I'm looking for advice from those that have "been there, done that". I have my heater box and core off the car because of the lower inner cowl that I am replacing. My neighbor says to replace the heater core now since I have it out because it is a PITA to replace when they go bad. What do you guys think? How often do these things go bad? Mine look like it is in great shape. Are the new ones built as well as the originals?

...My neighbor says to replace the heater core now since I have it out because it is a PITA to replace when they go bad. What do you guys think? How often do these things go bad? Mine look like it is in great shape. Are the new ones built as well as the originals?
I would agree with your neighbor. Relace it while it is out. I bought a replecement heater core from Autozone for $17 and this included a lifetime warranty. As for the new ones being built as good as the originals? Probably not, but then my original was 36 years olds so I would say it was due.

I chose not to... when I fired my motor, I just happened to notice some water dripping out the firewall seam after it ran for half an hour. Inspection showed the solder joint on the lower tube musta broke when i worked the hose back on.

Replace it.

While I've heard stories about new cores being too thisn, then one i bought from cpomusclecarparts was an exact duplicate of the original and only cost fifty bucks.

I'd replace it. I'd also consider a big-block style heater core and box as long as you have it apart this far. You won't regret it.

BPOS,
What's the difference between the bb and sb cores and boxes? I live in SoCal now and me next duty station is probably going to be in Fort Worth, so I don't need heavy duty heating, at least for the next few years anyway.

the small block case brings the hoses out right at the engine, big block case moves em towards the outside of the car abouta foot

Jim,
Do you have a link to the site you bought yours from?

Change it now. It is a PITA to do it when you "have" to. I changed mine about 8 years ago. I changed cams last summer and over twisted the hose connection getting it off.

Come time to fire up the engine for break in... small geyser from the heater core connection. It's bypassed as of now, but I will change it (again) at some point.

Going to autozone today to get my new core, thanks for the input guys.

Just another note:
Take your time with the hoses and make sure you are puting the right sized hose on the right nipple. You'll wanna force it on but this is where you can crack that new core real easily. Then you gotta pull it all back apart and that sucks!

Because of the difficulty of changing the heater core, I would also take the new core to a radiator shop and have it leak tested before you install it. I recently purchased a new core from Kragan that had leaks in the core. I brought it to a radiator shop because the outlet tubes needed to be relocated slightly and they discovered the core was defective.

Jim,
Do you have a link to the site you bought yours from?

Sorry for the delay, gunner. The site is: http://www.cpucarparts.com
The owner's name is Brian. It's a smallish outfit right around the corner from where I work. I've just started using them this year, and am finding thier prices average near 15% less than D&R or Ricks.

Thanks Jim,
I wound up going with a local outfit here. Got an AC/Delco unit for ~$50. Thanks for the advice woody, I'll have them pressure test it before I pick it up.