I think it is a Grumman S2F Tracker. The wings, engine nacalles and tail are similar to the B-26, but the short stubby nose is clearly a Tracker. I used to see these all the time over Long Island Sound in the 1960s. They had a very distinctive sound.
http://en.wikipedia.org/wiki/S-2_Tracker
http://en.wikipedia.org/wiki/C-1_Trader