prican_2000

iTrader: (1)

OK guys I have been reading and reading and searching but I cannot find my specific scenario (newer truck-GMT 800 to install the older engine LM7) so I figured I would ask some questions. but first let me give you all a lil background so you can see that I have done some extensive research. Forgive me if this has been asked a million times over - if I missed a post please feel free to link me and I will go read it.

I bought a 2005 Silverado RCLB 2WD Work truck with the puny 4.3 ltr V6 that has a million miles on it (actually 249K miles) and I swear its running on 3 cyl even after I did a full tune-up on it. I'm also pretty sure its "NOT" the original motor as it has a crank driven fan "AND" electric fans mounted on the Radiator. Anyways I was able to find a "GREAT" deal (and purchased) a complete LM7 out of a 99 Silverado with under 70K miles on it. Complete with wiring harness, computer, intake, etc.

I have never been involved in this amount of work (never done an engine swap) although I have done a transmission swap in a Chrysler 300 so I am not afraid of doing work, just have a fear of the "unknowns" and I like to do all the research that I can and buy all the parts needed for a smooth process, anyways I have been in and out of this AWESOME V6 to V8 swap thread:
http://www.ls1truck.com/forums/v8-conve ... ide-6.html

I just want to make sure that I cover everything before I start taking the motor out to install the new motor. I hate having to stop work because I am missing parts, etc. but I am still unclear on a few things and I hope you guys can address of point me in the right direction.

Luckily for me 03 and ^ V6 trucks were DBC and the LM7 is also DBC - so that should be straight forward.

I purchased new motor mounts and I am on the search for the Drivers side 2WD V8 Frame to motor mount.

I am also looking for the truck Alternator/PS Pump Bracket as the motor did not include this.

Now onto my questions:

As far as transmission (M30 - 4L60E) - I believe that the new motor will bolt right in but I am unsure if there will be issues with the Bellhousing as some people have said that the bellhousing will need to be replaced - can anyone confirm or deny this?

As far as Accessories - will the current V6 power steering pump and the alternator swap over once I get the V8 Acc Bracket?

As far as the computer - since I have a 2005 and I am installing a 99 LM7 will I have issues with the wiring harness from the 05 working/(Pinout issues/backward compatibility from 05-99) being compatible to control the necessary items? Would I still need to send out for a tune that requires my VIN to transfer over, or will the 5.3 Computer communicate just fine with 05 electronics?

As far as the fuel system - I believe that my 05 has the returnless fuel system, so if this is true I shouldn't have any issues with the LM7 since its also has a returnless fuel rail - correct? or do I have to do anything additional - saw something about Corvette filter??

As far as heater hoses - I have not seen anything covered on that - can anyone shed some light on that? would the V6 heater hoses work just fine or do I need V8 Heater hoses?

I know that the A/C compressor is different and I'm not really concerned about that at this time - just want to get the motor in and running. I will probably run it without any A/C at all.

Thanks in Advance for your help - I am sure there will be a lot more questions to come. some pics attached for your viewing pleasure.

1FastBrick

iTrader: (17)

The 99-02 electronics will not work in a 03-07-classic truck. You will need to modify a harness to work for your specific application.

99-02 uses a 512KB ECU
03-07 classic uses a 1MB ECU

The Vans used a cable driven TB up tell they changed over to the E38 PCM combo around 08-09?

As far as the transmission I believe the convertor is different as well as the input shaft.

99-03 were return style on the V8's 04-07 classic were returnless. I would just get a fuel rail from a returnless vehicle.

prican_2000

iTrader: (1)

WOW 1FastBrick!!! THANK YOU!!!! for the info. I got some follow-up questions.

So even if I have all the wiring harnesses and ECM from the 99 I would still have to modify the 05 wiring? I would've thought with all the wiring harnesses and computers that this would've been a Plug n Play affair dammit!

On the transmission issue where could I find out if in fact the converter and the input shaft are different?

On the fuel, I have attached a pic (of the 4.3 currently in the truck) so you can see what I see but I do not see a return style fuel or am I missing something?

I also attached a pic of the (99) 5.3 engine and if you are saying that the 99-03 were return style fuel - I don't see it, it looks to me that it is the same as the 4.3 and there is only 1 fuel line from the truck just install right onto the 5.3 or again am I missing something? there is no other "fuel" lines coming off the rails on the new motor.

I'm Sorry if these questions seem stupid/ignorant but I have never done an Engine Swap before so trying to gather as much information as possible before I jump head first.


Thanks Again

prican_2000

iTrader: (1)

oppps sorry got click happy.

Attached is the pic of the 5.3 fuel line - that is the "ONLY" fuel line that I can see. Again unless I am missing something here.

if you need any additional pics let me know and i'll post them.

Thanks

prican_2000

iTrader: (1)

Finally getting to have some time to drop the 5.3 in and I realized that I was missing the motor - to - Frame mount bolts. because as I was removing the V6 Frame mounts the bolts were seized up and all "SNAPPED". so I am in need of the information needed for those bolts. I have searched online and cannot find anything definitive - hoping you guys can help. they are (3 bolts on each side) the bolts that attach the motor mounts to the Frame mounts - they have a 15mm hex head but I need to know the threads size, bolt size, pitch, etc so I can order.

Thank You

RedXray

I'm doing the v6 to 6.0 swap now myself. Remove one of the mount to engine bolts and see if they're the correct thread and length to fit the mount to frame. If so the part number for that bolt is 11609475. The exploded diagram doesn't say exactly which hole the bolt fits... my guess both. If that bolt works check the links below. Check if the bolts in the v6 block are the correct threads?

On the transmission your flywheel and converter from the v6 should work. The fuel line looks kinda odd to me. The 99 5.3 is a return setup with two lines coming off the drivers side fuel rail. The pic you posted I only see one line coming off that rail. Look and see if there is a vacuum regulator on the drivers side fuel rail. If not you have a returnless fuel rail and are good to go with the 05 returnless system.

This seller only has two bolts.

https://www.ebay.com/itm/GM-OEM-Engi...BaLDz5&vxp=mtr

All six but used (kinda high too)

https://www.ebay.com/itm/2003-Chevy-...xaXtAC&vxp=mtr

prican_2000

iTrader: (1)

ohhh man I forgot I had this thread up and that FastBrick answered some questions about incompatibilities between the 99 to 05 back in 2016!!!! although I've had the engine waiting to get installed that long - it feels like the truck has also been down that long as well but that's not the case - I did not start on the swap until Oct 17 and then my schedule got so hectic that I just finally installed this month. about the bolts: they are 10mm x 1.50 Standard Thread - hopefully that will help someone else looking for that info.

You are correct about the transmission flywheel and converter - it all bolted up and worked (well it all bolted up, whether it works the consensus on that is still out) but a tip for those doing this swap in the future: install the 1st flexplate to converter bolt and "DO NOT FULLY TIGHTEN" just get the bolt in snug then proceed to the next 2 bolts. After all 3 bolts are on then you can fully tighten. I noticed that when I tighten the 1st bolt then I had a hard time getting the final bolt on because the alignment of the flexplate and converter was slightly off by just a hair - just enough to not allow you to thread it in.

as far as the Fuel - I haven't crossed that bridge yet. as you can see from my other post I am having wiring harness issues that I am trying to resolve but my initial on the fuel: the motor has the rear feed line that will plug into the OEM trucks line but then there is what I think is a Fuel Pressure Regulator (hopefully the pic loads) because it has an electronic connection on it. and then the motor has a return line in the front??? Although I thought that I read in multiple places that the fuel return line was on the drives side fuel rail??? - I think- I dunno. Hopefully I am able splice and make those 2 work together.

1FastBrick

iTrader: (17)

That is the vacuum solenoid for the Evap system.

The fuel pressure regulator is on the driver side fuel rail and has a vacuum hose attached to it.

1FastBrick

iTrader: (17)

This is the fuel pressure regulator.

prican_2000

iTrader: (1)