Steve,
Rather than cut a 998 or 1098 crank's webs down to fit in an 850 block (which weakens the crank) it is preferable to machine the block to clear a stock crank.
Back in the 60s I modified many 850 blocks to take a new 1098 crank, rods and pistons.

From memory, they need .062" faced off each side of the centre main cap and block, and .085" off inside of the end ones. Use 850/948 thrust washers, 998 ones won't fit the 850 cap.

I used to have a blast driving around in an 850 automatic.  Sure, top speed wasn't great, but I just used it for bombing around town.......winter also.

Starting off in 2nd or 3rd got me going on icy roads quicker than some other cars around ( before winter tyre technology )

Acceleration was not bad really....when shifting manually....was a fun car in the dry.

They are not boat anchors....the humanity !

Yes it is.

I currently have it listed for sale for at $1,000,000 but I am flexible on the price. PM me and we can see what we can workout.

Is this engine still available?

It's like a drag race at every stop light just to keep up with traffic.

Well Bochinam, we have a race. My 850 will do 0-60 in the same day. 0-65 is maybe. That is after boosting my horsepower by 10% by adding twin SUs. It went from 27HP to 30. And who says the 850 is an anchor?

Well, if someone is making donations send them my way.  My 1976 850 is running like a top with a 0-60 time of "maybe".

I've picked up at least 7 850 lumps, never paid a penny for any.  Owners were happy to see them go, still have another in the area to get at some time.  If it was a 68' to 72' 4 sync majic wand the trans would have some value.  B type 3 sync majic wands can donate hubs,forks and shafts for rebuilding more worthy 3 sync boxes.  Also have aquired unwanted 998 +1100 lumps free as well.

As for overboring the 850, I was involved with someone who just wanted to try it and had a set of Hillman Minx pistons (if I remember correctly) that were .100" or more oversize of the 850.  Bore went fine, rod small ends (pinch bolt type) bored +.030" to fit pins, piston tops cut to match deck and distributer drive turned down to clear piston skirts.  Fitted with a 997 cooper head it ran well, but was it worth the effort? 

Piston are one of the problems with an 850. Mostly NOS or new ones fron OZ a little expensive. I looked at having a 998 crank cut down to fit an 850 block then pistons to .100 O/S can be had. Steve (CTR)

Out of curiosity how big an overbore can you do on an 850?

My last load to the recycle was 7 dollars per 100 lbs. As much as I love the little power units I could only offer to unload one if brought to my shop. I do offer them a safe in door storage area. A number of years back I offered to pay in bound shipping for 998 complete power unit cores. I stopped after 5/6 showed up within a month. So far I have not been able to sell on a single part from that exercise. No big deal I was able to give away a running core to someone needing power and having no money. Steve (CTR)

Dan you don't have your email info in your profile.

IM me.

dan 

Scrap metal prices are about $11 per hundred.  Not many folks want an 850...as you are aware of, they are very slow.

I will be doing an engine upgrade on my mini and will have a good running 850 with magic wand avaiable soon.

What woukd be the market price for the lump?

Thanks,