Technical Determine Shock needed

My right front shock broke on my 40 Ford broke. They were on long before I got the car. I took the shock of and there are no markings on it to determine a replacement. Is there anyway to determine what to replace them with? I measured fully open 20.5” /fully closed 13” . Should I measure the drivers side in the position it is installed? The only markings I see are the patent pending 20881 and made in the USA PO11KC1G which works out to a Monroe shock but it is missing a 1 or 2 at the end. I

 

When you measure for a replacement, you need to make sure you're measuring the same way that the catalog measurements are made. Measure it fully extended, then fully compressed. Any measurement you make in the middle of travel will be useless

 

They change part numbers some times. It could also indicate whether the shock has a stud or eye for attachment.

I’d look at the often posted link to the Monroe size chart and find a match for extended length, collapses length and the correct eyes / attachment ends.

would probably just replace both sides while your there because then they will 100% act the same and you don’t have to worry about the other one failing a week later

 

Here's a list of extended and compressed lengths for Monroe shocks that may help you.
Monroe Measurements - ShockWarehouse
Just curious - what type of front suspension do you have in your 40?

 

It still has straight axle with discs. Oddly enough I was just on that page for Monroe and went in chat. I told him the extended and collapsed sizes and he said he couldn’t help me. In that list I found one perfectly sized but it has an eyelet and mine have stems on both ends when I opened it up it said it was for the rear. It is the one mark 5539

 

That is a good explanation of the 1 or 2
I’ve been to that page I posted a picture of the one with the right size but it has an eyelet mine is studs on both ends
Yes I was planning on replacing both of them was just researching when it broke. Made me have to research a little faster lol

 

I was worried about that but was measuring right base to base without the stud thanks.

 

some searching brings up a Monroe 31125 They fit the rears of a lot of rigs including 52/56 Fords

If those seem to be a bit too long from the start rear shocks for late 60's Mustangs have studs on both ends and are 17 and something extended and 10 and something compressed depending on what brand you look at.

 

Might help. 49 to 54 Chevy's have the same shock style. Unsure on length.

 

The Chevy shocks have an eye at the bottom rather than a stud.

 

All of mine had a stud. I was talking about car not truck. Sorry