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The stock primary gearset for a Turbo Optima appear to be 32 dp but something makes me think they're not. Do these cars require special pinions or will 32 dp ones work?

Turbo Optima's gears are metric...Mod .8 but it's close enough to 32dp that they can be used together.

Okay, thanks Phin. I've done a bit more research and found references to "1 Mod", and ".6 Mod" gears as well. Do you know; is this the tooth pitch (in mm's) as measured at the pitch diameter? Not sure but I think 32dp means 32 teeth per inch as measured at the pitch diameter. I recall with screw threads, imperial measures the number of threads per inch while metric measures the distance between each thread. I thought perhaps the same logic might hold true for gears. Anyway, I'll throw a 12t 32dp pinion in there and let er rip. Thanks again.

Module is the pitch diameter divided by the number of teeth.

Mod 1 gears are typical for 1/8 scale cars and were used on a few earlier Kyosho 1/10 cars like the Beetle, Scorpion, & Tomahawk. Mod .6 is what Tamiya used...you'll hear it called metric 48p even though they're not really close at all. Mod .6 has about 42 teeth per inch. Unlike Mod .8 and 32p they don't mesh.

“Metric 48p” do mesh with 48p for a couple runs when your 12 years old and don’t know any better Ask me how I know

GoMachV wrote: ↑Sat May 26, 2018 9:13 am “Metric 48p” do mesh with 48p for a couple runs when your 12 years old and don’t know any better Ask me how I know

Or, when you're 58 and don't know better.
On that Mid runner I just finished, I wasn't aware that the factory spur was metric so I ran it once with a mismatched pinion and boy was it noisy. Even my dog Sadie went running for cover. Fortunately, I stopped and diagnosed the problem before ruining any parts.

Anyway, thanks Phin for the explanation.