The 2004R is the same length as the 350/Powerglide but I think the mount is somewhat different.
Also 700R4 is the commonly refered to designation but 87-92 transmissions are really a 4L60 which became a 4L60E in 93. The 4L60 can be identified by a large "rainbow" casting mark on the bellhousing part of the case. As mentioned earlier they are stronger than the early units.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine