Will an LA-360 bolt in where a LA-340 was?

The 340's wer only made for 6 years and were used in only performance applications. The 360's were made for 18 years and were used in most car models and lots of trucks.
LA 360's were made from 1971 up to 1992 (22 years). Then the magnums went from '93 to '03. 33 years total