Another converter thread

Do not buy anything less then a 3500 loose. If it were me I would buy a 4500 tight. factory 340 cars came with a 3000+ same converter as a Hemi or any HP Big block. 340 cars flash stalled at 2800-3200. Hemis and HP big blocks with the same converter 3000-3400
Sir could you please explaine what the terms loose/tight and flash mean I think I have an idea but just want to make sure....thanks