Truck tall block

[paradigm shift]

I picked up a truck tall deck block this summer. When I had it mag checked for cracks right after I picked it up I noticed it had MARINE cast in the bell housing by the part number. Did not think much about it until this weekend. Went to do some busy work to get rid of flash in the lifter valley and do some clearancing for the stroker crank and the block is much harder then my last one.
Could the MARINE mean it is a higher nickel block? It is noticably harder when cutting with a carbide rotary tool bit.

[TIMINATOR]

Yup, more nickle in it. If youre gonna stroke it to 496, block rock the bottoms up about an inch and a half. Its easier to do before you grind holes in the jackets. Also you may not strike water now, but it will be thin enough to cause grief later. TIMINATOR

[paradigm shift]

This is the second block I have clearanced and I really did not think it takes that much to cause problems but I am certainly not the expert. I have a 4.5 stroke crank under the bench I am considering using and even though I have had no trouble in the past I will look at hard block filling the bottom. What are your thoughts on oil cooling with a partial fill like suggested?
Since the block was used I planned on line boring and I managed to pick up some billet caps with ARP studs so I want to get all the work done before machining.
Thanks

[TIMINATOR]

You are correct sir, when you fill a block you are removimg an area of cooling for the oil. It will probably be ok, but you may need to keep an eye on it. You can always add a cooler later. Core shift determines when you will likely strike water, most 4.5 stroke BBC blocks will hit water regardless. Adding billett caps is good insurance, but I personally don't worry about it until over 800 HP or so. I have run street/strip cars with 2 bolt mains and studs(running it every weekend and street duty too) for 3+ years at 620 on the motor and 300 NOS. 10.80@124 motor, 10.00 flat 138 squeezed, in a steel 72 Chevelle with STREET TIRES (no traction!), P/S,P/B and mufflers(quiet ones). BUT! in that situation I was only on it for 10 seconds, NOT miles! After 3+ years on teardown, the caps spalled metal to the block because they were moving around. No crank damage, i just pulled it down because I sold it and wanted to make sure it was OK. A line hone, and new bearings and it was good to go. The new owner only wanted the car for its reputation, I don't believe he ever ran it at the track. TIMINATOR