Here's a look at the dipstick modification.
The tube needs to hug the block side for a bit to clear a primary tube before kicking out and curving back up again around the flange.
Take note of how close it is to the Schumacher mount, you MUST install the dipstick tube AFTER threading the bolt through the mount. (ask me how I know)
Here is an extra tidbit about using MP mega-blocks with factory exhaust manifolds. The yellow arrow on the far left shows where the oil drain-back kick out must be ground for clearance. The middle arrow is where the water jacket bulge had to be ground at the top for clearance, and the far right arrow happens to be where a Cometic gasket tab needed to be bent down.
Whats with the yellow box on the right? Mega-blocks have bulged out water jackets to accommodate the big 4.5" bore. Because of that, common stock starters won't fit and you MUST use a mini-starter regardless of headers or manifolds. (Again, ask me how I know)
Hopefully these notes and pics saves somebody some headaches down the road, it always pays to test fit things before putting them in the car.