compression ratio-1995 5.7 truck engine

I bought a 1989 Astro van mainly because it already has a ruuning crate 350  in it.The engine came from a 1995 Chevy truck which the engine was replaced  with this crate engine at 3,000 miles and was found in a junkyard after the truck was involved in a rear end crash.The engine I.D. numbers are:10243880 and Mortec said it is a 1996 Chevy 350 Vortec block with a roller cam and a 4 bolt main.The guy I bought the van from told me he did have the pan off of it and confirmed it is a 4 bolt main.Here is what I think happened.The engine was replaced with a short block and the heads and TBI and intake was used from the old 1995 350.(yeppers-I found out the Vortec's did not have TBI's and certainly didn't have them in 1996.)

So here is the question.What was the compression ratio for 1995 350(5.7) truck engines??.And what was the C.C. size of the heads used in the same truck engines??.(I.E.: 76cc or 64cc,etc.)

Briefly,I bought the 1989 Astro 350'ed van to use it as a donor for my 1985 high top Astro which will be used as a tow van for my fleamarket business towing a small vendor trailer.I will transfere the engine,tranny(it is 1991 700R4 from a V8 truck),wiring harness,and computer into the carb'ed 1985 Astro.I don't want to swap a low output 350 into the 1985 Astro.Doesn't make much sense to swap a 350 that has about the same torque and hp as the 4.3 that is already in there.I was going to do some mods to the engine anyways for some smiles on my face when I am driving it without the trailer behind.So I am trying to gain more info before I put a game plan together of what parts to buy.

Sorry about the long post,

Thanks for your help in advance,

Gary


This is the 1989 donor van where the 350 V8 is coming from:

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And a Picture of the engine:]

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This is a picture of the 1985 Astro van that is getting the 350 V8 swaped into it:
 
 
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The nickname of this van is "Ole Yellar".The bell and decal's are long gone and it is old picture when I bought it.Going to add no window slider,and a no window rear doors,repaint a little deeper color yellow.