I have owned a 65 7ECA, 72 7GCAA, and presently a 73 8KCAB. I seem to remember the climb performance and possibly useful load being better on the 7GCAA than the other two. The 7ECA was with 0200 continental and obviously under powered but a sweet fling aircraft and at the time carried myself wife full fuel and all camping gear as well as newly bought items from and excursion. The 7GCAA was fixed pitch with 0320 lycoming (150 HP) engine. This aircraft seemed to perform better than my presently owned 8KCAB. Between the 7GCAA and 8KCAB I owned a 220 hp M4 Maule, maybe this is skewing my recollection. The 8KCAB has had the constant speed prop removed and a fixed pitch installed. The current weight and balance shows an empty weight of 1235.25 lbs. The aircraft does not have metal spars or the new gear that would increase the gross for normal category to 1950, so my gross remains at 1850 and therefore I have a useful load of 564.75 lbs. Fuel fuel is about 260 lb I weight 180 and my wife is around 130 totalling 570 lbs. or 5.25 lbs over gross. If I remember right the older 7ECA and 7GCAA aircraft had a lower empty weight. I think the 8KCAB is a heavier and I know stronger aircraft. The 8KCAB has a shorter wing but at the same time more surface area. One noticable difference is the flexibility of the longer wing 7 series and the 8 series aircraft. If you were to rock the wings of these aircraft up and down the 7 series will send a noticable wave down the wing where the 8 series is solid, at least with the aircraft I owned. Regardless of the low loaded performance and low useful load the aircraft is a pleasureot fly, quiet, economical, and just plain fun. I fly mostly for recreation, I fly daily, and 99% of my flying is acro. Because of the primaily acro usage I keep the fuel level down to less than 1/2 tanks, and I am the only occupant, the aircraft performs perfectly well. If I take an occasional trip, which is the nice thing about this aircraft, it is versitile, I simply lower the fuel level and make more fuel stops. I did call ACA prior to purchasing this aircraft to get, as you are, info on what I should look for beyond the usual. I was not told much that helped but in the defense of ACA there are so many bulletins and AD's, many due to prior manufactures that it would be difficult to list everything. I believe the major issue I found was that under the front seat and just under the lift struts there are supposed to be sheet metal cross members (2) which are use to secure fabric (like formers), these cross members were originally attached simply by tabs the fit between the longeron and the fabric. The fabric was then pop riveted to the cross member. The problem is that these tabs break and no longer provide the rigidity to allow the cross member to support the fabric. This is, to my knowledge, not an AD, it is a bulletin. The fix is to reinstall new cross members and attach them to supports that will be riveted to the original standoffs between the frame and the lower stringers. This is not as bad of a job as it might sound. The job does require some fabric work and removal of the floor boards but in my case some of the frame support members were missing and the fix required some welding. These were not broken or anything of the sort that would indicate a frame problem. No, after talking to ACA we came to the conclusion that Bellanca simply did not install them. I am gathering this is was not an uncommon problem with order manufacturing controls. In any case my point is there are many thing to look for and it is extremely difficult to list everything you might find. After a year of flying and what I would call sprucing up (TLC) the aircraft is in excellent condition with only a few other things I would like to do. Definately pay attention to the amount of current flying on any aircraft you are considering for purchase. My 7GCAA was not flown a lot and began making chips as soon as I took possession. The engine had to be majored.
