74 GMC Turbo LS Repower

[frankenstien]

Figured id start a build thread, maybe encourage me to take more pics of the project

I have had this truck for about 12 years, Bought it from a gas station in Ester Alaska, it was parked since 83-84, in pretty rough shape. Had it towed home, started in on it. It started out as a Sierra Grande 1500 with a 350/th350/203, a year later it was a 383/th350/205.

Drove it on my wedding day, fast forward 11 years, sold off the motor trans and t case, all torn apart, even more rust, wanted some more power in it, so thought id do a "cheap" turbo ls swap

Pics the day i got it 10-10-2007, then in july(ish)2008

 

[frankenstien]

Truck last summer after I removed the rotted out bed and replaced with a flat bed I got from a parts truck, last pic is from late September of this year when I pushed it into the garage.

 

[frankenstien]

So far I picked up a 2008 LC9 5.3 out of a rolled Silverado 1500, as well as a 6L80E out of a 2009 Silverado as well as the Advance Adapter to bolt it up to a long input np205 that was ont he back of a th400. which I got from the same parts truck I got the flat bed from.

picked up a used turbo manifold and On3 76/75 turbo, price was right, should do what i want it to for now.

I'll be perfectly honest, I've never done a turbo motor before, or a fuel injection swap, so I am using google fu and winging alot of it. I have done this fairly cheap, as I do not want to grenade a nice built motor, once i get every thing dialed in I will replace some of the stuff with better parts. Its just a summer toy, so my goal is if needed, just replace motor/trans with junkyard replacements if needed.

I'd like to see 600hp at the tires, which i think is possible with the stuff i have, but we will have to see.

 

[frankenstien]

Here's some of the motor, motor was in rough shape, i believe it had 160k on it, but not sure. It was burning coolant, valve seats were pitted, pitting on top of the pistons, pretty sure the oil was never changed. ended up having to have the heads milled .003, as well as a 3 way valve job, they are 243 heads.

Number 7 cylinder was in rough shape, ended up dingle ball honing the cylinders, picked up a set of stock size pistons w/rings off ebay for 100$, they are from the later LC9 which is 9.6:1 vs the earlier ones were 9.9:1, other than #7 the rest looked good, all the rod bearings also looked good

got a dod delete kit from Little John Motor Sports as well as

Stage 2 4.8 turbo cam
DOD delet kit
ls7 lifters
lifter trays
multi layer head gaskets
ARP head bolts
push rods
.660 valve springs

 

[Tothemax]

should have plenty of power good choice 6L80E

 

[frankenstien]

should have plenty of power good choice 6L80E

Hope so! i figured the 4:1 1st gear and 2 over drives will also make the truck drive a little better

 

[SmokeShow]

sweet build! :woott:

 

[frankenstien]

got a little bit of work done yesterday, got the old ac box removed from the firewall, the thing takes up so much space, so I ordered a delete box. It didn't fit all that great especially in the top middle by the heater hose outlets, had about a 1/2'' gap. I used some foam weather strip to seal the box to the firewall(still have to trim some of the extra sticking out.

There's a undercoating/something on the firewall that was 0 fun to deal with, but i gained a lot of room with the new box, which where the turbo is going to sit, will b good for the exhaust piping

 

[frankenstien]

took about a week off work, had some time to get some stuff done.

got the motor and trans bolted together, swung them in as a unit, got it all centered and set where i wanted it, the motor trans combo is a little longer than the SBC and th350, i was able to use the 2 rear cross member bolt holes for the old combo for the front bolt holes of the new cross member(if that makes sense) I used the Dirty Dingo motor mounts, the stock th400/250 cross member from the 80's and an Energy suspension transmission mount.

 

[frankenstien]

I bought a timing cover with turbo drains already welded in, could only find one that 2 welded in, one on each side. well the driver side that im not using is capped, and in the way of the power steering/alternator bracket, so i cut a notch in the bracket and massaged the bolt hole boss on the bracket, and it fits with clearance on all sides, the power steering lines will be tight, but will work

 

[NC-smokinlmm]

Nice build! I'd would just skip the arp bolts, stock are fine. Those 243's love boost, that's what I'm running on mine. 600 rwhp will be easy with 12 to 15 lbs of boost, I'm pushing over 600 now on 14#'s and there is more left in it. The 6l80 is perfect for what your doing just make sure you get a tuner who knows these things bc they can implode if not tuned properly...

 

[frankenstien]

Nice build! I'd would just skip the arp bolts, stock are fine. Those 243's love boost, that's what I'm running on mine. 600 rwhp will be easy with 12 to 15 lbs of boost, I'm pushing over 600 now on 14#'s and there is more left in it. The 6l80 is perfect for what your doing just make sure you get a tuner who knows these things bc they can implode if not tuned properly...

I probably over did it in some areas, ARP bolts are already in, I've never built one of these motors before, seemed like cheap insurance? The 6L80E I have is from a 2009 with 79k miles, so it doesn't have all the updated parts the 2010's got, so I'm not expecting a long life out of this one.

As for tuning, A while ago I contacted the same people you have your truck tuned by to see if they would be able/even interested in tuning it remotely. which the guy I made contact with said it was doable, would help if i had access to a dyno, which i might have to see when I get there

 

[frankenstien]

front shot of the motor, you can see how tight the lines are between the frame and the power steering pump, and how close it is to the factory in/out

 

[frankenstien]

Also swapping out the bench seat for some seats out of a 2001 silverado 2500, the seats were in a truck that was wrecked, EMT's cut the seat belt, found a set with nicer covers and intact seat belts, so took the 2 sets and made one good set, got the cab all stripped down

 

[NC-smokinlmm]

Cool, yea, Jay is the shit. I that should be one fun ride!