What oil weight should I use in a 1964 f-100 with a 292?
 

What weight oil do you all use for these old trucks? I have a 1964 F-100 with a 292. I have heard that I should be using straight 30 and should try to stay away from additives? Is this true? With that being said what type of oil should I put in it?
Thanks

It depends on if the truck is using any oil. If it is I would use a heavier weight. If its not I would go with a 10w-30........I prefer pennzoil!

Weight of oil is up to you, but using a zinc additive is not a bad idea.

10w-30 is the ford norm... if it is leaking then 10w-40 is okay or even 20w-50 if it is leaking alot... especially if you live in a warm weather area.. but if it is leaking severely and oil pressure is low... time to rebuild it.... If the engine is tired don't run it til it dies, you might damage the block better to rebuild a bit early.

So how bad would it be to use a straight 30?

Straight 30w would be fine in a warm weather area where the temp is constant day and night... 10w-30 the 10 is a less viscous component that will travel through the system easier on start up.... once the oil pressure is up you are good to go...

API-SN multi viscosity with 40 or higher (10w40, 20w50, etc), no additives.

API-SN 10w30 or lower will require an additive.

If the oil has no API rating, check with the manufacturer.

You can always ask your favorite oil manufacturer which oil they recommend for use with flat tappet cams. They know their stuff better than anyone else.

Why do you want to use strait 30 oil? Oil has come a long way in the last 50 years, modern oil is much better than anything from 50 years ago.

I run 15-40 in the summer, 10-30 in winter.

I use 10-30 synthetic oil (Amsoil) year around. No need for any additives with synthetic oil I live in Wyoming, 100 degrees summer, minus 20 degrees winter. I have heard (don't know if it is true) that if you have a engine oil leak or burring a lot of oil, synthetic oil may make it worse. My engine is newly rebuilt so not an issue.

My research on synthetic oil is basically this- You may see a slight increase in oil consumption or leakage because the oil is better at lubricating parts. Even though it is is the same weight of oil, it does a better job of getting in between parts, this increases its ability to lubricate an engine. This also causes it to get between engine rings and leaks. This isn't a bad thing. This makes it a more effective lubricant, you just may have to top it off more than normal.

Any increase in leakage/burning is not going to be significantly more than with conventional oil.

I use Amsoil Z-Rod 10W-30. It's good for flat tappet engines because it has lots of zinc. As to what others were saying about synthetic using more oil, that is generally not true. It does not thin out when it gets hot, like conventional oil. Thinner oil will obviously slip past the rings quicker. Some brands had problems with extra leakage early in the development, but I really don't think AMSOIL did. They were the first synthetics to be developed for autos.

I have heard of higher Zinc content oils being recommended for older engines. Especially if you are unsure of the age of things like your valves which can benefit from the zinc. Valvoline VR1 comes in a couple weights and has a good amount of ZDDP. I think you an find it in at least 20W-50 and straight 30W. I'll be using it (20W-50) in my 223 as soon as I finish replacing the engine gaskets.

I use a 15w 40 wt formulated for diesel engines in everything on the Farm. Auger engines ,old 6 bangers to modern diesel engines. No need for a zinc additive when you run a diesel oil. Been doing this since 1983 no bearing , tappet or cam failures .

Are you smoking something?!?!? I wouldn't put pennzoil even in a demo derby car.