The Dodge Challenger Message Board

What grade of oil should be used in a rebuilt 383? I have been told 10w 30 by some and 10w 40 by others. Any suggestions?

USED 10W-30 for the first 500 miles and then changed it to 10w-40.

better pressure and better in the summer heat!!!

This is from the 1970 Challenger operators manual.

If the car is mostly used above freezing then use a 20w-40, 10w-30 or 10w-40.

If it is used occasionally in temps down to -10F use the lighter of the two above.

HOWEVER!

Vehicles equipped with "optional high performance engines" should use as heavy an oil as possible that will permit satisfactory cold starting.

SAE30 or SAE40 single grade oils. 20w-40 or 20w-50 multigrades.

Never use a 10w-30 or 10w-40 if the car is "driven in competition or other forms of maximum performance operation".

So now you know!