I also think Derrick Parker scored 4 at tha Hall, against Torquay, but I might have that bit wrong.
Here's the list of Southend players who have scored 4 or more in a first team match:
2023-10-21 Daniel Kanu 4 goals v Solihull Moors, National League
1990-11-06 Brett Angell 4 goals v Aldershot (H), Football Lg Trophy
1985-08-23 Richard Cadette 4 goals v Orient (H), Division 4
1977-09-30 Derrick Parker 4 goals v Torquay Utd (H), Division 4
1976-02-17 Peter Silvester 4 goals v Brighton & Hove Albion (H), Division 3
1970-11-21 Bill Garner 4 goals v Weymouth (H), FA Cup
1970-03-28 Billy Best 4 goals v Peterborough Utd (A), Division 4
1968-12-07 Billy Best 5 goals v Brentwood (H), FA Cup
1968-12-07 Gary Moore 4 goals v Brentwood (H), FA Cup
1964-11-07 Bob Gilfillan 4 goals v Colchester Utd (H), Division 3
1964-04-04 Bob Gilfillan 4 goals v Shrewsbury Town (H), Division 3
1959-04-11 Bud Houghton 4 goals v Mansfield Town (A), Division 3
1955-08-27 Roy Hollis 4 goals v Colchester Utd (A), Division 3 (S)
1935-05-01 Harry Johnson 4 goals v Reading (H), Division 3 (S)
1934-11-24 Harry Johnson 5 goals v Golders Green (H), FA Cup
1932-03-19 Les Clenshaw 4 goals v Mansfield Town (H), Division 3 (S)
1930-03-01 Jimmy Shankly 5 goals v Merthyr Town (H), Division 3 (S)
1930-02-01 Jimmy Shankly 4 goals v Queen`s Park Rangers (A), Division 3 (S)
1927-09-10 Dickie Donoven 4 goals v Crystal Palace (H), Division 3 (S)
1926-12-04 Billy Hick 4 goals v Charlton Athletic (H), Division 3 (S)
1924-12-06 Harry Dobson 4 goals v Brentford (H), Division 3 (S)
1923-02-24 Billy Goodwin 4 goals v Millwall (H), Division 3 (S)