Morning young man...
If it was my choice, I would not be looking to layout some $340 plus to try and save the old system...and wonder if the tanks are really that good....
Any reason why you need 3 HP ?
I have this unit in my shop and it works great, is mobile if necessary and its a reasonable price...
https://www.harborfreight.com/29-gal...sor-58507.html
Just my 2 cents worth...
Have a great year...