Swapping my 1979 GMC straight 6 inline 250 for a 350

[barelhos71]

We are contemplating swapping our inline 6 - 250 for a 350 V8. As im understanding the motor should bolt right in - but what about the bell housing? Does the Tranny need to be changed out? Its a 3 speed manual.

 

[Turbo4whl]

The trans will work fine with the 350. If the 350 was bolted to an automatic, you need the pilot bushing installed in the back of the crank shaft. And of course a flywheel for the 350.

 

[Ricko1966]

@barelhos71 have you sourced any parts yet? I have never seen a small block Chevy that was not drilled for a pilot bearing,but check when you buy,just to be sure. It has happened to me with an Olds big block before. I have a 350 powered 84 c10 parts truck. I'm about an hour from you I think. Anyways if you have trouble finding anything let me know. Things that come to mind,frame mounts,clam shells,accessory brackets ,exhaust manifolds,cables,brackets.

 

[barelhos71]

@Ricko1966 What do you mean "Sourced any parts yet?" If you mean located any (ie: parts truck) No we have not. We are looking for someone to potentially rebuild the current motor in it - or find someone that can drop the 350 in. The two guys (shops) I was talking to both implied I'd need to change out out the Bell housing, potentially the tranny, but remembered from years ago a friend saying it should just align and bolt right in.

 

[squaredeal91]

Chevy had same bell housing for straight six 4.3 v6 all small block and big blocks same housing. Biggest Difference will be engine mounts. Super easy to find those and anything els you will need.

 

[Ricko1966]

@Ricko1966 What do you mean "Sourced any parts yet?" If you mean located any (ie: parts truck) No we have not. We are looking for someone to potentially rebuild the current motor in it - or find someone that can drop the 350 in. The two guys (shops) I was talking to both implied I'd need to change out out the Bell housing, potentially the tranny, but remembered from years ago a friend saying it should just align and bolt right in.

Exactly what I meant. Squaredeal is giving you the correct info. No need to change bellhousung.

 

[squaredeal91]

Sorry Diesel, I forgot to add you to the list lol

 

[barelhos71]

Any suggestions on how I could locate a used 350? @Ricko1966 any suggestions on someone in the area that could drop the new motor in?

 

[Ricko1966]

If you aren't doing the work yourself. I'd suggest you have your engine rebuilt,buy a rebuilt,or get on the internet and find another 250 6 in good used condition. A 350 swap through a shop will nickle and dime you to death.

 

[barelhos71]

@Ricko1966 Thank you for all of your time and input. If we run into a need from a source vehicle - I'll reach out.