[Troutslayer]

I have a small block '68 with A/C original - I have since removed the A/C and put a delete plate on the firewall. I am replacing the heater core. I have taken out the two bolts inside the car on the heater box and also removed the 3 speed nuts inside the engine compartment on the firewall.

While the left side of the box seems loose, it feels like there is still something holding it on the right side (when looking from inside the car). Is there another bolt somewhere that I can't see or is there some sort of glue/cement holding this 52 year old part on?

Thanks in advance for any help.
Alan

 

[SoCal805]

I just did my HC on my 67 a few days ago.. There were 5 nuts to remove on the firewall side of the suitcase. The one closest to PS fender is "awkward" to get to but doable with a 7/16 wrench. Sounds like that is the nut you still need to remove

IDK if 67 and 68 suitcase is the same but mine has 5 studs protruding through the FW with that one on the PS being tucked into the inner fender area. The other 4 are 2 on top and 2 on bottom of suitcase. The 5th one is on bottom towards PS fender

 

[Troutslayer]

Thanks. I finally pried it loose. On the cars with air conditioning there are only 3 speed nuts on studs on the firewall in the engine compartment; 2 bolts inside the vehicle. And yes, on the passenger side, the nut under the lower hose was a pain in the butt to remove. Had to loosen the 10 inner fender bolts to get some give in the inner fender so I could get my hand and a wrench up there.
I took the a/c suitcase out last year and put a delete plate on there so it as a little easier but it would have been a whole lot easier if chevy hadn't put that speed nut under the lower header core hose outlet.
The heater core I ordered from Rock Auto wasn't an exact fit, so I will have to cut the lower hose hole in the firewall on the bottom side and make the hole bigger, or send the unit back. Aftermarket parts just aren't plug & play unfortunately.
Appreciate your response.
Thanks,
Alan

 

[SoCal805]

Your "AC" version case is different than mine (67) and you have a 68. The HC I got from RA is for a non AC SBC (link) and while the tubes were very slightly different bend it did go in my existing holes and clears my motor.

BTW, I have the same setup as you. BP 355, Edelbrock 600 cfm, Edelbrock Air Gap intake. but I have a TH350. Your 4L60E should be nice

More Information for APDI/PRO 9010337

I assume you got this one for a 68

More Information for APDI/PRO 9010333

The tubes go in before the studs engage so the up/down-L/R shuffle gets it in unless your firewall hole separation is different than what your core tubes are with the replacement unit. Mine was plug & play in that dept. My replacement HC was about 1/4" thinner than the original. Yours specs as 1/2" thicker so likely same thickness as your original. I had to bend the retaining clip tabs some to get them to hold HC snug but no big deal

 

[Troutslayer]

I got it done. Had to modify the lower heater line hole in the firewall a bit to get it to fit, but it ultimately fit. I was able to get it all back together and it works. Thanks for everyone's help.