Peter J. Malanchuk

Hello all, I am a member of the AHTS-Coastal Carolinas Chapter since last year, when our specific chapter was first formed. ATHS stands for American Truck Historical Society. I'm 72- 1/2 years old and have liked trucks, locomotives, things diesel powered, as my dad got me interested in all things mechanical from an early age maybe when I was 6 years old. My Dad also used to bring me to the LIRR station, Mineola, NY, to see first generation diesel locomotives. Anyway, on Mack trucks, I recall vividly, as an early teenager, a specific Mack diesel tractor which pulled 9,200-gallon size aluminum Heil, Trailmobile or Freuhauf tank trailers for Gulf Oil Co. There were two tractors I saw in mid 1960's. These two trucks would travel south on Henry Street, in the village of Hempstead, NY, and stop at the traffic light at Peninsula Blvd., and Henry Street. One was a dark blue and orange tandem tractor, with orange cab, fenders, blue six cast spoke wheels, long hood, axle set forward, with big rectangular radiator with what sounded like a Cummins NH230 in it. The other, which I'm very curious about, was a nearly identical Mack B-73 tractor, but had a very quiet in-line 6-cylinder diesel engine in it. It certainly didn't sound like a Cummins NH220 nor a Cummins NH230. It may have been an experimental engine and I was thinking it may've been powered by a 6 cylinder-in-line, Mercedes-Benz model L334C diesel engine, which M-B offered for export, introduced in 1962, with the power of the engine increased to 200 hp. I was wondering if anyone has info on these two Mack B-73 trucks or knows if the Gulf Oil Co., has archives which may have info on these Mack B-73 tractors. There is a YouTube video from 8 May 2017, the video is owned by a "Zukes Rubicon", which shows a very similar Mack tractor with Gulf Oil which I'm referring to, but it has a Cummins diesel engine in it, it's a 1962 Mack model B-73 restored, it sounds like a Cummins NH230 idling under that hood; ref. video: www.youtube.com/watch?v=gNsVULcMfBA. Thank you in advance for your help. With kindest regards, - Peter J. Malanchuk

This is a Mack model B-71 which came out in 1953, when all of the new B series came out. This model may have the Cummins NH-220. The early Cummins 673 CID six had a 4-7/8 in bore by 6 in stroke, the successor the 743 CID six had a 5-1/8 in bore and 6 in stroke and the successor to the 743 CID six was the Cummins NHC which were 5-1/2 in bore by 6 in stroke with 855 CID. Foe a short period Cummins made the Super 250 which displaced 927 CID, same 5-1/2 bore but deeper stroke/sleeve.