Getting ready to perform a head gasket job as many others have done. However, having seen a couple of posts from folks tending to lean towards block damage versus head gasket..I'm biting my nails. Was wondering about pressure testing or other test kit procedures to verify head gasket or block cracking...Thank you

HG problems are many times more common. A visual inspection of heads with straight edge and feeler gauge can be done to detect head warp. If you have obvious signs of HG, like coolant in oil, white smoke, external leaks; then HG is certainly a place to start. There is a block pressure test a shop can do, you may be able to rent the tools. A block pressure test is not the same as the coolant test you see posted here often. To do the block test you would already need to have the heads off, so once you get them off you'll be at a decision point for that. See Chevrolet Block Pressure Testing - YouTube

I have had my HG replaced tho weeks ago and already my coolant is running low. Oil is clean and no new spots on driveway where My 98 D1 is parked. My father in law says HDs have a breaking period and not to be alarmed. Should i go back to the shop or just add more coolant and wait? Thanks.

Sorry that had some typos. HG replace two weeks ago. Do HGs have a breaking in period?

Not normally as for coolant leak or coolant "consumption" - what does shop have to say? It is true that they may not have bled all the air out of the system and level dropped. You may wish to bring coolant back to the normal reference level, and when driving the truck be alert for sounds like bubbles moving thru pipes under the dash (exhaust gas in coolant), any white smoke after warmed up out the tail pipe, and check coolant level at every cold start for a week. Keep eagle eye on the temp gauge, should not go above midpoint. Ultra Gauge or scanner allows you to obsess more about this in digital form.

Have you seen signs that your engine is burning coolant? I.E. white smoke that smells sweet like coolant?

I am going to guess it wasnt bled long enough and there was air in the system that is finding it's way out.

X2.

Add coolant and wait.