Classic american car restoration

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03 April 2018

Restoration Stories – Bringing to life a 1968 Roadrunner

The client bought this 1968 Plymouth Roadrunner on eBay, it arrived complete & appears here partially dismantled. The brief was a full rebuild to a high spec, salvage engine parts where possible & stiffen the body shell to improve handling.

The rear quarter panels and around the wheel arches are seriously rusted with significant loss of original panel material. The plan is to cut in new lower sections to the quarter panels thereby preserving the clean top edge of the rear quarter and the detail line below it. This method is better than replacing the entire quarter section because it preserves the original top section.

The extent of the damage to the entire Roadrunner underbody is clear in this shot. Here we have cut out the trunk floor, both the rear footwell panels and both front footwell panels including the transmission tunnel. Importantly, the nicely designed rear light surrounds are undamaged – these details are very difficult to repair once damaged. The roof of this car was also in good condition.

Most of the Roadrunner trunk floor panel has been removed, the rear chassis rails were also badly rusted and will be replaced, some areas at the base of the rear wheel arches are corroded and these will be repaired as necessary. For a good restoration it’s important to always preserve details like the spare wheel fastener which will be cut away and re-welded to the new floor.

The entire Roadrunner interior footwells have been removed including the transmission tunnel which had been butchered along with the transmission tunnel cross beam which had been completely cut away. The floor panel braces are intact which is good. The firewall is in reasonable condition as are the door shuts and the roof gutters.

1968 Plymouth Roadrunner 383 cubic inch engine – we only managed to salvage the block! Two of the cylinder linings were damaged so we had them re-sleeved.

The Roadrunner front subframe was in good undamaged condition.

The Roadrunner front sub-frame after shot-blasting, re-sprayed in black.

The underside of the trunk floor panels. 1968 Roadrunner trunk panels are supplied in two parts and require careful fitting. These were cleaned up to remove surface rust before being coated with red oxide rust inhibitor before preparing for the undercoat and paint finishes.

Here’s a clear view of the repairs to the rear of this ‘68 Roadrunner. The body shell has been shot-blasted clean in our full size blasting booth. The two chassis rails have been replaced as well as the xxxxxxx brackets. The bases of the rear wheel arches have been repaired in preparation for the fitting of the floorpans. A new rear beam has been fitted and before the lower trunk panel was removed a stabilising bar was tack welded across the trunk opening to ensure it was secured rigidly ensuring the new lower panel would be a perfect fit. At the top of the photo you can see the lower rear windscreen panel has been fitted but not yet welded up so it’s held in place by a pair of mole grips. The trunk lid gutter channels have some rust holes which will be individually repaired.

The floor-pans have been tack welded into place. There’s still a lot of repair work to be carried out around the edges of the wheel arches.

The new Roadrunner floor-pans are welded in, the inner rear wheel arches have been repaired and the fit is good. The trunk lid gutter channels have been repaired and the rear windscreen lower panel is welded in place. This is skilled work, it is not always straightforward because the quality of some reproduction classic American body panels can be unpredictable, a lot of tweaking is required before the fit is perfect, this is time consuming work because even tiny variances in alignment can cause considerable problems during the later stages of the rebuild.

The floor-pans and inner wheel arches are finished and the lower rear trunk panel is welded in place. The left rear lamp panel had to be replaced after all. There are some small rust holes in the original trunk lower lip and some others on the underside of the lid, all these will be individually repaired. One of the great advantages of shot-blasting the entire body shell is there can be no hidden rust.

It was decided to replace the entire left rear quarter panel and here it is clamped into place, these are huge panels so a lot of care must be taken to ensure 100% correct alignment. The leadwork over the manufacturer’s original weld (pillar/roof panel) is clearly visible on the left rear roof pillar, there are some small rust holes below the leadwork which will be repaired.

A good second hand Roadrunner transmission tunnel cross beam has been welded in. New floor-pans visible above. Also visible, running longitudinally towards the rear of the car is one of a pair of stiffening bars welded in to provide additional torsional rigidity to this E-Body (correct Mike, or is it a B-Body?) car.

On the other side, the right hand stiffening bar, the brackets which support the cill and the floor-pans will also be welded to the stiffening bar. The cill still needs to be repaired and tidied up.

The huge one piece front floor-pan incorporates the transmission tunnel and fits well. Once this is welded in most of the structural work will be done.

The restored 1968 Roadrunner body shell is still mounted on a moveable frame, all repairs completed, fully shot-blasted and ready for final preparations before being put into primer.

Body shell in primer. As can be seen from the previous posts, an enormous amount of preparation and careful work goes into reaching this stage. After re-spraying the body shell, installing the engine, gearbox and drive train is relatively simple, suspension components are straightforward too but the wiring loom, interiors, dashboard, and trims are awkward and time consuming!

Chrysler V8 383 cubic inch big block. The only engine part salvaged from the original was the block, we cleaned it and sprayed it in black Hammerite paint which gives a good smooth finish. Two cylinders had slight damage and they were re-sleeved. Full engine rebuild kit ordered and fitted. Standard heads were discarded for Edelbrock aluminium heads

Written By

Mike Sargeant

Mike Sargeant, owner of Tornado Automotive, is a professional car restorer and mechanic specialising in classic Amercian vehicles based in High Wycombe, United Kingdom. See company page for more.

Call 01494 531285 to discuss restoring your American classic car

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