66 GMC Long to Short LS Swap

[Jferrante]

Good stuff

[SkinnyG]

Make sure you follow the re-coat "window" on the can - Tremclad wrinkles nasty if you re-coat at the wrong time.

(I painted my '77 with Tremclad and a roller - tee hee)

[aggie91]

Nice work so far. Joining in to see it to the end...

[Duncan K]

Got the frame flipped over, kids helped me paint the frame again while the dog supervised.



Pressed out the old trailing arm bushings and installed some new polyurethane ones. Got the rear end painted and started putting the rear suspension back together. Using 5" drop springs and 2" drop blocks. So nice to be working with clean, freshly painted parts and brand new hardware. No more rust and grime!!



Painted the spindles and callipers and put the front suspension together. 2.5" drop spindle and 3" drop springs.



Good buy old drum brakes, hello shiny new disks.



Up until this point everything had been great with this Grand Slam kit from CPP. Bolted up the front wheels and found that the rotor hub doesn't fit the centre hole on the wheel. From all the stories I've read about CPP's customer service I'm not looking forward to getting this sorted out.




Does anyone know what rotors I can use on the CPP spindles that will fit the stock wheel opening? I'm thinking it might just be easier to buy a proper set than deal with CPP and have to ship the old ones back.

Bolted both front wheels up so at least its a roller now. I've got some major positive camber in the front. I'm doubtful that even removing all the shims will correct it. Anyone experience this with a 5.5" drop?



Still have to sort out the rear shock relocation and hook up the steering linkage but I think I'll leave that for later. Plan to tear down the LS and get the block off to the machine shop.

[Pinchecharlie]

Hmm..mine is the same drop and had to have a very large shim pack added to get back to normal? In fact I added longer bolts on the upper control arm and my alignment guy said I barley had enough bolt? So it would be nice if yours will balance out with just a small set? Otherwise I Dunno? Is it the caliper that won't fit in the wheel opening or the rim opening isn't centered on the disc bolt pattern? That would mean the disc bolt pattern was askew right? Always something! Let us know what you find out! Otherwise a lot done!!!! Cool that the kids are game for some work!

[Duncan K]

Originally Posted by Pinchecharlie

Hmm..mine is the same drop and had to have a very large shim pack added to get back to normal? In fact I added longer bolts on the upper control arm and my alignment guy said I barley had enough bolt? So it would be nice if yours will balance out with just a small set? Otherwise I Dunno? Is it the caliper that won't fit in the wheel opening or the rim opening isn't centered on the disc bolt pattern? That would mean the disc bolt pattern was askew right? Always something! Let us know what you find out! Otherwise a lot done!!!! Cool that the kids are game for some work!

Rotor hub is to small for the wheel opening. Not sure if it will be easier to switch rotor or wheels.

[Duncan K]

Started tearing down the 6.0 this afternoon. So far cylinders all look to be in good shape. Got stuck on the balancer, don't seem to have a puller that will work.

[SkinnyG]

The wheels will work perfectly fine not resting on the hub - many aftermarket wheels have larger bores than the hubs they need to ride on, and they are fine.

Just tighten the wheel nuts progressively and evenly, since they are now lug-centric. This may result in some imbalance, but you will know once it's on the road.

[Captainfab]

I agree that you can get away with being lug centric instead of hub centric. I've done it many times. There are no OEM 6 lug rotors that will work. You are stuck with 6 lug aftermarket rotors.

[Duncan K]

Thanks Skinny and Captain, never would have thought it was ok to be lug-centric. I might machine a spacer to slip over the hub on the rotor and bring it out to the proper size. I was already thinking about trying to machine a spacer plate so my stock wheels would clear the callipers. Might try to make one piece that solves both problems.

[Duncan K]

Well a busy spring and summer has kept me out of the shop. A few weeks ago I went to a local show and shine and came across this beauty which got me fired up to get in the shop again!!



Got the ball rolling again with a few small items. Cleaned up and painted the steering linkage. Installed the new power steering box and new steering components on the truck. Got the new front shocks installed as well.



Finished tearing down the motor as well. In the process of cleaning up the block and getting rid of some rust before it goes off to the machine shop.

[Duncan K]

Looking for some opinions on this kit from Summit for my rebuild. Looks decent to me but this is my first motor build.

https://www.summitracing.com/int/par...illocation=int

[Notch1988]

Not sure if that kit would work with your cathedral ports. I thought you were just going to hone it and re-ring using your old pistons? What are your goals with the motor?

[Duncan K]

Originally Posted by Notch1988

Not sure if that kit would work with your cathedral ports. I thought you were just going to hone it and re-ring using your old pistons? What are your goals with the motor?

i think the photo of the kit is just generic and shows rectangular port gaskets. It is listed to fit my year of motor. Was more wondering about the quality of the components. The research I've done sounds like they are decent.

I had originally planned on re-ringing the old pistons but for the price of the new ones I figure i might as well replace them while i have it torn down. Goal for the motor is to make it solid, reliable, and wake it up a little with a new cam.

[Notch1988]

Kit looks good, pretty much everything you need. You installing all the bearings and checking clearances? I always worry about buying a bunch of parts and showing up at the machinists saying, "help me", and I didn't buy from them. But maybe they don't care and are happy to just do the labour.

[Duncan K]

I'll be putting the motor together and checking clearances. Should be dropping the block off at the machine shop tomorrow. I would prefer to buy the parts through the shop but i doubt they will be able to match the price from Summit.

[CousinTone]

Anyone else following Duncan’s build, feel lazy?

[SkinnyG]

Check Rock Auto too. I've found them to be cheaper than Summit, and local shops cannot touch their prices. Even with shipping.

[Notch1988]

I find with a lot of stuff from Summit that, once I do the dollar conversion, Mopac is bang on for pricing.

[Duncan K]

Got the block dropped off at the machine shop. Their prices are pretty good so I think I'll buy all my parts through them. Got to work on modifying the wiring harness using the info from LT1swap.com. Took a few hours to get all the old loom and tape off. Pulled all the unneccesary wires out of the harness.

[1enick72]

Dunkan, do you have a link by chance on where you got the information, looks like you have printed pages for pinouts as well. I've done a number of searches over there and just find people that are talking about doing a swap.

[Duncan K]

Originally Posted by 1enick72

Dunkan, do you have a link by chance on where you got the information, looks like you have printed pages for pinouts as well. I've done a number of searches over there and just find people that are talking about doing a swap.

Head over and check out LT1swap.com, all the info you need to re-work a harness is there including detailed pin outs for the ecm plugs.

This series of videos on YouTube is really helpful as well
https://www.youtube.com/watch?v=RHIVd_SkB9Y&t=710s

[Duncan K]

Finished work on the wiring harness for now. Not going to tape it up and put new loom on until i can lay it out on the motor.

Got the block back from the machine shop along with most of my parts.



I've built a ton of dirt bike engines, but this will be my first vehicle engine. I've been researching clearances on these motors. Crazy how much conflicting info there is out there. Decided to use the clearance numbers i got from the machine shop. after cleaning the block I got the mains installed. Checked the clearances with the plasigauge, and then with a mic and bore gauge. I didn't find the platigauge very accurate or consistent.



Installed the crank and torqued down the main caps



Cleaned up the old pistons and rods, and pulled the old rings off. Picked up a new sleeve of platigauge. Got the new rod bearings installed and checked the bearing clearances. I got much better measurements this time.



Checked the ring gaps and installed the new rings. Got one bank of pistons and rods put in.

[Notch1988]

Looking great man. Any plans for boost?

[Duncan K]

No plans for boost. Just not in the budget right now with all the other stuff i still need for this build.