I'm happy for you that you got a 231 - it is a sweet engine. I have the same one in my '69 Jeepster Commando.
OK, just want to throw in the ol' adage about remanufactured carbs - they're mostly junk.
They pay very low wages to people to pull them apart, throw 'em in a vat, and then start assembling them from a generic parts bin. if it fits, it goes on...you get the picture.
Unless you got it from a reputable re-manufacturer, like "carburetorsandmore" that tests all carbs on a running engine, you are throwing the dice on whether or not the thing will work right. Unless you know the parts by heart, there's a good chance that the jets, needles and accelerator pump are not the correct ones.
As far as what you're experiencing - did you set the timing 13 BTDC with the vacuum disconnected from the carb? (sorry, don't mean to insult - just checking the bases) If not, reset it with the vacuum disconnected. Somewhere around 79-80, Buick changed the specs from 12 BTDC to 15 BTDC. Don't know if that makes a difference for getting it started and running, but I'll throw those specs at you anyway - you can try it out.
The really important thing is TOTAL advance (initial plus spring weights plus vacuum)
At 2500 rpm, your total advance should not exceed 35 degrees. 32 is what worked best for me (I have a dualjet 210).
What type of ignition do you have? is it HEI?
If it is HEI, please read Rich Motts EXPERT diagnosis of vacuum advance and timing issues with the HEI on a Buick 225. http://www.americanjeepsterclub.org/sw/hei-2.html
Bottom line is that the vacuum from a 2GV is WAYYYYY to strong for the sensitive springs in the vacuum diaphragm on the HEI, and it puts in about 45 degrees total advance...bad juju.
If it is the stock HEI, you WILL NEED TO get an adjustable vacuum diaphragm (about $20) and adjust it to the LEAST sensitivity - read Richard Motts' explanation, how-to and write-up (handle is Rrich on the above forum - do a search for 225 HEI and you will find all of them, and you'll be smarter by the time you finish reading).
The point is, even though you have a 231, you have an HEI distributor... 225's that swap in an HEI from a later-model Buick 231 have had MAJOR problems with vacuum advance, because the 2GV carbs suck so much (no pun intended)
Also, there is a problem with the 2GV carbs with vacuum leaks next to the EGR ports underneath. If you used the FELPRO 6000 gasket, you will probably have an internal vacuum leak. (you can see the very thin gasket portion between teh main holes and the egr port.
There are other gaskets that cover up the egr ports underneath - the best one I have seen is the thick carb gasket from partsdude4x4 (a Jeepster parts site) Here's a link: http://stores.homestead.com/Partsdud...Categories.bok
(I am not affiliated)
I really think, now that I put all that down, that you have way too much vacuum advance. Hope that helps