C3 rear end paint of parts and engine #

[Melvyn Hiller]

[Joe L.]

Re: C3 rear end paint of parts and engine #

Melvyn------

By "rear end" I don't know if you're referring to the differential unit or the entire rear suspension. In any event, the differential unit (i.e. "pumpkin")is natural cast iron or steel with respect to all externally visible components. This includes the case, the cover, the stub axles, and the pinion flange.

I believe that your car could have had either a GM casting #3955270 or 3963512 block. Most likely, it would have been the 3963512, though. However, if you were to find a 3955270 block that was correctly dated for the car, it could have been originally installed in the car. The ONLY way to know, for sure, which block casting was originally installed in the car would be to have the block originally installed in the car.

Cylinder heads should be GM casting #3931063.

By the way, your car was built in September, 1969 and not August. In fact, my original owner 1969 is serial number 29531 and was built mid-September, 1969, so it was built just a few days after yours.

[Kent K.]

Re: C3 rear end paint of parts and engine #

Melvyn,
Joe didn't cover your question but N14 side exhaust was available during the 1969 model year. In fact, my August built '69 (one previous owner) has the factory installed side exhaust system. Good luck with your '69.
Kent #6201

[Melvyn Hiller]

[Joe L.]

Re: C3 rear end paint of parts and engine #

Melvyn----

The "pumpkin" is a term for the cast iron case which contains all of the pieces of the differential.

As far as judging goes, anything other than a natural finish on parts that were originally natural is going to result in a loss of points. For practical purposes on a driven car where judging is of secondary or no importance, cast blast works very well for originally cast iron components. For originally natural components on a judged car, cleaning them as best you can and using a coating like Pre-Lube 6 (available from Quanta Products) might be the best. However, it has to be regularly re-applied.

What I mean by "having the block originally installed in the car" is that, in cases in which more than one block casting might have been used for any particular car, the only way you could know which one was originally installed in the car would be to have that block in your possession. Once it "leaves" the car or your possession, there's no way to know which one was originally present in your car. However, for your car, either of the 2 blocks that I mentioned, if dated within 6 months prior to your car's build date, would be considered "correct" for your car regardless of which one was ACTUALLY originally installed in the car.

Other rear suspension component finishes:

strut rods----natural, as-forged finish

sway bar-----natural, as-forged finish

sway bar links---natural steel finish

sway bar brackets (attached to trailing arm)----semi-gloss black

rear bearing supports-----natural cast iron

rear caliper brackets-----natural cast iron

calipers-----semi-flat black, except natural on all machined surfaces

rear brake backing plates----galvanized or, possibly, zinc plated

trailing arms-----semi-gloss black

spindle flange-----natural cast iron

half-shaft flange-----natural, as-forged finish

half shafts-----natural, shot peened finish (big block)

shocks-----painted, gray to blue-gray

shock mounts----zinc plated

removable crossmember (differential mount)-----semi-gloss black

spring-----mostly gray Ionoklad coating on exposed surfaces. Some areas on spring leaf edges may be natural. Ionoklad coating available from Quanta Products;

brake discs-----natural cast iron

[Melvyn Hiller]

Re: C3 rear end paint of parts and engine #

Thank you thats make all clear I appreciate all you knowledge thank you very much Melvyn

[Mark #28455]

512 block is correct

If I remember correctly, the 512 block was being cast as of about October 1968, so if the NCRS "rule" of 6 mos were applied to the block casting date, only the 512 block would pass as the car was built nearly a year after that.

Mark