Found a BBGMC v6 401 in TN
 

Guys, I was trying to get this deal in TN to go in my 1957 Western Flyer 4x4 Bus/RV to replace the dead 351 that it came with from the factory. However, after many considerations i thought the 401 was going to be an overkill. Here is the link in case someone is interested: https://www.facebook.com/marketplace...0455533730260/

Instead, I bought a 1969 C30 in TN with a 305. It will be bored to 351 and i will be using the pistons, heads and carb from my 351. My 351 throw not one, not two but THREE RODS and I hope the pistons are still good. This way my bus will continue having a 351 motor as it came for the factory with it's 6 speed allison transmission.

Re: Found a BBGMC v6 401 in TN
 

The GMC V6 engines were introduced in 1960 so that would be impossible the 1957 Western Flyer came with one from the factory. As far as boring a 305 block to accept the 351 pistons that also seem unlikely, it would by far exceed a maximum overbore of .060. The 351 pistons are considerably larger over the 305 piston bore. 4 1/4 vs 4.56.

Re: Found a BBGMC v6 401 in TN
 

You'd be much better off with that 401 than a 305 in something as heavy as a bus. It would definitely not be "overkill" as you say. That 401 probably has way fewer miles than that 305.

Re: Found a BBGMC v6 401 in TN
 

I barely know my butt from my elbow but I can definitely say that boring your 305 to 351 is a gamble. A shop might not even do it for you due to safety.

But...if you grab that 401....you'll be sent to the hospital to have that grin removed from your face. It's not overkill at all, these engines are made to lope along forever at low RPM. You'd just be making it happy and in return it'll make you happy too. Go for it! :upyes:

edit: :welcome: to the forum!

Re: Found a BBGMC v6 401 in TN
 

LOL., that is a funny saying. I am new to all this GMC V-6 Big Blocks but according to Wiki, the only difference between a 305 and a 351 is the bigger bore, improved heads and larger carb. Block is the same as is everything else.

I will try to post some pics of the engine bay but everything is really tight fit in there so I am sure I am sure if came from the factory (in 1957) that way with that engine. I don't know if Western Flyer had access to those engines before GMC released them in their lined but if it was a later down the road add, whoever did that conversion did an outstanding job.

Re: Found a BBGMC v6 401 in TN
 

I'm sure BBv6 will be in to correct us, but I think they had different water jackets (is that a thing?) too to account for the added heat/pressure. IIRC, and I may not, they weren't just 305s with bigger pistons + heads.

Re: Found a BBGMC v6 401 in TN
 

Upload of a 89kb picture failed. Let me try again.

Re: Found a BBGMC v6 401 in TN
 

Pics... fingers crossed.

Re: Found a BBGMC v6 401 in TN
 

The engine serial number in your last photo bears no resemblance to a V6 serial number. The very earliest V6s were installed in a few model year 1959 trucks for testing purposes.

You can find your engine's serial number stamped into the top of the block between the cylinder head and that big alternator of yours. You can see what to look for here: http://www.6066gmcguy.com/EngineData.html

Re: Found a BBGMC v6 401 in TN
 

Looking at the pics of the engine it appears that you have a 351 Magnum V6 which was first introduced in 1966, I would say it's either a 66 or 67 year engine. If you replace it with a 401M hang on to the Magnum heads and manifolds both exhaust and intake.