I am going to go through the P-40 lineage using Curtiss figures. Adjust as people see fit.
P-40 Tomahawk I gross weight 6807lbs (120 US gal fuel), 357mph at 15,000ft. Initial climb 3080fpm, 15,000ft 5.3min.
P-40B Tomahawk IIa - GW..........7352lbs (120 gal), top speed 352 mph at 15,000ft, initial climb 2860 fpm. 15,000 5.1 min ( I know, it doesn't work)
P-40C Tomahawk IIb - GW..........7504lbs,(120 gal), top speed 345 mph at 15,000ft, initial climb 2690 fpm(climb to 15,000ft not given)
P-40D Kittyhawk I - GW...............7787lbs, (120gal), top speed 359 mph at 15,000ft, initial climb 2580 fpm.
P-40E Kittyhawk I- GW.................7952lbs, (120gal), top speed 366 mph at 15,000ft, initial climb _____. 15,000ft 6.25min.*
P-40E Kittyhawk IA- GW..............8100lbs, (---gal), top speed 354 mph at 15,000ft, initial climb 2050fpm. **
P-40K Warhawk --- GW...............8300lbs, (120 gal), top speed 362 mph at 15,000ft, Climb at 5000ft was 2160fpm, Climb at 15,000ft/1650fpm.
P-40F Warhawk I -- GW,..............8509lbs, (120 gal), top speed 364 mph at 20,000ft, climb ___________.
P-40L Warhawk/Khawk II, GW...8120lbs, (120 gal), top speed 370 mph at 20,000ft, initial climb 3300 fpm.
P-40M Warhawk -- GW...............8319lbs, (120 gal), top speed 360 mph at 20,000ft, initial climb 2050 fpm. 15,000ft 7.2 min
P-40N Warhawk -- GW..............7740lbs, (??? gal), top speed 378 mph at 10,500ft, 15,000 6.7 min (stripped version, four guns, WEP)
P-40N-25 Warhawk - GW............8354lbs, (159gal), top speed 350 mph at 16,500ft, initial climb 2120fpm, 14,000ft in 7.3 min. (heavy FB version, six guns)
*Standard US performance figures for climb use military power for climb (3000rpm for the Allison) for 5 minutes and then max cruise (2600rpm for the Allison) for the rest of the duration of the climb and do not accurately reflect combat capability.
US often tested at standard altitudes like 15,000ft and not at the altitude that gave best performance (like 14,000ft or 16,000ft).
** I don't really know what was going on in the two different P-40E versions.
All weights are for standard Gross weight, clean with the 'standard' fuel load which is NOT full internal fuel. These are also the weights for a specific airframe pulled off the Curtiss line, The P40F for instance was 109lbs over guarantee weight. A few P-40s were up to 29lbs light, others were over. Any production aircraft could vary 2-3% in speed and still be accepted
I will also note than on the P-40Ls and the early P-40N they pulled one internal fuel tank out so the range really took a hit without the external tank, all figures do not include external tank. External tank could be worth 20mph on speed.
No information on if they tested clean or with brackets/braces.
A note on the P-40D,E and K, the change in critical altitude was change in the power rating from the earlier engines, They were allowed to use higher boost at lower altitude (not WEP) in military power and so made 1150hp at just under 12,000ft instead the 1040hp at 14,300ft for the earlier engines, however the newer engines would still make 1040hp at 14,300ft.
Some of this depended on exact intake manifolds and flame arresters/backfire screens.
If the pilots on the older airplanes used more than book boost (there were no pressure limiters) they could (and did) get the 1150hp at the same altitudes the -39 engines did and more than book power lower down.
Also note that may of these planes had two critical altitudes, one at high speed level flight (max ram) and one for climbing (140-150mph/min RAM) and they were thousands of feet apart.