This ought to look great when its done! There are some 'warts' with every 1/72 Blackbird kit that's available. Viper Enforcer did a great comparison post back in 2010 on them:
From what I’ve learned, the Monogram kit is slightly better; primairly in the main fuselage, though the cockpit sill opening is too wide. Tony Landis and I were talking about this last week when I was doing some business at NASA. He gave me a but-load of SR-71 and ACTIVE F-15 reference material. As we talked about kits, he mentioned the Monogram SR was one of the better ones in 72nd, with Italeri a close second. Here’s a synopsis of what I compiled so far:
The two best 72nd SRs are the Monogram and Italeri kit, in that order. Both have some accuracy and shape issues, but overall Monogram has the better Blackbird.
Monogram SR-71:
Monogram has the best lines for an SR, as the fuselage and spine are nice and straight. It also doesn’t have a droopy/sagging profile problem in the lower aft fuselage. The wing fillets and engine nacelles have the best proportions of any kit. The wing corrugations are also the best.
The upper vertical tail straight profiles should be more rounded. There is also a beef up plate on the outboard of each vertical tail which should be removed or sanded down. This might have been taken from one of the test SR-7s that had similar plating, which was not carried over to the production SRs. The wingtip camber is decent, but could have been a little better defined.
The Monogram SR has the most accurate cockpit/canopy side profile out of all the SR kits. The only problem is that the cockpit sill (opening) dimension is too wide, resulting in a noticeable bulged out cockpit area. This gives a pudgy appearance to the cockpit fuselage sides, when viewed from above. Also note that the canopies do not fit all that well in the closed positions. Some adjustments will be in order to get them to fit well.
The MLG, MLG wheels, and wheel wells of the Monogram are more accurate (though a bit soft) and better detailed than Italeri's gear/gear wells. The wheel wells do lack depth though, but then again, so do the rest SR kits.
Monogram's SR kit is the only one to have a detailed cockpit that actually looks the part. They also include two well detail crew members. Even so, the seats could use some improvement, but are still better than the unrecognizable chairs that come in the other SR kits.
Engine nacelle contours are a bit too subtle, as they should taper a bit more sharply toward the nose cones. This will not be an easy fix. Monogram's Exhaust nozzles are set partially closed, which in the powered off mode should be full open. The interior nozzle detail is lacking and not near as well done as Italeri’s. Monogram really dropped the ball here.
A D-21 drone is included and has a similar nacelle contour issue.
Italeri SR-71
The canopy side profile is flat out wrong. It's more representative of an A-12 than an SR-71. Italeri's SR would serve as a better basis to make an A-12 than an SR-71.
The front windscreen wedge (a later mod to help dissipate heat) in missing, but then again it’s missing from the rest of the SR kits. There is practically no raised cockpit surface detail and the console and instro panel decals provided, are a joke. The instro panels have some raised detail, but they pale in comparison to Monogram’s.
Italeri's SR nose is short, being somewhere between the A-12 and SR-71. The nose is also too shallow for an SR and the forward RWR antenna fairings are totally wrong. The lower aft fuselage (aft of the MLG wheel wells), has a drooping/sagging profile, which will be no easy fix. The forward fuselage spine profile is off and the upper aft fuselage has a much too aggressive contour towards the tail cone.
While the wing corrugations are for the most part represented, they are somewhat crude and not as near as nice as they are on the Monogram kit. Wingtip camber is well done and probably the better of the two kits.
The main gear struts and wheels are tooled quite nice, but lack detail and are not all that accurate. The wheel wells are ok, but are too shallow and again are lacking detail.
Italeri's SR has the worst fit out of the lot. The fit is real bad of the radome and tail cone to the main fuselage. While it may have the worst fit, it does have the most options. The SR-71B 2 seat trainer version can be built from the same kit. Italeri also offers the YF-12 variant in separate kit form, though it's real hard to find.
The Exhaust nozzles have a slight closed configuration, though still more open than Monogram’s. The Italeri exhausts are the only ones that have ribbing detail on the inner nozzle segments.
Hasegawa SR-71
The Hasegawa kit has some real shape issues with a narrow canopy (poor upper profile), sagging rear end, over scaled nacelle spike cones, and the fuselage cross section is proportionally to narrow. The landing gear though well tooled, is not all that accurate.
Overall the Monogram is more accurately shaped than the Italeri kit, as well as better detailed. It’ll serve as a better basis for an accurate SR-71 in 72nd, though it will need some work. Until some new aftermarket sets are made, to build the an accurate SR it’s going to take parts from the Italeri (like the exhaust) and some scratch building to turn out a truly accurate SR. That is, until some new aftermarket sets are made.