1968 Beaumont 396

Cdncarguy · Addicted!

1968 Beaumont 396

AZ69 · Veteran Member

Well,that depends on the climate and temperature(Time of year) your running it in.Cooler temps like thinner viscosity as summer enjoys a slightly thicker blend.I'm not sure about running 15\40 weight but I'm sure it would be ok.Personally I,d stick with the manufacturer s recommendation.I can look it up in my manual tomorrow.What horsepower model is your 396?

73SC · A Poncho Legend!

Many trusted Canadian Poncho big block gurus on this forum say Shell Rotella T 15- 40 diesel oil and that's what I have been using.

4SPEED427 · A Poncho Legend!

AZ69 wrote:
Personally I'd stick with the manufacturer's recommendation.

I'm with you there. Unless it's having severe use (drag strip, extreme heat, etc) I think the manufacturer knows best. Part of the decision is based on the bearing clearances from what I understand. Some of the new engines have different clearances than our old engines, thus different oils now than on our old cars.

Cdncarguy · Addicted!

Hi AZ69 its a 396- 325 hp engine , thanks

cdnpont · Canadian Poncho Superstar!

Always something with extra ZDDP if possible on a older (or new) flat tappet.

I run Valvoline VR-1 10w30, even in my roller 496.

AZ69 · Veteran Member

Good morning guys,sooo....my 1968 GM manual states that for Temps above 32.0F that either 5W-30,10W-30 or 10W-40 be used.Seems a bit of a variety of choices there but thats exactly what it states.Below freezing,but above 0.0F to use 5W-30,10W-40,10W-30,or 5W-20.And below 0.0F either use 5W-30 or 5W-20.I grew up in southern BC so for us,I always used 10W-40 for years with great success.Keep in mind todays oils are much better suited for performance and longevity.Also have a choice for semi-synthetic or full blends which I really like.They have also taken out the ash for emissions reasons,which is not good for "breaking" in new motors.So you can buy additives for that and run it for the break in time.Also have heard that not good to run full synthetic for the first 1000Miles/km until the motor is broken in.Some guys will argue well what about NEW cars.But the metalurgy in that steel/metal is a lot different then from days of old.Hope that doesn't sound to geeky.Mark G

AZ69 · Veteran Member

Concour with cdnpont,the ZDDP additive or oil with that additive makes up for the ash that was taken out of the new oil formulas.Mark

ak 67sd · Poncho Master!

Just be sure to use an oil with ZDDP >1,000ppm. For a while oils kept changing and many dropped zddp content which keeps flat tappet cams alive. Double check the bottle label. It's best to use the correct oil, and not an additive. I don't think you'll go wrong with 10w30.

ak

DonSSDD · Canadian Poncho Superstar!

I have always used a good quality regular oil 10-W-30 with GM EOS additive. I use synthetic in my new motors.

Pontiacanada · A Poncho Legend!

DonSSDD wrote:
I have always used a good quality regular oil 10-W-30 with GM EOS additive. I use synthetic in my new motors.

Yep.