I have a 272 y block that was rebuilt a few years ago (probably less then 5000 miles) and I was wondering what grade of oil I should be using. I having been using 5w-30 on the advice of valvolines headquarters but I’m worried it might be to thin. Should I be using 10w-30? Any advice?

You will get a lot of suggestions as everyone has a different opinion.  I am using Valvoline 10-40


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

If your oil pressure is good, then the 5w30 is fine in that regard.  Most 5w30 will be formulated for newer engines which means that it will not have the suggested amounts of zinc and phosphorous - check with the oil manufacturer.  If that is inadequate, then there are additives to bring it up to good levels or you can halve the oil change interval, or simply use an oil that is adequate right out of the bottle.

10w40 does seem to be about the average used in Y-Blocks.


Lawrenceville, GA

I use Brad Penn 20W50. Probably a little overkill but it was at the suggestion of the guy who built my engine. I am considering switching to Penn 15W40 next oil change.

Durham Missouri

On the oil test website (540RAT) he shows that Valvoline Conventional 5W30 is more than adequate for our engines without the use of any additives. I've been using it for years with no problems. My 312 will idle hot at 35psi and run 50 psi above idle. I can usually find it on sale for $3.00 a qt. Dave V

SE Wis

For the last 20 years I've run Mobil 20/50 with a Zinc active with no problems.I change filter every 3000 miles and top off oil and active, I change oil every 8000 to 10,000 miles.    

Hi guys, remember Ford wanted you to run 20wt, 20-50 is to thick

Whether 20w50 is too thick will depend on your local climate, bearing clearances and / or wear.  It certainly is an option to use.


Lawrenceville, GA

Eye-opening revelations learned from that Rat site:
Zinc, etc. content is irrelevant. Only thing that counts is demonstrable wear protection. Also, oil volume is more important than pressure. Engines with excessive clearances may possibly benefit from higher viscosities, but I no longer worry about pressure as long as it exceeds 10 lbs. per 1000 rpm.

6 VOLTS/POS. GRD. NW INDIANA

Howmuch zinc additive should I be using?

Also, charliemccraney, not sure if you know it, but your sig photo doesn't show up:




1957 FAIRLANE 500