Purple Shaft vs XE Comp Cam

If the engine is apart, make sure the pistons are really 10.5:1 as they are sitting in your engine. Most are closer to 9.5:1 unless the engine was blueprinted in it's past build. I think there's room to improve what you have, so i wouldnt call that MP done. But for what you're doing I think the XE268 is perfect. The Lunati 268 is another good choice. The Lunati is a little more aggressive in terms of rate of lift over the Comp. Both would need springs matched for them.