My 1966 Corvette manual specifies 10w30 engine oil.(327cu 300hp) Can I use HD 30 instead?I live in southeastern Pa.and drive very little, especially in winter.

.. I would say it depends on the overall health of your engine.. If it is using or leaking a little, I would at least use 10w40,that's a good all season oil... I have changed my 63' 360 horse F.I. original over to 20w50 synthetic and have not had any cold start problems, although, I never hit the gas, as I'm cranking, until I see the oil pressure coming up...I've forgotten how old my battery is and the car still does 20+ mpg highway.. HEY," If it ain't broke, don't fix it " !