I purchased a 383 LT1 a while back and it has been sitting covered in my garage which is heated for a few months now. I finally have money to finish it and I quickly looked through the holes at the rear of the block that get the two large freeze plugs and I thought I saw some rust inside the block

It was dark last night and I didnt have my camera but I am taking pictures the second I go home this evening but how serious can this be?

If its just some surface rust am I ok? Would this just effect the cooling system or am I in for catastrophic failure if I attempt to run the engine and there is some minor rust in there. I need a closer look today but I cant even sit still without know what is going to happen now...

By the way this engine was completely rebuilt with new internals and all block work was done at a local engine/machine shop and at time of purchase everything seemed perfect.

Any help/thoughts would be appreciated

 

That's about as normal as sand in mexico. Blocks will get surface rust in the water jackets. Totally normal.

 

I guess a good flush after initial start up will help clean out any crap in there...