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Old 07-16-2013, 01:27 PM
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350 to 305 v6

i have a 67 gmc c25 with a 305 v6. i am about to buy a 71 k20 with a 350. the 350 in the k20 is shot and i want to replace it with the 305 v6 from the c25. can anyone tell me what if any major roadblocks i will encounter? will it drop in without major customization?

it seems there is alot of info on doing the opposite but noone talks about ditching the 350 v8 for the 305 v6.


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Old 07-16-2013, 01:34 PM
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Originally Posted by huntaaar View Post
but noone talks about ditching the 350 v8 for the 305 v6.
Everything you're talking about here is made by GM and all of it was originally fitted to a truck at the factory, so all the parts to do it are sitting in a boneyard somewhere if you can't use what's on the trucks already. I would think that you could just remove the motor mounts from the '67 and bolt 'em into the '71. It might not be exactly that easy, but it certainly shouldn't be difficult.
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Old 07-16-2013, 03:28 PM
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The 305 GMC has a different tranny bolt pattern than a Chevy or BOP. If you want to run a stick you need to use a GMC bellhouse. The AT trannys used an adapter of some sort- it's been a LONG time since I saw one in our 'yard. The rest is basic plumbing of fuel lines and wiring the ignition and starter, all straight forward stuff.

You need to look around at the 6066 GMC Guy for links to forums like 6066 GMC Truck Club Forum.

Last edited by cobalt327; 07-16-2013 at 03:36 PM.
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Old 07-16-2013, 07:30 PM
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dang i cant believe 2 people responded to help me already. this site is awesome! i'll start looking into getting a gmc bellhousing once i figure out exactly which tranny im deallin with (hopefully the muncie 465). this will be my first engine swap im sure i'll have more questions. thanks
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