A lot depends upon the condition of your 216.
Chevy spec'ed straight 20w back when it was new and that was good for most all temp ranges.
A lot of folks run either a 5w30 or 10w30 on a newly rebuilt engine. Some run a straight 30w, and some run 15w40. On high mileage engines it's not unusual to run 20w50.
The bottomend of my 49 216 is of unknown mileage but based on the original odometer I guesstimate around 100k miles on it (the head was rebuilt approx. 10k miles ago) so I run 15w40. I'm avg'ing approx. 12psi at speed and perhaps 5psi at idle when warm. I tried 20w50 to see if the pressure would pickup some and it didn't and the engine was louder w/10w30. So I settled on 15w40 which also happens to be less expensive, which works out good for my leaking rear main seal too.
You may have to experiment around to find the best grade.
re.tranny and rearend lube. I use an 80w90 GL4/GL5 rated lube for my tranny and rear. Both run quiet and seem to work fine on it.
Good luck
Dave
Last edited by Volfandt; 04/30/2015 12:46 PM.
