High praise from Doug Flutie ... the ex-Bills QB says he loves Josh Allen so much, he could see the signal-caller one day taking the title of best-ever Buffalo quarterback from Jim Kelly.
Flutie dropped the compliments after dining with Joe Montana in Los Angeles earlier this month ... saying he's just that big of a fan of Allen's.
The 59-year-old, though, said the current Bills QB has a bit of a ways to go to catch the former one.
"I love Josh Allen, love everything he did -- he had a tremendous year," Flutie said ... "I'm not going to say he's going to [overtake Kelly], but the potential to do so is there."
Allen just wrapped up his fourth season as the Bills' starter -- going 39-21 in 60 games with 14,114 passing yards. Kelly, meanwhile, went 101-59 in his 160 career games, throwing for 35,467 yards.
As for dinner with Joe Cool -- check out the video, Flutie said it was a surreal experience to eat out with the original G.O.A.T.!