94 S10 4WD heater core leak!!

how does one change out this one, done several, but not looking forward to this!! any ideas?

i'm not sure if i'll be of any help, but i just did mine (93 s-10 pick-up)... it wasn't too bad once all the bolts were out..... it's right up against the firewall, but it was really awkward to get off some of the bolts. it took a few hours, but not bad. i just bought a haynes manual, and went for it. I don't know the changes that occured in 94... but i do know there were quite a few... i hope i helped anyway!!!