Years	Decal	Shell	Mask	Stripes L to R	Stripe Width	Mini
?-1951-1956-?	none	white	none	orange	1/2"
?-late 50's-?	none	white	gray	orange	1/2"
1964-1966	orange, thin, block "T"	white	gray	orange	1/2"
1965 (special) ^	black cross atop orange, thin, block "T"	white	gray	orange	1/2"
1967-1976	tall, narrow, rounded "T"	white	gray	orange	1/2"
1973 (special)*	tall, narrow, rounded "T"	white	gray	orange/ white / orange	1/2"- 1/2"- 1/2"
1977-1982	short, thick, rounded "T"	white	gray	orange	1"
1983-present	short, thick, rounded "T"	white	white	orange	1"	RR, S, T

 Notes :
^ - This version was worn in the later part of the 1965 season to honor the lives of 3 Tennessee coaches killed in a train wreck mid-season.
* - This helmet was worn the final 3 regular season games of the 1973 season.

Credits:
Thanks to Oscar C. for finding some of the photos for me.

Tennessee around 1956	Tennessee 1964	Tennessee 1965 special	Tennessee 1973 (1)
Tennessee 1973 (2)	Tennessee 1975	Tennessee 1980	Tennessee 2000