Can anyone set me straight on this? Some say the inside half of the suitcase and evap.core are the only diff.on a big block, looks to me that both sides are diff. and not interchangable. Thanks Mark

The outsides of both the BB and the small block are the same. The inside cases are different shaped, to give the BB a little more clearance from the exhaust manifolds

Do you know anyone thatdid change only the inside for big block clearance. I have a big block and small block case for a 69 camaro, I was told, sitting on the bench and the angle on the big block case is diff., leans away from the engine more then the small block for more clearence, tried to interchange halfs, angle is diff., wont work. Maybe I don"nt have camaro cases. Mark

I dug out the 69 parts book and there are three part numbers for 69 evaporator halves. Two for small blocks, and one for big blocks. The outer half of the BB housing is missing from the parts book but it appears to be excluded since they list the other outer box as 69 Camaro (exc 396) inlet (17.95), so maybe they are different, although they appear to be very similar visually. The passenger side small block half is pn 3015520, the inner half of the SB box is pn 3018791 , The passenger side big block half is not listed, the inner half of the BB box is pn 3018799. Can't cross these numbers over the BOP to see if the Firebird parts are the same thing or not.

I found a picture of a BB housing and the only visual difference I can see is the top of the boxes where the two halves connect appear more squared off on a BB box, than on the small block ones.

Heres one on Ebay:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7960949628&category=33547

Guy must be expecting big bucks, its a private auction. The compressor hose end is mangled, but the evaporator and housing don't appear to have any visible damage.

http://i14.ebayimg.com/01/i/03/9b/b1/f8_1_b.JPG

http://i8.ebayimg.com/01/i/03/9b/ag/87_1.JPG