Vortec 6.0 Liter Swap to 8.1 Liter Questions

panheadsully · 01-10-2009, 08:14 PM

Hello,
I'm looking at swapping my 6.0 Liter with an 8.1 Liter Vortec engine. I have a 2006 1500HD. I was wondering if my truck's bolt pattern on the transmission would bolt up to the 8.1 block. They say the 1500HD has the HD Transmission, but I don't know if it has the bolt pattern for the big block. It is an automatic.

I don't seem to get the performance out of the 6 liter. It's rated at 300HP and 366 Torque. It drinks fuel like crazy. I wouldn't mind sacrificing one for the other, but this one stinks all the way around.

Any suggestions on this swap would be very helpful.

Thanks

mudseeker · 01-10-2009, 09:00 PM

i guess the first queation should be, what trans do you have in the truck right now?

panheadsully · 01-10-2009, 10:41 PM

Hydramatic 4L80E is what wikipedia says for the 1500HD.

436'd skylark · 01-10-2009, 10:50 PM

yeah it eill bolt up. the motor mounts- not so much!

panheadsully · 01-10-2009, 10:54 PM

Any suggestions on that? What other issues do you forsee? Are there motors mounts you can bolt on, or is there cutting and welding involved.

Your thoughts are appreciated.

leolkfrm · 01-11-2009, 06:23 AM

the 8.1 is a lot more weight, so springs will sag. You have a truck with a 5 yr warranty that will be gone! If you want a 1/2 ton toy look for one of the old 454ss and build it! or take yours and upgrade it, lots of deals right now

stumpuller454 · 01-11-2009, 09:54 PM

You may gain HP but definatley not fuel economy, supercharger should net you 150hp extra and a possible 1mpg decrease... Trade the truck if your really set onit, or build a 6.0l and custom tune it,

merlin5577 · 01-12-2009, 03:22 PM

The 8.1L came with the allison 1000 5speed. The 6.0 came with the 4L80-E. I do not beleive it will bolt up. You most likely need to buy an adaptor plate. You will need a new torque converter, PCM/ECM, motor mounts, and transmission controller. Not to mention the suspension modifications. IMO you would be much better off selling the truck and just buying one with an 8.1L. Or, modifying the 6.0 for more power.

see error · 01-12-2009, 06:26 PM

i dont believe the swap will be a easy one it is not plug and play like the 5.3 to 6.0 is i would go with a supercharger as stated earlier a lot of the 8.1l also have issues with excessive oil consumption and poor fuel economy just my 2 cents

leolkfrm · 01-12-2009, 06:38 PM

poor economy yes, oil consumption NOT! your thinking mIV engines 8.1 is a strong runner

01-10-2009, 08:14 PM	#1
panheadsully Junior Member Join Date: Jan 2009 Posts: 5	Vortec 6.0 Liter Swap to 8.1 Liter Questions Hello, I'm looking at swapping my 6.0 Liter with an 8.1 Liter Vortec engine. I have a 2006 1500HD. I was wondering if my truck's bolt pattern on the transmission would bolt up to the 8.1 block. They say the 1500HD has the HD Transmission, but I don't know if it has the bolt pattern for the big block. It is an automatic. I don't seem to get the performance out of the 6 liter. It's rated at 300HP and 366 Torque. It drinks fuel like crazy. I wouldn't mind sacrificing one for the other, but this one stinks all the way around. Any suggestions on this swap would be very helpful. Thanks

01-10-2009, 09:00 PM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	i guess the first queation should be, what trans do you have in the truck right now? __________________ i'd rather be hunting

01-10-2009, 10:50 PM	#4
436'd skylark Senior Member Join Date: Mar 2007 Location: Buffalo Ny Posts: 661	yeah it eill bolt up. the motor mounts- not so much! __________________ Joe 89 K2500 Chevy, Wee-Oh-five 285K miles, completly rebuilt needs a motor, bad 1962 IHC Scout All Wheel Drive (Scout speak for locking axles) 152 ci, dana everything else

01-11-2009, 06:23 AM	#6
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	the 8.1 is a lot more weight, so springs will sag. You have a truck with a 5 yr warranty that will be gone! If you want a 1/2 ton toy look for one of the old 454ss and build it! or take yours and upgrade it, lots of deals right now __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

01-11-2009, 09:54 PM	#7
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	You may gain HP but definatley not fuel economy, supercharger should net you 150hp extra and a possible 1mpg decrease... Trade the truck if your really set onit, or build a 6.0l and custom tune it, __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

01-10-2009, 10:41 PM	#3
panheadsully Junior Member Join Date: Jan 2009 Posts: 5	Hydramatic 4L80E is what wikipedia says for the 1500HD.

01-10-2009, 10:54 PM	#5
panheadsully Junior Member Join Date: Jan 2009 Posts: 5	Any suggestions on that? What other issues do you forsee? Are there motors mounts you can bolt on, or is there cutting and welding involved. Your thoughts are appreciated.

01-12-2009, 03:22 PM	#8
merlin5577 Banned Join Date: Nov 2008 Posts: 675	The 8.1L came with the allison 1000 5speed. The 6.0 came with the 4L80-E. I do not beleive it will bolt up. You most likely need to buy an adaptor plate. You will need a new torque converter, PCM/ECM, motor mounts, and transmission controller. Not to mention the suspension modifications. IMO you would be much better off selling the truck and just buying one with an 8.1L. Or, modifying the 6.0 for more power.

01-12-2009, 06:26 PM	#9
see error Senior Member Join Date: Jul 2008 Location: tallahassee, fl Posts: 169	i dont believe the swap will be a easy one it is not plug and play like the 5.3 to 6.0 is i would go with a supercharger as stated earlier a lot of the 8.1l also have issues with excessive oil consumption and poor fuel economy just my 2 cents __________________ 2004 gmc 1500 cc 4x4

01-12-2009, 06:38 PM	#10
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	poor economy yes, oil consumption NOT! your thinking mIV engines 8.1 is a strong runner __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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