250 IL6 to SBC swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TheSeeker · 08-18-2012, 04:20 PM

Hey all, I recently developed a pretty bad low end knock in my stock 250. I want to pull the motor and swap out to a small block. I am currently starting with a bone stock 6 cyl truck. If anyone has done this swap, can you tell me what I would need to complete it start to finish? Kind of a parts list cheat sheet if you will, (Fuel line changes? Cross member? Can I use the 3 speed manual I have? etc.) I am sure I can complete the project ina few weeks with good buddies and good brews, but dont want to go in unprepared. Thanks in advance for any insight!

p.s. I know a lot of folks like the old 6 banger, I did too, I think it gives the truck character and was cool to see at shows. However, I daily drive this truck, and tracking down parts, pullies, brackets etc to fix it/rebuild it and add air and ps, is a huge pain. Anyone who has owned one of these 6's will tell you the parts supply and price is a huge con to owning one instead of the sbc. :/

PanelDeland · 08-18-2012, 04:50 PM

I'm one who loves the 6 but if I had to replace an engine,I would probably save the money by going to a350 also.The towers and placement are different in the V-8 truck(BB and SB also).The tranny works,IIRC so does the bellhousing and clutch but you will need a flywheel.The bellcrank and mounts for it are different for the V-8 clutch.I'm sure that's not all but someone will probably point out my shortcomings.

68gmsee · 08-18-2012, 08:59 PM

ttt

It's been many years since I converted mine but I remember the drive shaft was different in length also. I used a complete 350 engine and 350 transmission off a 75 Impala.

My advice is to see if you can find an old clunker 68-72 if you can otherwise it's going to take some time to locate what you need. Be sure and check this site's parts for sale section, ebay and even Craigs lists in your state for cities near you.

pritch · 08-18-2012, 09:32 PM

Quote:

Originally Posted by 68gmsee

ttt

It's been many years since I converted mine but I remember the drive shaft was different in length also. I used a complete 350 engine and 350 transmission off a 75 Impala.

If you use the original 3 speed, the drive shaft should work. The transmission shouldn't have to move unless you mount the V-thingy back in the L6 position, which some guys do.

TheSeeker · 08-19-2012, 02:32 AM

OK. Weekend got away from me so I am just gettin back on this now. Thanks for the help guys. Anybody else have any pointers?

08-18-2012, 04:20 PM	#1
TheSeeker Registered User Join Date: Dec 2009 Location: Glendale, AZ Posts: 337	250 IL6 to SBC swap Hey all, I recently developed a pretty bad low end knock in my stock 250. I want to pull the motor and swap out to a small block. I am currently starting with a bone stock 6 cyl truck. If anyone has done this swap, can you tell me what I would need to complete it start to finish? Kind of a parts list cheat sheet if you will, (Fuel line changes? Cross member? Can I use the 3 speed manual I have? etc.) I am sure I can complete the project ina few weeks with good buddies and good brews, but dont want to go in unprepared. Thanks in advance for any insight! p.s. I know a lot of folks like the old 6 banger, I did too, I think it gives the truck character and was cool to see at shows. However, I daily drive this truck, and tracking down parts, pullies, brackets etc to fix it/rebuild it and add air and ps, is a huge pain. Anyone who has owned one of these 6's will tell you the parts supply and price is a huge con to owning one instead of the sbc. :/

08-18-2012, 04:50 PM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: 250 IL6 to SBC swap I'm one who loves the 6 but if I had to replace an engine,I would probably save the money by going to a350 also.The towers and placement are different in the V-8 truck(BB and SB also).The tranny works,IIRC so does the bellhousing and clutch but you will need a flywheel.The bellcrank and mounts for it are different for the V-8 clutch.I'm sure that's not all but someone will probably point out my shortcomings. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

08-18-2012, 08:59 PM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: 250 IL6 to SBC swap ttt It's been many years since I converted mine but I remember the drive shaft was different in length also. I used a complete 350 engine and 350 transmission off a 75 Impala. My advice is to see if you can find an old clunker 68-72 if you can otherwise it's going to take some time to locate what you need. Be sure and check this site's parts for sale section, ebay and even Craigs lists in your state for cities near you. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

08-19-2012, 02:32 AM	#5
TheSeeker Registered User Join Date: Dec 2009 Location: Glendale, AZ Posts: 337	Re: 250 IL6 to SBC swap OK. Weekend got away from me so I am just gettin back on this now. Thanks for the help guys. Anybody else have any pointers?



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