Some GMCs have a damper that is an interference fit on the crankshaft. That means no bolts hold it on to the crankshaft. Others, like the later 270 and 302 have a big bolt that sandwiches the damper on the crankshaft. Either way a puller should be used to avoid damage. There are about 10 bolts that hold the timing cover on from the outside, and 2 bolts which hold the timing cover on from the inside. Perhaps you can get a harmonic balancer and waterpump for a 55-59 GMC 270. The later 270 used a smaller belt.
The 270 engine you have is a legendary hot rodding engine. Back in the early 50s it was the engine of choice for hot rodding. Its large displacement, overhead valves, and relatively light weight made the 270 a fierce engine. There were several performance parts made for that engine. There are also several venders who still sell those performance parts. Heres a quick list:
Patrick's antique cars
Langdon's stovebolt engine company
Larrowe and sons
Clifford 6=8 performance
All the venders above can be found on the links page of this site.
You will have to relocate the radiator forward, the gmc engine is longer than that 216.
