Technical Oil change on a 336 GMC big block

Sorry everyone, but a total newbie here with a 1958 GMC pickup. It's got a 336 big block that I believe started out as a Pontiac 370 but has a smaller bore from when GMC reworked this motor for their trucks.

I searched the site but I will be the first to admit that I suck at searching lol. My question is a simple one, what type and amount of oil is used for this motor? The parts stores computers don't go back this far!

Thanks, Carl-

 

It is a Pontiac motor so, with filter 6 quarts.
As far as oil 10/40 for summer Brad Penn or similar oil with ZDDP.
A lot of guys are using single grade diesel oil, but I was told by a long time diesel mechanic that those oils have a special detergent in them that might not benefit older gasoline engines.
If you can't find an oil with a higher ZDDP level just buy the additive and follow the directions on the bottle for the amount of oil you are adding it to.
KK

 

You can find some useful information on the Old Car Brochures website: http://www.oldcarbrochures.com/static/NA/GM Trucks and Vans/1958_Trucks_and_Vans/dirindex.html Besides a brochure they also have an owner's guide and a features bulletin with lots of good info.

 

Thank you very much, I think the dipstick is the wrong one for the truck...shows no oil at all . So I'm going to change it and put the right amount in and of course see if it shows. If not I'll get the right stick.

I found some manuals on Ebay and they are on their way.

Thanks again!

Carl-

 

Isn't Valvoline VR-1 higher zinc. Think it's similar to Brad Penn but probably easier to come by.


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I picked up Castrol 10w40 and some hy-per lube Zinc additive. Pricey at $18 bucks a 12 oz bottle though. Thanks again for the input folks!

 

Since its a stock engine with very weak valve springs and little valve lift, you can get by with less zinc additive. 1/2 bottle per oil change will be plenty. The new high lift fast acting cams and heavy valve springs are the engines that need better treatment.

Any 10-w-30 or 10-w-40 will work, if it's got a filter use a NAPA premium or Wix brand, both very good filters. Diesel oils are for diesels, since 2007 the zinc levels have been dropping just like gasoline oils, just not as fast so there is really no advantage to using them.

Joe