250ci rebuild - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DaSchlange · 09-29-2010, 11:44 AM

So I am rebuilding a 250 chevy motor and need some tips on how to go about it. This will be built too. I am going to put on it a 4 barrel intake but not sure what carb to put on it. I'm looking at 1 600 holley but don't know if that will be too much. I need ideas on other parts as well such as the cam and crank, shaving the head, what it should be bored to, stuff like that. I'm new to the rebuild game and just need some talented and experienced minds to help me out.

PanelDeland · 09-30-2010, 05:57 PM

The 6 will benefit from better compression.You can mill the head or run different pistons.Some piston choices may be the propane ones for a 250,aftermarket or I believe someone said a 307 or 305 size would work.The 600 carb is a bit big for any but a really wild 6.Most recomend a 390 though I haven't seen many around for sale.The head on a 250 is the weak point(as far as power) due to flowing like molasses.They have plenty of port volume but too much to keep velocity up.HEI is almost a necessity.
I don't like to bore an engine block any more than required but that may also be affected by piston choice since there may only be a few options.Keep in mind that with a 6 you may spend 2-3 times the money for less performance than you would get with a cheaper V8.Parts such as PS,A/C brackets are also a bit harder to locate.If you do add weither of these get the pulleys and if possible tha harmonic dampner.
Try a search and check out the thread on 6 cyl.I think it asks for pics.Lots of good info and some more knowledgeable folk posted in it.

**passthebuck** · 09-30-2010, 08:19 PM

I saw this very cool conversion to get the bolt out of the middle of the intake port. If I was to do any L6 work, this would be part of the build.

YouTube - Part 2 Chevy inline 6 head...

**'68OrangeSunshine** · 10-01-2010, 04:29 AM

You might be happier with the 390 Holley. Both Jegs and Summit list them in their catalogs, but they're not cheap. I used to run the 390 CFM Model 4160 P/N R8007 Holley 4Bbl on an Offy intake with Clifford headers. It ran for about 25 years, but when I rebuilt the engine, I had manifold leak problems and I wasn't sure it had a good sealing base anymore, so I went to the 500 CFM Edelbrock 1404 4Bbl clone of the old Carter AFB.
I'm running a '68 292 L6, bored .030 over, with Badger pistons, Sealed Power chrome/moly rings, bigger intake valves [1.84"], Crane 260H cam, Centerforce II clutch, SM465 tranny, 12-bolt Corp rear with 3.73 Eaton posi rear on a '68 C/10 Stepside.
A good book is Leo Santucci's "Chevrolet InLine Six Cylinder Power Manual." ISBN: 1-931128-15-4.
Some websites to check out:
www.inliners.org
www.stoveboltengineco.com
www.cliffordperformance.net
Good luck.

09-29-2010, 11:44 AM	#1
DaSchlange Registered User Join Date: Sep 2010 Location: Gainesville, MO Posts: 251	250ci rebuild So I am rebuilding a 250 chevy motor and need some tips on how to go about it. This will be built too. I am going to put on it a 4 barrel intake but not sure what carb to put on it. I'm looking at 1 600 holley but don't know if that will be too much. I need ideas on other parts as well such as the cam and crank, shaving the head, what it should be bored to, stuff like that. I'm new to the rebuild game and just need some talented and experienced minds to help me out.

09-30-2010, 05:57 PM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: 250ci rebuild The 6 will benefit from better compression.You can mill the head or run different pistons.Some piston choices may be the propane ones for a 250,aftermarket or I believe someone said a 307 or 305 size would work.The 600 carb is a bit big for any but a really wild 6.Most recomend a 390 though I haven't seen many around for sale.The head on a 250 is the weak point(as far as power) due to flowing like molasses.They have plenty of port volume but too much to keep velocity up.HEI is almost a necessity. I don't like to bore an engine block any more than required but that may also be affected by piston choice since there may only be a few options.Keep in mind that with a 6 you may spend 2-3 times the money for less performance than you would get with a cheaper V8.Parts such as PS,A/C brackets are also a bit harder to locate.If you do add weither of these get the pulleys and if possible tha harmonic dampner. Try a search and check out the thread on 6 cyl.I think it asks for pics.Lots of good info and some more knowledgeable folk posted in it. __________________ 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"

10-01-2010, 04:29 AM	#4
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	Re: 250ci rebuild You might be happier with the 390 Holley. Both Jegs and Summit list them in their catalogs, but they're not cheap. I used to run the 390 CFM Model 4160 P/N R8007 Holley 4Bbl on an Offy intake with Clifford headers. It ran for about 25 years, but when I rebuilt the engine, I had manifold leak problems and I wasn't sure it had a good sealing base anymore, so I went to the 500 CFM Edelbrock 1404 4Bbl clone of the old Carter AFB. I'm running a '68 292 L6, bored .030 over, with Badger pistons, Sealed Power chrome/moly rings, bigger intake valves [1.84"], Crane 260H cam, Centerforce II clutch, SM465 tranny, 12-bolt Corp rear with 3.73 Eaton posi rear on a '68 C/10 Stepside. A good book is Leo Santucci's "Chevrolet InLine Six Cylinder Power Manual." ISBN: 1-931128-15-4. Some websites to check out: www.inliners.org www.stoveboltengineco.com www.cliffordperformance.net Good luck. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 10-01-2010 at 04:30 AM.



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