water jacket holes are different

I have a non HO block that I'm putting in the rig, but the water jacket holes aren't the same as in my crap HO block (see pictures). The HO unit has the same holes as the other plus some. Will this cause problems with cooling since my HO head will have extra passages that the block doesn't have? Would it be okay to add holes to the block where they should be?

Non HO block


HO block


TIA

You need to epoxy the unused holes shut or your head gasket will leak like a mofo. I did this on a yj not too long ago. Except it had the 4.2 block.

Oh yeah, nice boots!

Terry I think this belongs in mod. tech.

logdog said:

Oh yeah, nice boots!

Click to expand...

Thanks.

Would it be so bad to drill holes in the deck where there should be holes? I can use a die grinder to shape them into the rounded triangles that they need to be. Then deburr it and I should be golden, right?

I don't want to wind up with overheating problems, as I had absolutely none with my previous block.

Buck, how many miles on the odo?

Never mind. I just found a thread that explained that the extra holes were from the casting of the block so the sand from the process could be removed more easily.

I checked my gasket and sure enough, the extra holes arent on it.