Could your model be 775 or 774, NO 778 model by Savage or Stevens
It has value as a shooter only - not a collector piece. $100-$200.
what the market will bear , left handed model worth more to a left hand er
$200
Marlin started producing the 778 in 1979, production ended in 1984
This is actually a Marlin 120 with a cheaper grade stock. In good condition I would take less than $200.00 for a sturdy and reliable weapon. It has been mechanically compared to the Winchester Model 12.
I am not 100 % sure, but the research I have done indicates that they were produced from 1978-1984, with 1984 being the last year of production. The Marlin Model 120 is the continuation of the Glenfield 778 with some parts being interchangable.
The factors of 778 are: 1, 2, 389, 778.
It is: 778 = DCCLXXVIII
you can find them here... http://www.e-gunparts.com/productschem.asp?chrMasterModel=082Zz778
In good working condition $150 to $200
778 in Roman numerals is DCCLXXVIII
778 kg = 122.5 stone