im changing cam shaft hava few Q's

[pissonNOS]

what all am i going to have to take out ? just my rad or will i have to take out the grill its a 69 gmc grill if that helps? and how big of a job is it on a 307? im apprentice mechanic for forklifts but havent done too much on the v8s

[Green Machine]

I think it will clear the grill, at least it did on my 68 chev when I did it IIRC. If you want to measure, the cam is 20 1/2 inches long, the timing cover mounting face on the block is where you need to measure from.
You will need to loosen the front of the pan anns several bolts back to get the timing cover removed/back on. Best to remove pan for a leak free job, but I have done it before, just reuse old front pan seal as it is already compressesd if not too bad shape. Trim/grind a little off the ears on the timing cover where it meets the pan and block and use some good rtv(not too much) in the corners and entire front rubber and you should be ok.