LT1 internally balanced? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

supermuble · 02-19-2007, 02:26 AM

I am considering purchasing a 1994 LT1 350 from a friend. He rebuilt the engine himself, oversize pistons, new connecting rods, and a new crankshaft. All brand new OEM replacement parts. The machine shop that did the work said it didn't need to be balanced that the parts were "factory" spec. The engine is hooked to an automatic transmission, previously a 4L-60E, now a 700R4.

Are these engines internally balanced or externally balanced?

The engine runs and it is smooth, no noticeable vibrations can be felt or heard, but I don't want to cause long term damage.

fastwillie 696969 · 02-19-2007, 02:39 AM

i think there internal bal. but what are oversize pistons ?

FarmTruk · 02-19-2007, 02:53 AM

I believe when the LT1's switched to 1 pc rear main seals, the General changed to internal balance. However, the internals are lightweight, so any changes, such as "over-size pistons" could throw the factory balance off.

GREASEMONKEY72 · 02-19-2007, 05:19 AM

over sized pistons would be if the block is .30 over or more then the stock pistons dont fit and you need new pistons that are bigger than stock

cooters · 02-19-2007, 10:41 AM

all 350s were internally balanced, 400s were enxternaly balanced (smallblock) however balancing is nice but not required in your case unless you are going to rev it to 6000

02-19-2007, 02:26 AM	#1
supermuble Registered User Join Date: Nov 2006 Location: Spokane, WA Posts: 12	LT1 internally balanced? I am considering purchasing a 1994 LT1 350 from a friend. He rebuilt the engine himself, oversize pistons, new connecting rods, and a new crankshaft. All brand new OEM replacement parts. The machine shop that did the work said it didn't need to be balanced that the parts were "factory" spec. The engine is hooked to an automatic transmission, previously a 4L-60E, now a 700R4. Are these engines internally balanced or externally balanced? The engine runs and it is smooth, no noticeable vibrations can be felt or heard, but I don't want to cause long term damage. __________________ I learned turbocharging the hard way. I turbocharged an ancient import! The theory still applies to the Chevy engine. http://www.angelfire.com/planet/celica

02-19-2007, 02:39 AM	#2
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	Re: LT1 internally balanced? i think there internal bal. but what are oversize pistons ? __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

02-19-2007, 02:53 AM	#3
FarmTruk In Memoriam... Join Date: Nov 2006 Location: Wallburg, NC Posts: 1,216	Re: LT1 internally balanced? I believe when the LT1's switched to 1 pc rear main seals, the General changed to internal balance. However, the internals are lightweight, so any changes, such as "over-size pistons" could throw the factory balance off. __________________ '68 C10 SWB 307ci 2BBL *FarmTruk Pics Here* *"You know, doing what is right is easy. The problem is knowing what is right."*

02-19-2007, 05:19 AM	#4
GREASEMONKEY72 Registered User Join Date: Aug 2006 Location: Bakersfield,CA Posts: 7,893	Re: LT1 internally balanced? over sized pistons would be if the block is .30 over or more then the stock pistons dont fit and you need new pistons that are bigger than stock __________________ -steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME

02-19-2007, 10:41 AM	#5
cooters Senior Member Join Date: Oct 2006 Location: Edmonton Alberta Posts: 458	Re: LT1 internally balanced? all 350s were internally balanced, 400s were enxternaly balanced (smallblock) however balancing is nice but not required in your case unless you are going to rev it to 6000



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