I would not worry about upgrading the 496's if you buy a Baja with those engines. Raylar has Baja customers all over the country with our kit upgrades and some now have over 400 hours on their 496 engines with absolutly no problems. Not sure what other "build up" types the other poster was talking about for 496's, but with over 700 - 496 engines out there running Raylar kits, I don't think reliability will be your issue.

Best Regards,
Ray @ Raylar