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Ol' Grey · 03-28-2003, 05:05 PM

I may be wrong, but I'd think the 20W-50 oil would cause the higher pressure due to the thicker viscosity.

I can tell a slight difference in my car between 5W-30 and 10W-30 although it may be due to the extremely close tolerances of the GENIII SBC. For instance in the summer months running 10W30 keeps my oil pressure a hair or two above 40psi at idle. Using 5W-30 under the same conditions drops the pressure to just below 40psi. These observations have been at normal op temps.

03-28-2003, 05:05 PM	#17
Ol' Grey A work in progress Join Date: Mar 2003 Location: Marion, NC Posts: 104	I may be wrong, but I'd think the 20W-50 oil would cause the higher pressure due to the thicker viscosity. I can tell a slight difference in my car between 5W-30 and 10W-30 although it may be due to the extremely close tolerances of the GENIII SBC. For instance in the summer months running 10W30 keeps my oil pressure a hair or two above 40psi at idle. Using 5W-30 under the same conditions drops the pressure to just below 40psi. These observations have been at normal op temps. __________________ Marc Cook 1986 Chevy Silverado C-10 LWB Gunmetal Grey Metallic 5.0L HO, 700-R4, '73 12-bolt rear Long tube headers, 2.5" dual exhaust dumped before the axle. 1988 GMC Sierra SLE 4WD 5.7L, 700-R4, stock everything 6000LB winch