Hi Michael,    The sway bar you have pictured was first used on the 37 suburban.   By 1939 it was used on all single unit half tons.  (IE: not pickups or stake beds.)  It will not fit 1937 - 40 standard (straight axle) passenger cars as they had a 2" wider spring bolt location than 1926 - 54 trucks so you can't swipe a truck sway bar and bolt it on your passenger car.   I don't recall if the Master Deluxe cars had a sway bar on the double A-arms or not.   I have a 1937 Limousine that uses 3/4 ton axles and has adapters on the front axle.   (I just got a new computer so I can access the new forum but it does not do photos.)      

Thanks for the response. According seller, this was removed from a 39 master deluxe passenger car. I suspected I would have an issue after the fact knowing the 39 master deluxe had ifs with coils. I was told by a friend that this could be installed on my 38 but I couldn’t see it then but was optimistic. 

Did you install it yet Mike?  Do you need me to send you some pictures?

    Hi Mike,    The 39 master deluxe does have a Stabilizer Shaft (Group 7.241, part #599394) that fits the double A arm front suspension of a 39.  It will NOT fit the DuBonnet Knees of a 38.   The Master 85 straight axle, model JB has a Stabilizer Shaft (Group 7.241, part #599739)  that should fit your 38 Standard model HB.   I don't know what it looks like.  Measure it and see if it fits??          

This picture is from the 1939 Chevrolet Engineering Features book