yes the truck tranny and car trannys are completely different. the truck trannys dont have the TCM issues u have with the car stuff... If you where to find a car tranny u would have to make the ABS/ ESP/ TCM/ toner rings etc work with the rear u have which is a ridiculas amount of fab work. The truck stuff will work fine with a 8.75 b/c you dont have to use the stuff mentioned above.
However the truck trannys cant take the same abuse the car NAG1 trannys can... but if u are just gonna run stock 5.7 or evern head and cam it you should still be fine... I have a 11K long blovk sitting in my garage right now for sale if u havent found one yet... I live in VA.