eng swap

coloradowingnut · 06-01-2009, 09:49 AM

Hi all,
I am new to the forum, and have a question. I have a 1999(old body stlye) gmc k2500 with a vortec 7.4 /(454). The eng is tired and I would like to swap in a vortec 5.7 (350) as I don't need the power of the 7.4 and now want better fuel economy from a 5.7. I have look online a bit and have had no luck on the feasibility of this swap. Please let me know your thoughts on this.
Thanks & Regards,
John

cburcham73 · 06-01-2009, 10:35 AM

by the time you find a motor,tranny ,computer,and accessories,etc. you could have rebuilt the 454,then you could sell it, and buy something better on gas. in other words its alot of work and money.

coloradowingnut · 06-01-2009, 04:13 PM

Thanks for your input. I already have a 96 sierra 4x4 that I would use for the drivetrain.
How feasible is it to convert a 2x4 to a 4x4?

I am in the martket for another truck, but can't seem to find what I want.

ukrkoz · 06-01-2009, 08:25 PM

ok, from several forums i am membering in - don't do this. so far, any mismatched engine swap just caused trouble. you'll have to either swap the whole powertrain and ECM/TCM/BCM, or you'll be harvesting problems.

how bad is your current mpg? you should expect about 17mpg from 5.3 L, no doubt less from 5.7

coloradowingnut · 06-05-2009, 10:18 PM

I am getting about 10mpg in town 13/14 on the highway. It is a 454, not a 5.3 or 5.7. I do have my other truck for parts if needed. Is it more work to put a stronger suspension & axles in a 1500?

hotrodpc · 06-05-2009, 10:31 PM

You are getting that with a tired 454??? Geez Dude !!! What's wrong with that? I'd rebuild the fo fitty fo and run with it !!! I think the money you'd save, and the work will buy you alot of gas to burn and that is great mpg for a BBC in my opinion. Or as suggested, sell the whole truck and buy you another one. Actually a tad newer with the 5.3 will net better power and mpg both. That 5.3 will do everything your 454 will do, but give you about 14 and 19 mpg.

leolkfrm · 06-07-2009, 04:56 PM

put a gear vendors overdrive in it and run it!

gmctrucks · 06-07-2009, 05:17 PM

Quote:

Originally Posted by cburcham73

by the time you find a motor,tranny ,computer,and accessories,etc. you could have rebuilt the 454,then you could sell it, and buy something better on gas. in other words its alot of work and money.

I agree it would be a big headache plus the cost would be a lot.

hotrodpc · 06-07-2009, 09:42 PM

Those gear vendor units are pretty pricey too. I have seem then reasonable used though.

06-01-2009, 09:49 AM	#1
coloradowingnut Junior Member Join Date: May 2009 Posts: 4	eng swap Hi all, I am new to the forum, and have a question. I have a 1999(old body stlye) gmc k2500 with a vortec 7.4 /(454). The eng is tired and I would like to swap in a vortec 5.7 (350) as I don't need the power of the 7.4 and now want better fuel economy from a 5.7. I have look online a bit and have had no luck on the feasibility of this swap. Please let me know your thoughts on this. Thanks & Regards, John

06-05-2009, 10:31 PM	#6
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,167	You are getting that with a tired 454??? Geez Dude !!! What's wrong with that? I'd rebuild the fo fitty fo and run with it !!! I think the money you'd save, and the work will buy you alot of gas to burn and that is great mpg for a BBC in my opinion. Or as suggested, sell the whole truck and buy you another one. Actually a tad newer with the 5.3 will net better power and mpg both. That 5.3 will do everything your 454 will do, but give you about 14 and 19 mpg. __________________ *Winners NEVER Quit , Quitters NEVER Win !!!*

06-07-2009, 04:56 PM	#7
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	put a gear vendors overdrive in it and run it! __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

06-07-2009, 09:42 PM	#9
hotrodpc Senior Member Join Date: Jul 2008 Location: OKC, OK Posts: 3,167	Those gear vendor units are pretty pricey too. I have seem then reasonable used though. __________________ *Winners NEVER Quit , Quitters NEVER Win !!!*

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06-01-2009, 10:35 AM	#2
cburcham73 Senior Member Join Date: Aug 2008 Location: williamsburg virginia Posts: 183	by the time you find a motor,tranny ,computer,and accessories,etc. you could have rebuilt the 454,then you could sell it, and buy something better on gas. in other words its alot of work and money.

06-01-2009, 04:13 PM	#3
coloradowingnut Junior Member Join Date: May 2009 Posts: 4	Thanks for your input. I already have a 96 sierra 4x4 that I would use for the drivetrain. How feasible is it to convert a 2x4 to a 4x4? I am in the martket for another truck, but can't seem to find what I want.

06-01-2009, 08:25 PM	#4
ukrkoz Senior Member Join Date: Feb 2008 Posts: 172	ok, from several forums i am membering in - don't do this. so far, any mismatched engine swap just caused trouble. you'll have to either swap the whole powertrain and ECM/TCM/BCM, or you'll be harvesting problems. how bad is your current mpg? you should expect about 17mpg from 5.3 L, no doubt less from 5.7

06-05-2009, 10:18 PM	#5
coloradowingnut Junior Member Join Date: May 2009 Posts: 4	I am getting about 10mpg in town 13/14 on the highway. It is a 454, not a 5.3 or 5.7. I do have my other truck for parts if needed. Is it more work to put a stronger suspension & axles in a 1500?

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