(first posted 4/8/2017) Unless you’re a certified bus fan (and a certified old guy), it’s unlikely you’ll recognize this coach. Motor Coach Industries (MCI) built only 100 of them for Greyhound between 1969 and 1970, and they spent most of their time on roads in Canada and on the two US coasts. When introduced, it was probably the most unique intercity bus in service. It’s an MCI MC-6 Supercrusier.
First some history – by the mid-1960’s, Greyhound’s General Motors PD 4501 “Scenicrusiers” were getting tired – they had been in front-line service for a good 10 years and needed to be replaced. You may remember that Greyhound purchased MCI in 1959 to serve as its sole source provider, largely based on its disappointment with the 4501, which had initial powertrain reliability problems and later developed cracked frames.
MCI already had their successful MC-5 as a replacement for older GM 4104 and 4106 models.
But the company needed a larger, high floor model also, so to meet this requirement, MCI developed two new buses jointly – the MC-6 and MC-7. The MC-6 was certainly the more unique of the two. How so?
Size: The MC-6 was the first 102 inch wide 40 foot long intercity coach. At the time, Canada and several US states on both coasts had increased their interstate highway maximum vehicle width dimensions from 96 to 102 inches. Greyhound had assumed, incorrectly, that other states would follow suit and adopt these wider limits also. But many states kept their 96 inch rule until the Federal government enacted the Surface Transportation Highway Act in 1982 which standardized the 102 inch width on the entire national highway network. As such, these buses were confined to routes in Canada and along the two US coasts. Initially, the MC-6s operated only on the East Coast, but later were all sent to work on the West Coast.
At least the first two prototypes had their non-driven tag-axle wheels covered by bodywork, like this one seen in San Francisco, but the production versions had exposed wheels. And one of these two prototypes used a Mercedes 8 cylinder diesel, so it appears that MCI and Greyhound were in the same quandary as they had been back when they built the Scenicruiser: the lack of a just-right sized DD engine for this bigger bus.
Power: The MC-6 was one of few coaches to use the GM/DD 12V-71 engine, a 14 liter, 852 cu in V-12 monster than twisted out over 400 hp and 1200 ft lbs of torque (other versions would go up to 600 hp). With its unique two stroke exhaust note, this engine was nicknamed the “Buzzin’ Dozen” and was paired with a Spicer or Fuller manual transmission. It gave these buses superb performance, albeit with a penalty in fuel consumption. The eighty-five MC-6’s in the US (fifteen remained in Canada) were subsequently re-engined with the 8V-71T and Allison automatics in 1977 when they were sent to the West Coast. The US fleet was retired in 1980, and sold off to other operators.
The Canadian MC-6s retained their DD 12V-71 engines and manual transmission.
Multi-stepped Seating Area and Roof: Most models in the late ‘60‘s-early 70’s had stepped seating areas and notched roofs; the GM Buffalo, Eagle Model 05, etc. The MC-6 had two stepped areas (not including the entrance); three steps up to the first seating area behind the driver, then one additional step up to more elevated seating from the middle to the rear of the bus. In turn, the roof had two notches instead of one. This made it 12 ft tall at its highest point, so it was not only the widest but also the tallest intercity bus then in operation.
The more mainstream MCI MC-7 (96 in wide, 40 ft length) developed in conjunction with the MC-6, achieved much greater success, with over 2500 being built, and soon became the mainstay of the Greyhound fleet.
But the MC-6 was the largest (non-articulated) and most powerful intercity bus on the road until the introduction of the MCI 102A3 and Eagle Model 15 with the DD 8V-92TA engine in 1985.
Truly ahead of its time; six inches too much so, actually.