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Thread: 305 vs 350 differences
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10-05-2008 #1
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305 vs 350 differences
having been out of GM loop for 20+yrs.
i know these motors are pretty much identical.
what are the differences?
meaning, what parts don't interchange.
will intake and distributor go from my 305 to a 350?
what difference is dist between my 305 and say a hipo factory 350ish motor?
1982 Grand Prix LJ: 3.8~T-top~buck/con
1986 Grand Prix LE: 5.0~T-top~buck/con~over 35 extra cost options~you could say it's LOADED.
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10-05-2008 #2
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Intake and distributor should swap. Pay attention to the center two bolts on the intake, as some later 86+ (i think) had straight bolt holes as opposed to the earlier angled bolts.
10-05-2008 #3
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Pistons will not swap, head gaskets are different and some big valve heads will not fit on the 305.
thats pretty much it if I remember right (i'm talking pre 86 here as I have no experience with later motors)Have Fun!
André
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10-05-2008 #4
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Crank, flex plate/flywheel, & balancer interchangeable? I know they are both 3.48" stroke, but I was told years ago they are not interchangeable because of the balance. But I don't know why it wouldn't be any different than using a 400 crank in a 350 block.
Scot
86 Monte SS
10-05-2008 #5
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The only differences in the motors that I know of are the pistons because of the bore size, and the heads. They also used a different grind cam, but it is interchangeable between the 305 and the 350. Both are internally balanced, so the balancer and flywheel will interchange. The only time this is different is if it's a one piece rear main seal. I think that changed in '86, but I might be wrong. Either way, pre-'86 parts swap just fine with pre-'86 motors, and '87 and later interchange with eachother as well. Also with the '87 and later heads, they went to center bolt valve covers and changed the angle on the two center bolts on the intake pattern. There might be something I'm missing, but that's most of it.
Allen Ortega
Meanstreets Performance Fabrication
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