how to determine which motor

[greg ammer]

1982 38sl, previous owner stated updated V-8 maybe a 1986. Numbers on the valve covers

[deanyel]

You need the first 6 digits of the engine number, which should start with either 116 or 117, on the block somewhere, not sure exactly where.

[ScottinSoCal]

On the back of the engine, between the engine and the firewall. The only way to read it is with a mirror.

[Rally nerd]

the # you are looking for is on the drivers side behind the cyl. head on the block near the bell -housing seam it will be a1169xx 12 xxxxxx number for 3.8&4,2 cars and a117 9xx 12 xxxxxx for 5.0, 5.6 cars.