Im going to be rebuilding a 420a myself soon, this is my first try at rebuilding a motor. I only thing i am reall worried about it seting the timing. After pulling the head and having the machining done im sure the cams and crank will be all out of whack. So when i reassemble the motor do i just align all the marks on the cam/crank and put the belt on? Or this thier any gears that have a 2 cycle rotation? like 360 digrees is only half way around on the internals for example. If i just align the timing marks and put the belt on I will be happy happy! :thumbsup thanks!

Yep, align the cam timing marks, while the timing arrow marks on the block and crank timing belt gear all line up. Be SURE to use 20 FT lbs of tension with a good torque wrench on the tensioner pulley bolt when tightening the tensioner plunger to the block. The pin you install through the plunger should easily pull out of the tensioner plunger when the tension is correct. Follow the links on the main page for the timing belt write ups, there are 2 of them, one is my write up. You have to rotate the crank 2 full turns before the marks will line up again. If they dont line up evenly, redo the procedure.
Always keep the crank timing belt pulley arrow around the 9 o'clock position before rotating the cam gears, as this keeps the pistons and valves from contacting. After the cam marks are in line, then you can rotate the crank marks to TDC. Always rotate in clockwise direction(looking at the timing belt side.)

Hey man thanks! want to come down and help me out with a motor swap sometime this summer? :thumbsup I finally got a garage, no more working on my car while its parked out on gratiot! }(

Hey do you have the link to your write up? I can't find it, im an idiot..

Here ya go: http://www.geocities.com/eclipsed4evr98/Timingbeltprocedure.html

Where do you live again? You mention gratiot, which i know there is one in Detroit, which is like about 2 hours or so from me. If your close, hell i'd be down to lending a hand. I love this stuff! :)