99 Vortec Motor and tranny swap????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

yooper · 04-09-2004, 11:31 AM

I was wondering what it would take to swap a vortec 350 and a 4L60E from a 99 tahoe into my 71 2WD.

The motor is complete with computer, wiring, starter, alternator. Everything I should need.

Does anybody know how the motor mounts would work? How the tranny mounts would fit? I would imagine I will need to have a different length drive shaft.

What can I do to get the spedometer to work?

All help is appreciated.

Thanks

stelth2002 · 04-09-2004, 12:14 PM

They sell adapters to make the speedo work, but i think you might have to make your own motor mounts.

mcmlxix · 04-09-2004, 12:20 PM

I think 99 was based on the LS1 motor. check with www.hotrodlane.cc They should have have all the answers...

lukecp · 04-09-2004, 01:43 PM

You would need a wirign harness for the EFI, i'm thinking Painless makes this. Check in Summit, they carry their wiring harnesses.

I don't think the motor mounts would be any differet than a regular SBC motor mount setup, because it still is a regular old SBC.

yooper · 04-09-2004, 03:15 PM

I was thinking my only big problem will be mounting the motor and tranny. THe place I am looking at getting this from is going to include the wiring. The motor is a 99 but I dont think its the LS style because its still a 5.7L not the 5.3L.

Is there anybody on here that has done this swap?

tomsC10R · 04-09-2004, 07:38 PM

Hey Yooper,
Are you still planning on doing that swap before the Power Tour? Are you still planning on going?

Wish I could help answer some of your questions...

If it is a Vortec and not the LS style, it'll probably be easier mounting it.

Good luck!!

FuelCellGuy · 04-09-2004, 08:07 PM

the in tank pump.

Tx Firefighter · 04-10-2004, 08:42 AM

It's a typical 350. No fancy mounting required. The later LS type of engines like 5.3 are the weird ones.

Use the Painless harness. Like was said, the speedometer and fuel system are the challenges, not the mounting.

incoma · 04-10-2004, 08:53 PM

Tx Firefighter is correct. The TBI engine will bolt right onto the old mounts. The tranny won't drive your spedometer though. You'll need to get a converter for that, or play with the tranny to get a mechanical unit on it. You'll need an electric fuel pump to feed the TBI also. I have heard that painless wiring is painful from several people. I'd read many posts that say www.speartech.com or www.jimsperformance.com will give you better service and quality.

*1972C10* · 04-10-2004, 10:33 PM

I dont recall where i seen them but i saw some adaptors to drive a mechanical speedo with an electric sender. As i recall they were around 500 dollars thou.

acloco · 04-10-2004, 10:51 PM

Avoid the 500 dollar electronic speedo/mechanical adapter....and see if you can snag the gauge pod from the Tahoe as well.....problem solved!

Other than that.....darn near bolt in. You will have to do something for a rear trans mount/crossmember....but...your current crossmember can be used...but moved back just a bit. Stock frame to transmission linkage will work as well. Make sure you get the yoke from the 4L60 as well.

You also have to do something with the engine oil cooler on the newer engine....either add to your existing truck...or forget it.

AND....most importantly...change the intake manifold gaskets on the 99 engine while you have it out......and use green coolant when you install in your new truck.

The fuel pump is no problem...there are numerous aftermarket pumps that will work. The factory pumps are expensive to replace (350-490 - just for the part).

Good luck!

FuelCellGuy · 04-10-2004, 11:04 PM

makes an electronic speedo for $189.

incoma · 04-10-2004, 11:37 PM

I just measured for a 4L60E in my 70 model. I had a 350 turbo, and had to move the cross member 1.75" further back.

yooper · 04-11-2004, 08:33 PM

Thanks for the responses. I think I'm a lot more confident about this now and I may go for it.

Tim240Z · 02-25-2005, 06:58 PM

ressurecting an old thread here......
I am going to put in a 5.7/4L60E Vortec from a 99 Suburban (63k miles on it) into my 71.
I've searched and search but came up empty. Does anyone have a pinout diagram for the PCM? I have converted a 94 F-body LT1-T56 harness to run in another car, so I should be able to manage this one too, but will need to find out what all the wires go to......
Can anyone help with that?
Also, are there any editting tools for this PCM? I used TunerCat for the LT1, but this PCM doesn't appear to be supported by Tunercat, or LS1 Edit. Any Ideas? I think I will need to over-ride the VATS system to bypass the in-key chip recognition?

Any help would be highly appreciated.....
Thanks,
Tim

incoma · 02-25-2005, 08:16 PM

I'd recommend the ls1truck.com or ls1tech.com websites. You should be able to find someone there with a pinout.

04-09-2004, 11:31 AM	#1
yooper Registered User Join Date: Nov 2001 Location: yoop Posts: 54	99 Vortec Motor and tranny swap????? I was wondering what it would take to swap a vortec 350 and a 4L60E from a 99 tahoe into my 71 2WD. The motor is complete with computer, wiring, starter, alternator. Everything I should need. Does anybody know how the motor mounts would work? How the tranny mounts would fit? I would imagine I will need to have a different length drive shaft. What can I do to get the spedometer to work? All help is appreciated. Thanks

04-09-2004, 12:14 PM	#2
stelth2002 Young Gun wth Fast Inline Join Date: Jan 2002 Location: Idaho Posts: 1,475	They sell adapters to make the speedo work, but i think you might have to make your own motor mounts. __________________ 1967 Chevrolet LWB with built 292! 415 ft. lbs of torque, 4 speed :O with 27% overdrive too, 3.73 Posi. Frame and body done... getting painted!!!

04-09-2004, 12:20 PM	#3
mcmlxix Collector of Projects Join Date: Apr 2003 Location: Las Vegas Posts: 3,106	I think 99 was based on the LS1 motor. check with www.hotrodlane.cc They should have have all the answers... __________________ Rich 1972 K5 Blazer CST Click HERE D60 BIG BRAKE UPGRADE Click HERE

04-09-2004, 01:43 PM	#4
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	You would need a wirign harness for the EFI, i'm thinking Painless makes this. Check in Summit, they carry their wiring harnesses. I don't think the motor mounts would be any differet than a regular SBC motor mount setup, because it still is a regular old SBC. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

04-09-2004, 07:38 PM	#6
tomsC10R Registered User Join Date: Nov 2003 Location: Wisconsin Posts: 281	Hey Yooper, Are you still planning on doing that swap before the Power Tour? Are you still planning on going? Wish I could help answer some of your questions... If it is a Vortec and not the LS style, it'll probably be easier mounting it. Good luck!! __________________ Tom 1968 C10 LWB. 402 BB, Holley MPI, 700R4. 4wheel Hydroboost Disk Brakes.

04-09-2004, 03:15 PM	#5
yooper Registered User Join Date: Nov 2001 Location: yoop Posts: 54	I was thinking my only big problem will be mounting the motor and tranny. THe place I am looking at getting this from is going to include the wiring. The motor is a 99 but I dont think its the LS style because its still a 5.7L not the 5.3L. Is there anybody on here that has done this swap?

04-09-2004, 08:07 PM	#7
FuelCellGuy FUEL CELL GURU Join Date: Aug 2003 Location: Mineola, Texas Posts: 993	Don't forget... the in tank pump.

04-10-2004, 08:42 AM	#8
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	It's a typical 350. No fancy mounting required. The later LS type of engines like 5.3 are the weird ones. Use the Painless harness. Like was said, the speedometer and fuel system are the challenges, not the mounting. __________________ I'm on the Instagram- @Gearhead_Kevin

04-10-2004, 08:53 PM	#9
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	Tx Firefighter is correct. The TBI engine will bolt right onto the old mounts. The tranny won't drive your spedometer though. You'll need to get a converter for that, or play with the tranny to get a mechanical unit on it. You'll need an electric fuel pump to feed the TBI also. I have heard that painless wiring is painful from several people. I'd read many posts that say www.speartech.com or www.jimsperformance.com will give you better service and quality. __________________ "Green Monster" (Red Sox fan) 1970 GMC survivor, 350/200 4R, 3.42 rear gears, 2.5/4 drop, ECE disc brake conversion, powder coated suspension

04-10-2004, 10:33 PM	#10
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	I dont recall where i seen them but i saw some adaptors to drive a mechanical speedo with an electric sender. As i recall they were around 500 dollars thou.

04-10-2004, 10:51 PM	#11
acloco Registered User Join Date: Apr 2004 Location: Nebraska Posts: 335	Avoid the 500 dollar electronic speedo/mechanical adapter....and see if you can snag the gauge pod from the Tahoe as well.....problem solved! Other than that.....darn near bolt in. You will have to do something for a rear trans mount/crossmember....but...your current crossmember can be used...but moved back just a bit. Stock frame to transmission linkage will work as well. Make sure you get the yoke from the 4L60 as well. You also have to do something with the engine oil cooler on the newer engine....either add to your existing truck...or forget it. AND....most importantly...change the intake manifold gaskets on the 99 engine while you have it out......and use green coolant when you install in your new truck. The fuel pump is no problem...there are numerous aftermarket pumps that will work. The factory pumps are expensive to replace (350-490 - just for the part). Good luck!

04-10-2004, 11:04 PM	#12
FuelCellGuy FUEL CELL GURU Join Date: Aug 2003 Location: Mineola, Texas Posts: 993	Autometer.... makes an electronic speedo for $189.

04-10-2004, 11:37 PM	#13
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	I just measured for a 4L60E in my 70 model. I had a 350 turbo, and had to move the cross member 1.75" further back. __________________ "Green Monster" (Red Sox fan) 1970 GMC survivor, 350/200 4R, 3.42 rear gears, 2.5/4 drop, ECE disc brake conversion, powder coated suspension

04-11-2004, 08:33 PM	#14
yooper Registered User Join Date: Nov 2001 Location: yoop Posts: 54	Thanks for the responses. I think I'm a lot more confident about this now and I may go for it.

02-25-2005, 06:58 PM	#15
Tim240Z Senior Member Join Date: Jan 2005 Location: LAX area, So Cal Posts: 499	ressurecting an old thread here...... I am going to put in a 5.7/4L60E Vortec from a 99 Suburban (63k miles on it) into my 71. I've searched and search but came up empty. Does anyone have a pinout diagram for the PCM? I have converted a 94 F-body LT1-T56 harness to run in another car, so I should be able to manage this one too, but will need to find out what all the wires go to...... Can anyone help with that? Also, are there any editting tools for this PCM? I used TunerCat for the LT1, but this PCM doesn't appear to be supported by Tunercat, or LS1 Edit. Any Ideas? I think I will need to over-ride the VATS system to bypass the in-key chip recognition? Any help would be highly appreciated..... Thanks, Tim __________________ 1972 Suburban C20 454/TH700R4, eaton-corporate 4.10 (looking for 3.7) Sold: 71 Cheyenne 20 Installed a 99 5.7L L31/4L60E from Suburban 1500 (2005)



Register or Log In To remove these advertisements.

02-25-2005, 08:16 PM	#16
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	I'd recommend the ls1truck.com or ls1tech.com websites. You should be able to find someone there with a pinout.

Register or Log In To remove these advertisements.