Quote:

Valvoline 10-40 with a little GM EOS.

I thought about using a synthetic, but it's too expensive for a daily driver + the guy who machined my rotating assembly said it's not worth the extra money and that a good number of racers still use conventional oils. He's done crankshaft work since the early 70's, in addition to drag racing his cars on the side, so he's pretty much seen it all.


Here's what Caldwells says about GM eos:
Q:
What about using GM EOS?


A:
GM EOS contains less than 1/2 the amount of ZDDP as ZDDPLus. The concentration of ZDDP in GM EOS is diluted in a 16 ounce bottle. The proper level of ZDDP for high performance and classic cars is a minimum of 1300 PPM. To do this with GM EOS you would have to use 16-32 ounces of EOS significantly changing the viscosity of your oil and causing possible foaming within the oil.

ZDDPlus is clearly a better choice with one 4 Oz. bottle capable of raising 5 quarts of oil to a level of 1700-1800 PPM.

One 4 ounce bottle of ZDDPlus has the same level of ZDDP as 34.3 ounces of GM EOS.