoma,Washington

PostPosted: Sun Mar 04, 2018 5:57 pm    Post subject: Reply with quote

Hey Mark.....I really want to see your work and the corrections on this kit but...the pics are just too big. I have to hunt for the part in the picture to try and view it. Way to difficult to view bud...
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