Checking Engine Block

Hello all, I am in the process of cleaning and checking out my 1989 Conbrio (351W) after it has sat for roughly 2.5 years while I built my house. I found what appears to be coolant in the bilge but I can not confirm so I am looking to pressure check the block. I understand I can pull a hose after the raw water pump for supplying air to the block, I am confused as to how I can block off the manifolds to prevent air leaking out the exhaust pipe. Has anyone pressure checked their block or do you just run it on a hose and watch for leaks?

Thanks in advance!!

Either block off the exhaust pipes in the rear or disconnect the hoses going to the front of the exhaust manifolds and block the hoses. Don't put too much pressure on the block 10 to 15 lbs max.

Thanks, I will try this out.