49 flathead oil?

I just got a good running 49 ford flathead and I going to put some new oil in it. Its all stock. Which oil do you guys prefer? Im sure other have more experiences with these engines, im just learning.
thanks

 

I have been running 20-50 in my 105K never been overhauled flathead.
Change the filter often.

 

saw a post a couple of days ago sayin to change your oil every 1000 miles or less some guys do it every 500

 

Stick with 20W-50. I've heard lots of different weights, but most guys seem to use 20W-50, good for most weathers.

Flatman

 

I go with whatever is on sale. I treat my flattie as if it was a modern engine. Change your oil whenever you get a fire under your ass. Thats what I do.
Jack

 

The first thing you need to know is, has it been running with detergent / modern everyday off the shelf oil.
If it’s old and crusty inside from running non detergent, detergent oil will beak all that shit up and send it true your bearings and ......... you know, not good.
Can you ask the guy you got it from?

 

Im not sure if the oil is non detergent or not. I could try to ask who I got it from. If it is non detergent oil how can I switch over without wrecking it? If I put normal detergent oil in it and run it very little will this flush it or would the damage happen that fast? It probably would break down over time correct? So what is the safest method if switching over other than a rebuild?

 

How to find out, you do that. If it turns out it it has never had detergent oil, then pull the pan. There'll be a couple of inches of sludge in the bottom of the pan. Clean it out good, check the screen on the oil pump, and before you put the pan back on take the intake manifold off, chean all that gunk out of there, it's best to dig it out with a spoon and then with solvent soaked rags. Before you put the pan up for good, flush from the top with kerosene. NOT GASOLINE. After that, use 10-30, run it for a half hour and then change it again. Keep an eye out, when it looks dirty, change it again.,, and again,, and again. When hot weather comes around, change to 20-40 or 20-50.

 

i have a 49 ford and i have always ran casterol sae30 the original oil weight and a stock filter from dennis carpenter in charolette nc. that has done me right for 6,000 miles any way.

 

The advise that I took was to throw the oil filter assembly as far as you can and change the oil more often. Bob

 

Listen to "Flatman"

 

20 - 50 W. best balance for oil pressure and bearing cushioning IMHO. Remember our flatheads arent revvers - liter weight oil wont make any perceptible difference, so Id rather have the protection.

Rat

 

use a diesel grade ("C") rated oil in older engines, I use 15W40 fleet oil, change every 2000 miles.

 

Yup Castrol 20-50 every 1000 miles, works for me.