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Author Topic:   305 and 350 harmonic balancers
Dirt Full Roller

Total posts: 42
posted June 14, 2002 09:07 PM
i would like to know if there is a difference in 305 and 350 harmonic balancers. another question is how can i tell if it,s a 3.48 or a 3.75 stroke on my crank, it,s already in the engine.
thanks to everyone.

Dirt Forum Racer

Total posts: 87
posted June 15, 2002 02:27 AM
Both 305's and 350's are internally balanced so the purpose they basically serve is for a vibration dampener. In pickups and cars through the 70's and early 80's most of the dampeners had the same OD but most of the 305 dampeners were "hollow" towards the inside as opposed to "solid" towards the inside as on the 350's. Sometimes the dampener that was used depended on the application, such as passenger car or say a 3/4 ton pickup with a standard transmission. Some of the standard transmission models used a larger diameter and heavier dampener. My personal preference has always been the "solid" balancer over the "hollow" one. Either one will work on either engine, if that's what you are wondering.

Both the 305 and 350 come with identical size and stroke crankshafts. There are a few ways you can tell if someone has "stroked" that engine with a 3.75 stroke crankshaft. You can drop the oilpan and see if the block has been clearanced for the rods, measure the stroke of the piston from the bottom end of the engine, or pull a head and measure the stroke. If the engine appears to have never been gone into before, chances are the crank is still a 3.48. Just a few suggestions. Hope that helps you out!

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