Hi I have a 454 630 hp blower motor what would be the best oil and what weight oil .When can I switch to "synthetic ". Motor has 60 hours on pistons and rings. Rest of motor is new. thanks

I run Mobil 1 15-50 in my procharged 502s @ 650 hp. Is this the best? I don't know, but they run great and after 20 hrs the oil is still clean. You can switch after about 20 hrs.

tHERE IS NOW TWO SCHOOLS OF THOUGHT ON USING SYN. IN A NEW MOTOR gm FOUND IT PROTECTS THE CAM AND BEARINGS BETTER (sorry about the cap lock ) and only takes a very short time to seat the rings , they use it in new motors an I use it from the start .
The Mobile staying clean is good or bad as either the motor is very clean and running right or the detergents aren't working to clean the combustion by products ect.

I like amsoil series 2000 20w50 syn.oil or mobile 15w50 and I would use it now as you have time on yours ,really any syn is just plain better than any conv. oil ..

SWITCH TO SYN. NOW save that motor

Royal Purple is great too !!!!!

Thanks everbody