I'm 5'10" and run 190-200# and I'm totally comfortable in a 150 and I dont put the seat all the way back.
I've flown with 6'2" guys and they just put the seat all the way back. Older bigger guys just complain about getting in and out, but once in have not complained for a 1-2 hour flight. Do need to throw an arm over the back seat if there are two guys with big shoulders. Very old 150's did have a narrower cockpit, I "think" it was around '65 when they widened the cockpit another couple inches, not sure on the date though.
At 6'3" and 230# you'd just have to try it, different body builds seem to fit differently, but you are definitely going to be at the edge of the comfort limit.
Mine is 1060 empty, with a 1600 lb gross. 140lb for full fuel (standard tanks). That leaves about 400lbs for people, so I generally leave mine at 3/4 fuel which saves a little weight. It's not going anywhere fast at gross, but then again it's not going anywhere fast lightly loaded either.
Went to do spins last week in mine and we were about 25# under gross. At 65° F we took off in about 1200' and climbed at 400 FPM to about 6,500' and probably 350 FPM to 8,000'. Worked out just fine, and at 5 gallons per hour fuel burn... pretty hard to complain when it comes time to stop at the fuel pump ;o)
I did do one longer X/C under the hood in mine and we took off at gross in about 85°F (3000' pressure) one late afternoon and it was interesting...a good 3000' ground roll and accelerating in ground effect and a slowwwww steady climb after that. I wouldn't want to do that all the time, but we had the runway for it and dropping temps as it was the start of evening.