Vortec 4.8 vs LS1 bellhousing pattern? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

yossarian19 · 12-20-2012, 12:53 PM

Ok, so, I bought the engine & transmission for my truck separately.
The trans I bought, I was assured, came out of an LS1 equiped F-body. 4L60E.
Everything bolted up to my 2002 4.8 just fine, except one hole on the trans that went to an un drilled blank face on the engine. I remember reading somewhere that you def. don't want to drill that hole.
But... is this a Gen I / II transmission? How would I tell the difference? Seems like all Gen III motors should have the same lugs for the bell housing, right? Or do the trucks just have one less bolt in the transmission?

crazy longhorn · 12-20-2012, 02:37 PM

Did your bellhousing have the top (center bolt hole)?

yossarian19 · 12-20-2012, 03:46 PM

Yep, it has the centered / 12'oclock bolt hole. Block mounted starter, too. It really seems right except for why would it have that unusable bolt hole, unless the LS1 has it threaded??

clinebarger · 12-20-2012, 08:31 PM

No Gen III engine has that hole threaded, But all the Auto bellhousing are cast for it, T56 bellhousing are not cast with the hole.
If you have the top center hole....Odds are you have the correct Trans.

There should be a sticker on the top of the trans case, Give me the 4 large print numbers, I can narrow down what the Trans came from.

12-20-2012, 12:53 PM	#1
yossarian19 Registered User Join Date: Sep 2011 Location: Nevada City, CA Posts: 908	Vortec 4.8 vs LS1 bellhousing pattern? Ok, so, I bought the engine & transmission for my truck separately. The trans I bought, I was assured, came out of an LS1 equiped F-body. 4L60E. Everything bolted up to my 2002 4.8 just fine, except one hole on the trans that went to an un drilled blank face on the engine. I remember reading somewhere that you def. don't want to drill that hole. But... is this a Gen I / II transmission? How would I tell the difference? Seems like all Gen III motors should have the same lugs for the bell housing, right? Or do the trucks just have one less bolt in the transmission?

12-20-2012, 02:37 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Re: Vortec 4.8 vs LS1 bellhousing pattern? Did your bellhousing have the top (center bolt hole)? __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

12-20-2012, 03:46 PM	#3
yossarian19 Registered User Join Date: Sep 2011 Location: Nevada City, CA Posts: 908	Re: Vortec 4.8 vs LS1 bellhousing pattern? Yep, it has the centered / 12'oclock bolt hole. Block mounted starter, too. It really seems right except for why would it have that unusable bolt hole, unless the LS1 has it threaded??

12-20-2012, 08:31 PM	#4
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: Vortec 4.8 vs LS1 bellhousing pattern? No Gen III engine has that hole threaded, But all the Auto bellhousing are cast for it, T56 bellhousing are not cast with the hole. If you have the top center hole....Odds are you have the correct Trans. There should be a sticker on the top of the trans case, Give me the 4 large print numbers, I can narrow down what the Trans came from. Attached Images

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