That'd make you go back to bracket racing with a small block pump gas motor. 

I took a set of 2V D1 heads and put 2.19/1.71 valves in them.  Did some porting, smoothing, etc.  At about .450 lift on the flow bench, the air quit making the short turn with a BANG and flow dropped like 30 cfm.  Still ended up in the 250 range at .550 on intake but it was weird.  D3~D5 cast "4V" heads all came with open chambers and  the 2V 2.04/1.66 valve sizes.  Most of those heads are D5 castings AFAIK.  If that short turn is close to the valve, IMHO as a total amateur porter I think you'd possibly aggravate an already iffy flow condition by increasing the valve size. The tongues raise the floor and give the air a better shot at the valve which would make the port work better for the larger valve area. 

I'd also go with "replace".  Trying to turn those solid/thin rotors (or really, even OEM kind of rotors) on a regular bench lathe isn't a good idea IMHO because you have cutting pressure only on one side of the disk.  A normal disk lathe has cutters working both sides at the same time to offset the cutting pressure.

BTW - OEM deck heights and chamber volumes are darn near random numbers.
I have observed unmodified engines that were way, way off.

Having measured and paid for machining of several "as Ford built" 351C and 302 blocks and iron cylinder heads from the 60s - yep.  Published specs are "nominal" at best. 

351Cs - "four-barrel upgrades over the two-barrel engines were stainless-steel head gaskets, higher valve lift (an increase of 0.025-inch intake/exhaust), a different combustion chamber with quench area yielding an 11.0:1 compression ratio, and dual exhaust. "  11:1?  Um, not so much.    Measured one of those "11:1" motors before updating - try 9.99:1.  But lets not let data get in the way of a good argument.   

I like the idea of a run stand but is it really a good idea on a new engine when you can't load it to seat rings?

I just fired my 351C after a total "roadkill" cleanup of the cylinders with a brake hone, hose water and CRC Power Lube followed with a 320 grit ball hone with 10w-30.  Moly ring set, seated fair enough on start.  No issues with the cylinders, after maybe 5+ minutes total run time, 150 PSI on #1.  That's with a huge 248/254 solid roller at 108.  Not my usual practice but I'm just trying to get by until I can get the 427W up and going LOL.

Same - 9" with spool, all the above.  Tires chip on corners on the street, "scrunch" around at the track on what are usually not wonderfully paved surfaces at most tracks. Drive on wet road at your own risk.  If it's a street/strip type car, much better off with a DL as it will unlock for corners and be a bit more forgiving. Not much, but some. Both require respect and restraint on the street.  The two main things with a DL is on the strip, make sure you have enough room to pull straight forward after a burnout to be sure the DL is locked.  And on the street, never "punch it" going around a corner.  It will not do a cute tail wag - the DL will lock and send the nose heading in whatever direction it happens to be pointing.  Don't ask me how I know these things 

I really need to build one of those engine run in stands - super handy thing.

I'm running on this-season-#3 year - VP110.  I keep it in the drum, tightly sealed, in the shed.  When the season is over, I leave maybe a couple of gallons in the cell for winter tinkering, any extra goes back in the drum. It's about time for a new drum, I hesitate to price it.  I intend to try and run methanol mid season. That for sure has to be tightly sealed in storage.  I also add Klotz top lube to the drum when I buy the fuel that way.