I did some simple testing to check the straight line speeds of different ships from different factions. Method was simple
1; Start at the most forward part of the spawning zone
2; End at the edge of the map on the enemy side
3; Use the in game timer
4; Boost/Rush/Etc as optimally as you can.
Results;
Avenger, IN, Reload (160 Speed) 3:20~(This includes the combustion boost from the execution command)
Executor, Chaos, Reload (160 speed) 3:45~
Slaughter, Chaos, Reload (240 Speed) 2:20~
Dying Sun, Drukhari, Reload (240 Speed) 2:25~2:30
Vaul, Corsair, Runic (280 Speed) 2:25~
Vaul, Corsair, Reload (280 Speed) 2:20~ (Due to the timing, your last boost comes off cooldown right as you reach the finish line, So this probably deserves to be a little lower)
Killa, Ork, Reload, No Red Paint (160 Speed) 4:10~
Killa, Ork, Reload, Red Paint (160 Speed) 3:25~
Space Marine, Cruiser MKII, Reload (200 Speed) 2:50~
Tau Protector, Custodian, Reload, Experimental Manifolds (185 Speed) 3:05~
Tyrannids, Corrosive Clutch Devourer, Reload (160 Speed) 3:30~3:35
Necron, Cairn, Reload (160 Speed) 3:05~3:10
Necron, Scythe Reaper, Reload (200 Speed) 3:05~3:10 (Due to the timing, your last teleport comes off cooldown right as you reach the finish line, So this deserves to be lower. 5-10ish seconds probably)
Necron, Cartouche, Reload (240 Speed) 2:40
And a imgur gallery link with finish line snap shots; https://imgur.com/a/e9W1J06