When you say VXi do you mean the twin cam often called red top or C20XE? if so I would say if in ok condition the bottom end will be ok at those levels. I have this engine and it ran in standard form with Stage 1 Swindon cams and was good for about 180. Had it rebuilt by premier power, head has work done, bottom end rebuilt and balanced, lighter flywheel but same cam and standard valves and it went to 220. so head work and new cams should be close to what you are looking for but pistons may need pockets cut. talk to Stuart at Premier Power and he will help, there is a VX enthusiast on his team