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400sm block questions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CaveBlazin, Jul 30, 2002.

  1. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

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    Ok here's the deal a buddy of mine is gonna sell me his 400 out of a 72 bonneville. What kind of problems will I run into when doing the change from the 350 to the 400 both are 4 bolt mains Im just wondering if I will have problems Ive heard different opinions about the 400 and is there a difference in the size of a pontiac 400 and a chevy 400.If you could let me know before I purchase this engine Im getting a REALLY GOOD!!! deal.......
     
  2. RaisedK5

    RaisedK5 1/2 ton status

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    Well for one the poncho motor has the BOP (Buick-Olds-Pontiac) bellhousing patern, so you would need an adapter plate, or a new transmission to go with that engine, motor mounts are most likely different, and thats just the start of the physical differences, not to mention the legalities, if any of swapping that motor into your blazer, its a lot of work, and not as simple as just pulling one out and sticking the other in.
     
  3. 95 Silverado

    95 Silverado 1/2 ton status

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    first thing, as was said in the other post, if it's in a bonneville it's probably a pontiac 400 and not a small block chevy 400, if you are getting the whole car you will get all the brackets and accessories needed to use with the engine as the chevy brackets and such won't fit, the exhaust will have to be changed, and the transmission will not bolt up to the pontiac bolt pattern.
     
  4. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

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    Yikes!!! But do you think its worth it to do it how hard is it to get bellhousing brackets and adapter plates and such. Maybe I just should look for the ole chevy 400 instead...
     
  5. bigmack

    bigmack 1/2 ton status

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    I think finding a 400 chevy would be your best option. It just sounds like it would be a major PITA to put a pontiac motor in there.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Too much hassle IMO. It will make a cheap swap (motor) into an expensive one. (motor mounts, tranny bolt pattern, length, etc)

    besides, more than likely, building a Chev 400 will be cheaper than a Pontiac 400. Nothing wrong with Pontiac, but in your case, I'd stick with Chev.
     
  7. CaveBlazin

    CaveBlazin 1/2 ton status Premium Member

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    Thanks All,
    Man you gotta love this site!!!!!!
     

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