Hello and welcome to the forum!
I'm not sure what you mean by "guy I got it from sent me a pic of splat on bottom of motor with the numbers 342145 "
Not sure what to make of this number, 342145!?
Actually, a 350 or 327 will pretty much look the same from the outside, they are made from the same block casting and both have the same bore size, 4.001", this difference is the stroke length, 327 has a 3.25" stroke, 350 has a 3.48" stroke.
So, the crank is really the only difference.
The number that will tell the most about the engine is the Engine Assembly Code, it is normally hand stamped on a raised pad, that is located on the passenger front of the block, just below where the head bolts on.
A Engine Assembly Code will look like, V0112CLJ.
This area is normally just behind the alternator and usually gets caked up with paint, grease and dirt.
It may take some cleaning with a rag and some solvent and possibly a wire brush to clean the pad well enough to read the numbers accurately.
If you can find this number, please post it in this thread and we'll try to figure what your engine is.
