have you tried lifting a 200 block? mine was a tt though so probably a bit heavier than standard.my mate did this with an xr2 and managed to take 85kilos out of it before putting two bucket seats in it.so you might get 140-160kilos out of a cos.my power to weight was 180 bhp?ton with 260bhp.so to crack 200 per ton you might need about 300bhp to start with?