LA360 compression

ok engine builders. Here is my dilemma. I bought a Mabbco rebuilt 360 short block from a member. Some upgraded stuff like KB high compression flat top pistons, moly rings, 272 muscle cam (272/272 duration 454-454 lift) Cloyes HD timing chain and sprokets. .30 over bore. Got a nice brand new set of Speedmaster aluminum heads with 68cc combustion chambers.
Here's the problem; my engine is at a builders for finishing. Went by there yesterday and he said this engine will be an absolute dog as it sits now. He doubts it will make 8:1 compression. Yes, the pistons are below deck a little, but he says I am losing a lot of quench with them. He suggests new pistons, rods, roller cam and new crank. That's an expensive prospect, considering what I already have in the motor. Also, this guy is a very well known builder with a great reputation and is well known in the racing circuit. His shop is incredible and he rebuilds engines for a living, and has many many great reviews. He does not even want to assemble the rest because he says he knows I will be disappointed.
What to do? Will this motor be a dog like he says? I don't know that I have the scratch to have him tear down this motor and upgrade it to a stroker.
TIA.
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I went back and read all of this in depth. Here's what I would do. With that small of a cam, I would build it AS IS. Give the ignition a good hot curve. Something on the order of "around" 20 degrees initial with 35 or 36 total all in by about 2700 RPM and it will scream for what it is and run on 87 octane ALL DAY LONG and never complain. I think you're overthinking things because of what all the forum heroes and magazine articles say. Build it.