727 auto to LA small block issues

This is off topic as far as a-bodies are concerned? I own a 1982 d-150 rear wheel drive with an automatic 727 nonlock up tranny. The truck had a wore out 360 . I had a 1985 318 block rebuilt and used the stock flex plate that came with the 318 . I went to a local transmission/parts supply shop and bought a non lock up 318 torque converter for a 727. At first there was an issue with the torque converter not rotating after tyranny and engine was bolted up? Found out in the center of the crankshaft flange there was a pilot bushing sticking out about 5/16 to 3/8 and causing resistance against the converter. So I pull engine back out and got rid of the bushing. Bolted engine back up now the converter rotates but have to put a little pressure behind it to rotate it and there's a 5/16 to 3/8 gap between the flex plate at the bolt hole and the torque converter bolt hole blocks? Theres about a 2" to 2-1/2" gap between the edge of the bellhousing back to the teeth of the converter ? Should there be more? Also the guy at the transmission supply place says I might have a newer stock flex plate or newer non lock up converter or vise versa? Even though I clearly stated 1982 automatic 727 nonlock up for D-150 truck with a 318 ? Could the snout on the front of the converter be too long and is there a difference in stock flex plates between 70's and 80's small blocks with automatics? Any help would be appreciated