Posted by Ken Dunnington [172.68.34.19] on Saturday, October 21, 2017 at 01:36:03 :
In Reply to: OT: Saw a 58 GMC Napco with V8 today posted by Gary in CO [108.162.221.83] on Friday, October 20, 2017 at 23:52:05 :
I have long wondered why GMC lowered the displacement for '58-'59 on the Poncho V8. I once drove a 2-ton GMC with what I thought was the '58 370 Pontiac V8 mated to a five speed but it turned out to be the under-bored 336. GMC used the Pontiacs as is until '58. I found that strange since the '58 370 was the best of the lot(including the '59 389)
I am familiar with the '55 287, '56 316, '57 347, '58 370, and '59 389. The displacements crept up from 287 by increasing bore for '56, stroke for '57, bore for '58, stroke for '59 from whence the 389 lasted for 10+ years with the 421 thrown in as the top option in early '60s.
I ran the 347 and 370 in my '55 Chieftain. Still have the 370(domed Venolias make for not so practical street use though) and some hard to find main bearings for the early Poncho V8s. Rod and cam bearings stayed the same from '55 on but the'55-'58 all have smaller diameter mains than the '59 on and whew they were pricey back in the '90s. I wonder what my drawer full of early mains is worth now...
Anyway, back to PWs...
Ken
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