When I first got my truck I did not have a hand book for it so I used 20w/50w oil to do an oil change. Since then I have obtained a hand book which indicates the use of 10w o 30w oils depending on the ambient temperature. I have looked up on the net but all the oils seem to be for post 1990 cars.

So to my questions. Is any 10/30 oil OK or is one of the synthetic ones the better wayto go, is the modern engine stuff OK for the older Y block?

Regrds Peter

Hang loose and enjoy the ride.

Brisbane Australia

My '55 has used Trop-Arctic 10W-40 since the car was new.  This was actually the first multi-viscosity oil introduced and goes back to 1954.  Tore the engine down in 1990 and was super clean with minimal wear.  Crank went back standard and the bores cleaned up at 0.020" over.  The car is still on that oil today but it's the older rated stuff.

Just do a check for the zinc amount in the oil you're planning on using and if the zinc is low, then just consider a zinc supplement to add to the oil.  Not all the SM rated oils reduced their zinc levels so you'll have to research this.

And as HotWrench mentioned, this topic has been talked about extensively.  Just do a search for 'zinc' on this site and others and you'll have a lot or reading.

Lorena, Texas (South of Waco)

I used valvoline 20w50 in the last motor without adding any additives. Everything looked good after about 11k miles. I'm using the Valvoline VR1 20w50 in the newer engine. My engine is geared more to performance and 20w50 is better suited to the clearances I'm running. If yours is stock it's probably best to go by the book.


Lawrenceville, GA

There is no problem running 20-50. I run it in my 302 powered street rod. I would think it would add more protection than the 10-30

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

well since my engine is very very worn and my rigs are all bad and i have a leaking rear main seal i use valvoline racing straight 50w oil it builds oil pressure when the engine is running at about 150 degrees. Oil pressure is only 15 pounds or so when hot so it fills gaps better than using any other weight for now but i am rebuilding the engine soon

Not my dads 57 Fairlane nor my grandfathers, young guns are taking over ! REBELLIOUSENGINEERING.COM

Thanks guys, spent most of the day reading thru old posts. Found lots of interesting information to help the decision making easier. Decided to go with the 25w50w and an additive. One thing I have learnt is that oils aint just oils.

Once again thanks to all. Peter.

Hang loose and enjoy the ride.

Brisbane Australia

g'day peter

in the mainline i use 20w/50 usually valvolene & for us aussies stp oil tratment is very good i put it in at every change my engine has now done 7000 miles & looks good inside.

moz. geelong victoria australia.

graduate 1980, bus, truck, car, hot rod, boat, submarine, hovercraft, hydrafoil, firetruck, mobile home, jet, helicopter, cruise ship, motorcycle, bicycle, santa's sleigh, clock, alloy bullbar, alloy fuel tank, lens, dr who's tardis, matter - anti matter warp drive buffer & y-block lover

Very good article on this in this month's issue of Muscle Car Enthusiast.

Frank/Rebop

Bristol, In ( by Elkhart) 

In my 59 I use Valvoline 20W50 racing oil with Lucas oil additive. I havn't had any problems.

John F

John F

Ballwin, MO