Converting PA18A 125hp to an O320?

I have a 1952 PA18A with an O290 (D2, I think). Although it's a low time rebuild and performance is great, compression was a little low on 2 of the cylinders recently, with leakage into the exhaust. I didn't realize how hard it was to find O290 parts and support but I'm starting to worry and consider options such as conversion to an O320. I love the O290 and don't need any more performance, but like the idea of a more common engine for which I'm sure support will be better. Where do I find information on what is required to do that? What specific models of O320 are possible? Does the conversion also increase my useful load from 1500 to 1750lb? And any estimates how much that would cost (and what I could get reselling the O290)?

I had a 1954 and I think Cub Crafters had the STC.

Wagaero for the stc . they have it with or without the gross increase. Buy a rebuilt 320 outright and sell your 290 to a experimenter. You might need a new engine mount. You might just need a cabane for the increase gross if you already have hydrasorbs and the extra half inch tubes behind the baggage. The increased value of the plane should offset the cost if you do it right.

I just went throught he cub crafters O320 150 to a 160 and all the info was there about others. I have it electronacally from them for info can can forward it if you like...

converting

Oldcrowe , sorry for butting in here , but I am also considering changing out my 0290D2 to an 0320 or some at some point . Would like to see the info you have from cubcrafters if thats OK with you . Email is rcharles6943@charter.net Thanks much...... RC

For SZQ, The gross increase will need the tubes mentioned , and a larger cabane and gear attach bolts at the fuselage .There are several posts on this site about the subject if you do a search ,covers it all in detail ... RC

no problem will send when I get to the office

Yes, please send the info

Yes I'd love to see the specifics. My email is stholen@unum.com

Does the engine change require those other mods you mentioned or only to get the gross weight increase along with it? Just wondering if it's a package deal or I can consider them as separate options.

Thanks for all the helpful answers here so far!