Probably... not much else it could be. Still, if it's really "1/4 quart" that's 8 ounces, a full cup. You must have used a lot of assembly lube
funny had a 467 SBC with ..oil pressure problems. Pulled pan to check bearings pan and pickup had sludge. Cleaned out replaced pump used AMSOIL problem solved. The motor is 15-1 and the guy uses Q16. i have seen this fuel and alcohol cause engine oil to break down and sludge. Avgas i believe could be a problem also. That motor runs 8.80s in 3200lb nova. Freshened after 150 passes and the motor was clean. Some race oils can be a problem also. The first oil in that motor was Brad Penn
Alcohol can do much the same as you have seen to real synthetic oils. You have to be careful with off the shelf oils because they are blended to keep costs down and fit many as many types of fuel and combinations.
