Boxster Can't Hand-Turn New Water Pump Installed

[JNC]

My 1999 Boxster (90K miles) started leaking massive amounts of engine coolant. I removed the old water pump - WP (had plastic impellers and was original since metal gasket had to be cut) which had a failed shaft bearing determined by excessive shaft play once removed.

I ordered an Ebay replacement water pump (Parts Master - China) that came with metal impellers. The replacement water pump fit up very well to the bolt holes and block and seemed identical to the old pump (except difference of impellers stated above). However after installing the new WP twice without the belt installed, the new metal impellers were striking the engine block, thus not allowing hand-turning of the WP, from one impeller to the next. I inspected the old plastic WP impellers and noticed that they had some wear mainly across the top of the impellers, but also some on the ends, although none were broken or mangled, only smooth wear. I also noticed some some smooth black plastic marks across approximately one/half of the round opening on the engine block where the old plastic impellers apparently wore some onto the block over time or maybe from WP bearing failure.

After the new WP was removed after twice installing, I noticed scuff marks on the ends of several of the metal impellers from my attempting to hand-turn the installed new WP. I also noticed scuff marks on the engine block from the attempted hand-turns where the 2 flow seal 'posts' are located on the block.

Question: Do you think that a slight filing the ends of the new metal impellers, until I can hand turn the water pump installed, without any restrictions, will correct this problem? I don't want to deposit metal filings into the coolant system, causing engine failure as I have read about here.

Also, given the time I've spent resolving this, I've forgot where the 2 long WP bolts (out of the 7 total) go back...I think they go into the holes where the WP bolt holes has ferule extending out of 2 of the WP holes?