You might be able to build a stock engine for around $6500 up here. I built a stock 340 last year on a budget. I reused the pistons, rods and crank and had the block cleaned, honed, etc. and did the assembly, painting and run in. The cost for having the block and rods rebuilt was $1000 + $1400 for the heads (which was a deal). Aluminum heads are $2k and up. Add in an intake, carb, decent headers, water pump, alternator, gaskets, cam, timing chain, rings, etc. and that is another $3500 plus all the parts I missed. That is $5900 plus a good core. Add in new pistons, an overbore and you are well over $6k. You could save a few bucks if you can find a good used intake, carb or manifolds/headers. Once in awhile low mileage small blocks come up for sale if you are patient.
I don't know if you would save any money finding a low mileage 5.7 hemi. The money will go on headers and conversion parts.
I have imported and exported engines before. I doubt you can bring anything in from the US for under $700 these days. I used Fedex Freight. Exchange is 1.41 plus brokerage fees, duty and GST.