Yep, definitely get the re seal kit...cheap...everything will crumble when it comes apart, plus it will work nice when you get it back together.

Had lots of trouble getting a core that fit, so be careful of the Mexican/Import/whatever repo's. They look very similar, but the tubes are always bent a little bit off and it won't fit...check this carefully.

I think it comes out from the inside, but mine has air so maybe different. Not a real fun job, but it can be done...just remember to keep track of the screws and NEVER force anything or you'll break something and hate yourself. 35 year old plastic is very unforgiving.

My 68 BB w/o air heater core was leaking two yrs so I ordered a new core. It came out from the inside & it's a bitch...takes time. So I ordered a air/heater kit & installed it instead. I've still got the new core...make me an offer & it's yours with my blessing.

Alan

If you are going to do the core change yourself, take the heater core out first, go to a radiator repair shop and order one from them, sometimes the tubes are not right, or may need bent to fit. If you get one from Ebay and it needs bent to fit, and it leaks, guess how lost time and money? 

It's not a fun job, and it should come out from the inside with lot's a work. Mines a 1982 small block.

You may want to get a local mechanic to do the job for you.

Good luck and have a great day!

xfire