First thing I would do is plumb in a temporary gauge under the hood to verify the actual oil pressure.

Second thing I'd do is drain the 10w-30 and put in 15w-40 or 20w-50.

All of my cars use one or the other. The Cadillac has been using it for 23 years.

I've put nearly 3000 miles on my '50 216 (non rebuilt) in the last year and a half and it's had 20w-50 in it the whole time.

I should note that the oil pressure goes to 30psi at startup but drops to 15psi when driving and idles at about 7 or 8 psi.

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)