Haven’t posted a project in a bit so here an interesting one t hat will also answer many questions other many have regarding auto to manual swaps, transmission selection, exhaust modifications, carb and distributor tuning.
Had the opportunity to transform a car’s personality from nice leisure cruiser to gear banging spirited driver. This T/A has some prior internet fame going by the name ‘Marty’ primarily the abbreviated of the Martinique Blue color name. Intent was to ‘wake up’ the car and swap the transmission from the stock TH350 to a Richmond/ Doug Nash 5 speed all while retaining a stock appearance. The changes could also be considered ‘Day 2’ mods such as Mecham Pontiac of DKM/ Macho T/A fame would perform on new T/A’s back in the day.
Subject:
1978 T/A
WS6, 400 L78, auto, 2.56 rear, 31k miles. Very clean and well preserved car.
For the Factory markings people
Factory service dept ‘test pipe’. This was installed to test if the catalytic converter was faulty. Some were installed to test and were ‘forgotten’ to be removed.
Even with careful scraping, colors of stripes are undistinguishable.
36 year old underside. Oil pan should be painted. This pan was removed in its prior history for reasons unknown.
With the Th350 & exhaust removed, one can see additional factory markings
Some stuff that fell out of the car. All but the driveshaft will be shelved safely for originality purposes and not discarded. D-shaft will be reused.
New ceramic coated 2.5” RARE manifolds
All parts required for a complete auto to manual swap for St-10 4 speed or DN 5 speed. TKO’s and T56s will have some different parts but interior parts will be the same. Pictured is the Richmond 5speed or commonly referenced as Doug Nash 4+1.
Since we were there and it was leaking, the oil pan gasket was replaced w/ a 1 piece gasket. Pan and engine was touched up w/ GM corporate blue but saving original color markings. Inside a 31k mile engine
Conversion begins to take place
Manifolds and clutch linkage
New look
Better breathing. 2.5” all the way.
Tips in factory position as car was received.
Console before
After
Peak a boo
Installed w/ all factory or factory repop 4 speed parts
Carb rejected for richer mixture both primaries and secondaries and distributor recurved so all 36 deg of timing advance comes in by 2800 rpm.
Overall the job was a success. Car has changed personalities for the better and is much livelier and has decent pick up. Even with the 2.56 rear end gears thanks to the transmission’s deep 3.27 first gear. Fifth is still 1:1 so the high gear in the back is needed. Most run 2.73 or 3.08 for road courses but this application was perfectly fine with the OE set.