Wow. This is really interesting DIY engine overhaul!
Make sure you compare the OD of the new and old liners before you attempt to insert the new ones.
Also you'll need to take other measurements so you can work out the protrusion you'll end up with when each liner is knocked home.
And I'd be tempted to turn up something to fit the top of the liners (upon which you can place your block of wood which'll get hit by your sledge hammer). .... Because without such a thing I think the liner would bite into the wood without much of the "hit" being transmitted to the liner. (If part of this device enters the bore and is a close fit inside it - I think this would also serve to protect the liner and ensure the force gets more evenly applied arround its circumference.
I will certainly be following your assembly with interest. (I've thought of trying this sort of thing myself but I'm not sure I'd have the balls. )
BTW - Are your new liners just as thin or do you think those old ones may have been bored out?
And that engine looks like its had a hard life..... judging from all the baked-on crud on the outside and the wear on the oil pump spline.
PS. I think "speed" is the key if your using "temperature difference" to ease the fit. Hence my talk of hammering them in rather than pressing.