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1973 Penske Racing Mark Donohue AMC Matador off of the $29.95 3D print option


swede70
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Greetings...

Me - contradict myself?  Oh well - for further research and the help of others like-attuned on a topic level it seems that at least on the first Holman-Moody built car which was debuted to the press, contested Riverside, Daytona and Ontario, the short arm rear suspension (bottom links then) with two links atop matters equates to the appropriate setup.  Following this, Penske Racing apparently separated ways from Hutcherson & Pagan in terms of sorting/maintaining the package, proceeding ahead to build another chassis with things configured more to the teams particular liking.  The Michael Argetsinger book Mark Donohue: Technical Excellence at Speed has been helpful to discern how long the first chassis lasted (apparently it was first scheduled to be set aside prior to Ontario, but wasn't - probably for the best given the collision with Bobby Issac), hence some research elements are coming into view.  

Reference afforded within the Paul Van Valkenburgh/Mark Donohue penned racing autobiography The Unfair Advantage from 1975 suggests that for registering awe and respect towards Junior Johnson and his efforts with the Monte Carlo, apparently the Penske team wanted to fit the long Chevrolet truck trailing arms on whatever chassis they'd campaign as the partial '72 schedule they ran wore down.  Poor aerodynamics and likely less than best power output was more to blame in retrospect, hence I'm not really sure how the second car or what was run in '73 was actually configured, although this much related, I suspect the long trailing arms made it into the package.  Later 'frogeye' Penske Matadors fielded are said to have been outfitted with the short bottom trailing arms which muddies things, although I haven't found material (yet) to confirm.

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Trying then to clean up the frame and floorboard area for filing out the residual triangular structure otherwise lingering further back along the rails as well as patching things forward to even out the profile of the oversized gussets if I have that right.  Generally looking good - if I go with this particular chassis configuration!

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Just the other side on view then.  I want the work to be clean most certainly...

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Basic beginnings on a spare cut apart chassis to the extent of plotting out a short four-bar late Holman-Moody rear suspension.  Here the springs aren't sited below the trailing arms but situated inboard, while notice too that material has been removed from the axle hump area to afford space for spring buckets, related bracework, and upper shock mounts.  Mounts for the bottom trailing arms stand to come, while the attachment points/pivots on the rear axle will likely be redone too.  Thanks for your review of this project update.

Mike K./Swede70

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Greetings...

Having taken delivery of a second 3D-printed shell, I did my best to slice the bumpers, grille, hood and trunk off of the same consistent with opening up finishing options otherwise not strictly possible.  The material used to create the rendering is alternately strong but brittle; i.e. for fine shaping after cutting away bits that snap off with a certain suddenness, things become more predictable.  Block sanding is required to come up with a smooth surface across the rendering, although once the major surface irregularities and almost topographic build up of material has been evened out, one can slowly forget how rough and hopeless things first appeared when a certain box arrived in the mail.  

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Slowly taking shape would be the vertical rows of tubes within the roll cage side protective bulges, with three rows intended to supplant the two rows as-delivered.  A coat of TS-80 Tamiya Flat Clear effectively saves my too glossy PPP tires w/markings in the wake of a misjudged selection of clear applied earlier.

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Still requiring further bumper guard reduction into the grille area in particular, but generally clean.  Soon after I cut small channels between the grille surround and bumper on each end to achieve somewhat better definition here.  The hood was block sanded, while I'll likely try to remove or at least reduce the texture of the 3D-print remaining on the underside of the same panel for more aggressive sanding.  

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While seen quickly would be the rear bumper with tail light surround/cove trim.  Also needing work, while the trunk lid needs some application consistent with rebuilding the bottom lip given I made something of a mess of it.  Even if I don't open the trunk, nevertheless it would be nice to have panel line definition otherwise scant.  Thanks for your review of this project update.

Mike K./Swede70

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  • 1 month later...

Greetings...

Having to take a step back for what now seems a bit of misdirection, seen will be the beginnings of a new chassis configuration that I hope I can carry to completion.  An AMT-boxed early iteration of the Jo-Han '72 NASCAR Torino release was purchased with the aim/idea of blending the late AMT NASCAR Thunderbird half-chassis/front clip to it, whereas out back the short trailing arm design and full frame would be retained even as the best late AMT NASCAR Thunderbird parts including the 9 inch Ford rear end might be quietly substituted in.  After awhile I couldn't ignore what I was seeing in the period research materials I was gathering, and at least for this topic, I believe this to be the best way forward.  

At some point an AMT '65 Ford Galaxie 500 XL 'Jolly Green Gasser' chassis was purchased for parts to see if that would work (not a ghastly option if one starts with a Jo-Han '70 Rebel Machine or MCW resin Penske Matador shell), whereas so too was a Revell '76 Starsky and Hutch Torino considered.  I hoping that for another attempt with yet another Starsky and Hutch chassis I might attempt a floor implant of a sorts (suggested by the photo attached), although I'll have to wait on that right in the moment.  Oh well; i.e. what seemed robust progress slows for what I overlooked before.  Thanks...

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Yet another shell appears above - but welcome if only to reduce wear and tear on the first I purchased.

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Just overlaid onto the Jo-Han frame, this is pretty much how the later AMT NASCAR Thunderbird half-chassis/front frame clip will be grafted on and in...

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It was strange to find a Jo-Han Dana 60 rear end included in their NASCAR Torino tool, hence no choice afforded to retain all Jo-Han materials out back.  Very preliminary here at present...

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...and just a sense of what extent of material might be used for the floor pans versus retaining something undetailed and too slick for my purposes.  Thanks for your review of this post.

Mike K./Swede70

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  • 4 weeks later...

Greetings...

Not much to see in total, but for picking up another Starsky & Hutch chassis I was able to fashion a pair of floor pan overlays to lend greater definition to things underneath.  In essence, the floors have been doubled up, with the integrity of the Jo-Han part topside maintained as I ponder how to alter it to accommodate the roll cage, firewall and rear bulkhead structure.  

Noticeable will be the removal of the forward third of the Jo-Han frame, with the substitution of what had simply been overlaid before.  Nothing is glued on presently, while some small additions will be made to basically clean up things before I bond things securely.  More work to come then...

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Some further floor material stands to be added forward of the transmission cross member, whereas another late AMT Thunderbird NASCAR kit will likely be sourced to afford a better firewall assembly modified to mesh well with what's made out here.  

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Just preliminary stuff, but the header collectors are Jo-Han AMC items, while unseen is the upper rear shock mount tube structure stolen from the AMT late NASCAR Thunderbird kit tack glued in-place and happily not hitting anything on the Jo-Han '72 Torino NASCAR chassis above the rear axle.  Thanks...

Mike K./Swede70

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  • 2 weeks later...

Thanks for the kind notice...

Seen is the Jo-Han '72 Torino NASCAR floor insert trimmed on the sides to allow for the reuse of the AMT late Thunderbird NASCAR roll cage protective side bulges and narrowed AMT '74 Penske Matador dashboard from before.  I'm hoping to source another floor insert given the trunk area was too aggressively trimmed and hence could fit tighter, although the rear wheel housing shapes arrived at seem serviceable enough.  

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Hoping to mark the best body shell with ink spots to delineate where I'll have to drilled a tight succession of holes to remove the hood, bumpers and grille assembly. Cutting an unseen third shell to isolate the same parts proved dicey given the material frequently shattered, although modest block sanding and drilling didn't provoke any untoward behavior in full truth.  If I can achieve reasoned results, then the effort should be that much more comparable to the old Model Car World transkit that pops up for sale every now and again.  Thanks...

Mike K./Swede70

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Kind thanks for the considerate notice, hoping to maintain pace then...

Wholly unnerved that I'd wreck my best 3D-printed shell (not 'mine', but rather what I'd purchased and worked over) for attempting the removal of the hood, deck lid, plus bumpers and grille, I'd avoided undertaking the effort until now.  Happily after seven hours of medium drama, things are generally on the up with all the aforementioned bits hacked away.  

Fine fit work consistent with ensuring the same parts sourced from another shell will live in harmony with/upon what's seen is still to come, but in the main looking good.  Another builder/friend has come through with a replacement Jo-Han '72 Torino NASCAR floor insert consistent with allowing me to try again, hence better on that front too.  Kind thanks again...

1554575070_DonohueMatador40001.JPG.7fb5cc5cce82dc0f0c4dfbe484f85b83.JPG422210675_DonohueMatador40002.JPG.6a607336a08783f0845c8fd4c45cfe12.JPG557892757_DonohueMatador40003.JPG.e58dd828430b6be61ad14947ec268c55.JPG1702936083_DonohueMatador40004.JPG.55c5faae0c0f94fa4251ac8f7b94ab08.JPG

Mike K./Swede70

Edited by swede70
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Greetings...

Tedious and fated to vanish under a coat of semi-gloss black paint, here I've revised the roll cage protective side bulges to feature three vertical rows versus the late AMT late Thunderbird NASCAR issue two rows.  All were trimmed off, the remaining horizontal tubes cleaned to disguise the work performed, then twenty-four elements were individually fitted to round things out.  Not a lot of fun in total for certain.

In addition, the panel work forward of the bulges was shortened on the spare assemblies, the dash mounts revised for shape, while a good pattern for the firewall was worked up consistent with mating such to a revised transmission tunnel to include the better part of the AMT late Thunderbird NASCAR driveline tunnel that's simply overlaid here after being cut out and isolated from a parts kit.  Some movement then...

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The small half-oval shapes help stabilize the front of the roll cage to the inside of the body, whereas it seemed best to retain the slivers of material to site the new firewall barely taking shape just forward of the dash.   The bottom third of the firewall where matters would be set on an angle and blended with the transmission/driveline tunnel hasn't yet been worked up.     

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Fairly plain at this juncture, but clean.  For clearing the profile of Jo-Han '72 Torino driveline tunnel below, the AMT Thunderbird implant will come down and blend properly.  In particular, I didn't want to lose the finely-rendered shifter platform.  Thanks...

Mike K./Swede70

Edited by swede70
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Greetings,

A friend afforded me a spare Jo-Han '72 Torino NASCAR floor insert, hence an opportunity to redo work previously undertaken consistent with working towards tighter fit of everything was had.  Notice that the floor extends out just back of the AMT late Thunderbird NASCAR roll cage side bulges to better support the paneling situated below each rear three-quarter window, while effort was also made to remove the standard Jo-Han transmission/driveline tunnel and replace such with a slightly extended AMT late Thunderbird NASCAR item.  Thanks...

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Tighter fit around the rear wheel housings as well as the trunk sides was achieved.  Here the trans/driveline tunnel hasn't yet been cut out even as a new partial firewall has been added consistent with pushing up the frame rails to where they'll need to sit.

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A lot of work briefly touched upon, the trans/driveline tunnel vanishes from the Jo-Han floor insert...

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...and just the revised AMT late Thunderbird NASCAR trans/driveline tunnel stretched forward and resting in place, while the faint seat location rails afforded by Jo-Han have here been quickly scrubbed out.  Thanks for your review of this project update.

Mike K./Swede70

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Greetings...

Here the engine assembly makes a reappearance following an effort to match the dimensions of the material added above the Jo-Han '72 Torino NASCAR floor insert.  A bit raw at this point, but reasoned as-witnessed.  Also made out would be a trimmed AMT late Thunderbird fuel cell insert cut to drop into the recess afforded within the space of the same Torino floor insert when viewed from above.  The battery is a standard Jo-Han issue.

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Mike K./Swede70

Edited by swede70
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Admittedly a very laborious walk around, here would be the result of cutting another body apart to render parts separately consistent with cleaning them further and facilitating finish options above and beyond something done all as a piece.  Not looking very good at the start, by this point the shell seems about even with the older Model Car World transkit in terms of what one might do with it.  Thanks...

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Mike K./Swede70

 

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Greetings...

Just quickly, noticed are better fitting resin bumpers as well as the hood and deck lid which rest flush for careful fitting.  

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The rear spoiler was recontoured along the back to basically reflect the 'vee' profile witnessed on the front, while the awkwardness of the fit concerning the deck lid and how the rear spoiler hung out in space appears better too...

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Focusing mostly upon the grille, I'll have to come up with some stainless steel mesh as per the recommendation of others to overlay what's made out below.  

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Separate headlamp mounts were cut from plastic sheet, the overlays formerly cut from aluminum rod countersunk into the same.  Thanks...

Mike K./Swede70

 

Edited by swede70
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  • 3 weeks later...

Thanks everyone for the kind notice...

Trying if you will to cram everything into place underneath, things are made a bit more difficult given the body is best described as being 1:26th scale while only so much room exists for the PPP tires, as well as the mash of Jo-Han and AMT parts being employed to come up with something reasonable.  Closer now for much filing of the perimeter frame in the vicinity of each rear wheel housing, while slightly bummed to note that for poor judgment the front frame clip will have to be reset given the wheelbase is demonstrably too short.  Still - pleased that the ride height is appearing as it ought, while so much of the roll cage still needs to be both fabricated and fit that the mind boggles.  Thanks for the continued interest demonstrated...

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Seen here is as good a study as any regarding the super speedway ride height.  Quite the rake in evidence...

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As confessed above, a bit short with regards to the wheelbase as unavoidably witnessed up front.  Oh well - more plastic carnage invited given one can hardly create a scale model omelette of sorts without breaking eggs...

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Moving along, the Watt's linkage is just standard AMT Penske Matador issue at present and stands to mature further, while the fuel cell housing needs to 'grow' given such isn't deep enough now that the chassis has developed to the point where I can be confident the dimensions of assemblies supporting it will remain stable.  

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Just mulling matters, the U-joints looks touch weak and will likely be supplanted with late Monogram NASCAR issue stuff, while a small divot inside the transmission tunnel begs to be filled with putty to appear somewhat tidier.  The brake calipers will be reset to match period photos regarding specifically where they'll be positioned on each corner...

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Lastly, the Jo-Han '72 NASCAR Torino lower spring perches live in harmony with the best of the AMT late NASCAR Thunderbird 9 inch Ford rear axle assembly trimmed a bit for width with the frame rails appearing quite thin at this juncture.  The shock absorber installation is still to come even as I've added the upper shock mount tubing which can't be made out here, while AMT rear springs replace the fairly tiny Jo-Han renditions I might have otherwise retained.  Kind thanks for your review of this project update.

Mike K./Swede70

Edited by swede70
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  • 1 month later...

Greetings,

Dispirited to notice that the front ride height was far too low with the all the late AMT NASCAR Thunderbird parts in place, this in addition to the too short wheelbase, matters needed to be addressed!  Seen is a revised frame featuring an extension of the wheelbase forward of the firewall, new gussets replacing what was formerly employed, and Jo-Han '72 NASCAR Torino front spindles/uprights plus lower control arms swapped in for what previously left me uninspired.  The antidive links and steering gear is necessarily separate now, although at least the major problems outlined above have been addressed.  

1229816014_DonohueMatador53001.JPG.f3120241aca5eed7d19de9052bb75231.JPG297421327_DonohueMatador53002.JPG.faace9e4ef815b7c08f071f0fa2592ff.JPG853594484_DonohueMatador53003.JPG.e153db2c92d77f8148dcfc887869cc99.JPG123658128_DonohueMatador53004.JPG.464968e6d7b93445e7d5125046444606.JPG

Boxing the lower control arms, splaying the front spring installation to a degree, and siting the front brake calipers while zeroing in on track and ride height comes next - or so it would seem.  Thanks for your review of this project update...

Mike K./Swede70

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  • 2 weeks later...

I have one of those timing lights, too. My father bought it mid 1970's. Still works.

I have some old Sears Automotive catalogs which show all the Penske stuff. Even had shifters & custom wheels.

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  • 5 weeks later...
Posted (edited)

Much thanks for the kind interest displayed by many...

Mostly sorting matters across the chassis with regards to ride height, wheelbase, track width, and pondering exhaust header configuration for good measure, seen is the model up on wheels with some preliminary headers in the form of AMT Pro Stock Gremlin parts employed.  I think I'll find another set, section in material consistent with extending the pathway each bundle of pipes downward before turning, while hoping further to chop the fairly small header collectors part and parcel of the Jo-Han '72 NASCAR Torino exhaust headers to clean up the appearance of things down below. Easily overlooked, it seems with a touch of cleaning the Jo-Han Torino header collectors can look as nice as the larger Jo-Han Chrysler Hemi header collectors - although better for size they are relative to the comparatively tiny AMT tubes leading into such.  

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Also noticeable would be the multi-part bumper, grille and grille surround assembly cast from before, but finally fit to the shell following some work to refine the opening and mounting surfaces on the 3D-printed shell well forward.  Some stainless steel screen/mesh was purchased online, the same cut and press fit with good results suggesting this will be the way to go when matters are painted and final finished.  No - I guess I didn't want to risk fouling the mesh with glue just to round out the mock up appearance of what's discerned below...

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1830526822_DonohueMatador56002.JPG.83ffac3c87c96f3fef32833fbde90cb9.JPG

...less mesh overlay, whereas still hoping to clean and scribe the remnants of the stubborn bumper guards off from the grille elements that continue to betray the existence of such.  

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As seen - sort of Desperation City with regards to header clearance around the frame and especially the upper control arms.  Better now, still tubeless with regards to chassis and roll cage members slated to be fabricated and fit.  The jacking screws were scrubbed off the top of each front spring housing for trying to reduce mass in this area, although hope exists that I can fabricate the same and flesh out what seems awfully bare at present.  Kind thanks...

Mike K./Swede70

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