67 Differential Bolts / Diffy finish

[Brandon K.]

Anyone familiar with the correct finish and head markings for the rear end cover bolts on midyears? I'm wondering if mine are original or if they've been replaced.

Also, for judging purposes, would I be better off painting the casing black, cast blast, or stainless steel? I know it should be "natural" but its too pitted for just using a clear coat. TIA.

Brandon Korman

[Jack H.]

Re: 67 Differential Bolts / Diffy finish

Hum, casted surfaces WERE rough. Don't see why it can't clean up nicely in a blast cabinet....

You can coat with anything you desire, hey, it's your car! But, on the judging field any coating that is detectable (naked eye to the judge) is an originality deduction potential. If the surface was natural leaving the factory and it's painted/coated on the judging field AND the chassis judges detect the non-factory foreign coating, the item qualifies for a loss originality points based on FINISH.

Now, if you're driving your car and leave the cast surface natural, you WILL gather minor surface rust. NCRS guidelines are to disregard MINOR rust on natural parts (MAJOR rust is another issue) because that happened to parts just sitting in the warehouse and/or in transit to the final assy line. Plus, for cars driven to an NCRS meet, the owner gathers 'bonus' points to compensate for such wear and tear.

So, it's your call here. If you're building a trailer queen for a max concours effort, leave the pumpkin natural and spritz some WD-40 on 'er from time to time to reduce excessive rust. If you're building a driver you want to show, go anyway you desire and relax knowing your milage driven credits will offset the intentional deviations and wear/tear. We say we encourage members to drive their Corvettes and the club backs this policy with its scoring rules.

[Jack H.]

Re: 67 Differential Bolts / Diffy finish

Hum, casted surfaces WERE rough. Don't see why it can't clean up nicely in a blast cabinet....

You can coat with anything you desire, hey, it's your car! But, on the judging field any coating that is detectable (naked eye to the judge) is an originality deduction potential. If the surface was natural leaving the factory and it's painted/coated on the judging field AND the chassis judges detect the non-factory foreign coating, the item qualifies for a loss originality points based on FINISH.

Now, if you're driving your car and leave the cast surface natural, you WILL gather minor surface rust. NCRS guidelines are to disregard MINOR rust on natural parts (MAJOR rust is another issue) because that happened to parts just sitting in the warehouse and/or in transit to the final assy line. Plus, for cars driven to an NCRS meet, the owner gathers 'bonus' points to compensate for such wear and tear.

So, it's your call here. If you're building a trailer queen for a max concours effort, leave the pumpkin natural and spritz some WD-40 on 'er from time to time to reduce excessive rust. If you're building a driver you want to show, go anyway you desire and relax knowing your milage driven credits will offset the intentional deviations and wear/tear. We say we encourage members to drive their Corvettes and the club backs this policy with its scoring rules.

[Gene M.]

Re: 67 Differential Bolts / Diffy finish

Even the fresh bead blasted surface won't look correct, even worse with oil all over it. It should have that gray ductle iron look. The blasted part looks kind'a silvery. I would use the cast spray and take a point loss it will stay looking good with out the need of spraying it with oil every month. Oh, and the bolts and lock washers are gray/black oxide on the cover, cam bracket, and securing the spring.

[Gene M.]

Re: 67 Differential Bolts / Diffy finish

Even the fresh bead blasted surface won't look correct, even worse with oil all over it. It should have that gray ductle iron look. The blasted part looks kind'a silvery. I would use the cast spray and take a point loss it will stay looking good with out the need of spraying it with oil every month. Oh, and the bolts and lock washers are gray/black oxide on the cover, cam bracket, and securing the spring.

[Bill Clupper]

Re: 67 Differential Bolts / Diffy finish

In addition to Gene's advice, you might try a light dusting of black over the cast blast paint to achieve some variation in the surface color to more nearly match the original "as cast" finish.

[Bill Clupper]

Re: 67 Differential Bolts / Diffy finish

In addition to Gene's advice, you might try a light dusting of black over the cast blast paint to achieve some variation in the surface color to more nearly match the original "as cast" finish.

[Keith B.]

Re: 67 Differential Bolts / Diffy finish

I have had good success using two spray cans at once. I have used "stainless steel" and "cast blast" at the same time mixing the paint as I spray. It gives a very natural look to parts. I have had natural parts next to painted parts and it is extremely difficult to tell the difference(especially on slightly rough surfaces like a differential). Blend them as best you can. Good Luck!

[Keith B.]

Re: 67 Differential Bolts / Diffy finish

I have had good success using two spray cans at once. I have used "stainless steel" and "cast blast" at the same time mixing the paint as I spray. It gives a very natural look to parts. I have had natural parts next to painted parts and it is extremely difficult to tell the difference(especially on slightly rough surfaces like a differential). Blend them as best you can. Good Luck!