1970 400 original engine question

[Dieselwrencher]

Hello everyone! I am getting ready to drop a small block in my 70 longhorn and I have a quick question for all of you. I have had many 69-72 chevy trucks, and I haven't seen many 400 small blocks in them. So my question is, did gm install the 400 sbc in a Longhorn type truck, or was it a 402 bbc? I know they never produced a bbc 4x4 as far as I have ever seen but am not sure about this one. This truck also has the newer style engine mounts like the 73 up trucks use, clam shell type, and not the one bolt through the crossmember like most of them had. The guy I baught the truck from said it was a sbc truck originally but I am just curious. Thanks Ryan.