magnum heads questions

Ok guys

I have a fellow mopar junkie who runs a salvage yard in my town. He has a dodge pickup with a magnum 318. Its got a bad bottom end knock, miles a tick over 100k. I was thinking ofbuying the heads off him for my 74 model 318 mild buildup. I have heard these are crack prone. I can get them with all the hardware, rocker arms, and valve covers. I know what other parts i will also have to get to make em work on my non magnum shortblock.

Now for the question. He wants $100 per head, im thinking i can clean em up do a valve job, put heavier duty springs in them, maybe some new guides if needed, and head on down the road.

Or i can save my $$$s up and buy a set of ready machined EQ magnums for about $300 and change per head, and still have to get valves, springs, retainers, valve covers, rocker arms and all the hardware etc.

He told me to get em pressure checked, and if they dont leak good to go, if they do leak he would take em back, and give me my $200 back.

Also are the magnum headbolts a stretch type bolt requiring replacement every time you pull a head, or can these be reused? If they cant i will just buy a set of ARPs.

Any suggestions? Like most folks here im a working stiff on a working mans budget.

Thanks
Matt