Buying a long block 3.9L, what’s the difference between the manual and automatic?
#1
#2
Usually the crankshaft. The manual will have a hole for the pilot shaft. Back in the 60's and 70's, they all had the spot for the plot shaft but now a days, so few automatics are bought by dealers, it's a lot of extra machining to do a manual crank shaft.
#4
Keep in mind I raced in the 70's and ran a salvage yard in the 80's. I can't think of any reason other than that but I've been out of both for decades so I may be wrong. A long time ago, it USED to be a manual transmission engine had a place for the pilot bearing for the pilot shaft. You could use a manual engine on anything but an automatic engine ONLY with an automatic.
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MBrownfield (08-09-2019)
#5
#6
Things likely changed over the years..... On the GM v-8s, ALL of the crankshafts were drilled for pilot bushing/bearings, so it simply didn't matter which one you got. (which actually makes more sense to me...... only need to have one part number....)
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MBrownfield (08-10-2019)
#7
When crate engines first started coming out, they were all drilled. On the production line, it was an extra step to machine the pilot hole. Maybe 50 cents. Multiply that by 250,000, you're talking $125,000 extra cost. It's like the Pinto of the early 70's missing a $1 rubber part that let them explode when rear ended.