[455HOGT37]

My plan is to use everything I can from the Yukon, including computers, wiring, and even the fly-by-wire throttle. The main benefit of this is that I will have the entire vehicle to pick over once it is retired (rather than multiple trips to the junk yard). I'm hoping this is feasible because there is so much "pin out" info available, I should be able to modify my own harness. Will sure be more work than a "turn key" product, but it will be much cheaper (throwing out my labor, anyway).

[gto65lvr]

bman

I just wanted to thank you again for all this wonderful info and for keeping our economy alive. IF you think about all the goodies you are buying and the amount of people involved to get them to you I think you just about kept the US open for biz LOL.

You prob. saved over 100 peoples jobs.

[b-man]

Originally Posted by fbrown

I'm at about the same stage you are with my conversion, using almost the same parts, LS3 crate etc. My car however is a 68 Lemans that is being converted to a GTO.

I ordered my wiring harness and computers from Speartech since for one reason or other I didn't like the other aftermarket solutions. The GMPP harness requires special software to tune and is not compatible with OBD2 scanners. It also does not talk to an auto transmission controller. The cost of this solution with a GMPP transmission controller is about nearly $2000.

Mast Motor Sports makes a harness/computer that looks very good on the surface but is not truly OBD2 compatible, supports only VDO CAN gauge and cannot be scanned by an OBD2 scanner. By the time you add the transmission controller you are at nearly $3000.

Speartech make a harness and uses GM computers for both the engine and transmission for $1695. This was the choice I made since it can use any of the standard OBD2 scanners, gauges or tuning software. The Speartech solution will also give you cruse control it you want it, which the other two do not. (Mast tells me the cruse has not been done on their computer and is not a high priority).

The main point of interest here is that your selection of a 4L60E will depend on what controller you use. Speartech tells me that for a 4L60E to work with the LS3 and factory GM controllers (NOT GMPP) that the transmission will have to be configured like it is being installed in a 06 Trailblazer SS and not like the typical Camaro transmission that is commonly used. Apparently the output shaft and control electronics are different.

I also had sticker shock when pricing starters. I have not purchased mine yet.

Thank you for the detailed transmission and wiring harness compatibility info, this is a huge help to me. Now I know how much I'll have to spend on a harness, figured it would be at least $1500. Best of luck on your project.

Originally Posted by gto65lvr

bman

I just wanted to thank you again for all this wonderful info and for keeping our economy alive. IF you think about all the goodies you are buying and the amount of people involved to get them to you I think you just about kept the US open for biz LOL.

You prob. saved over 100 peoples jobs.

I'm more than happy to share whatever info I've been able to 'mine' off of the 'net, and help others figure out what direction they need to go when doing an A-body LSX swap. It's hard to figure out what to do when searching through different threads that have bits and pieces of somewhat vague information. Hopefully I can make this thread a good archive of information as well as interesting reading, with as much great help as I've been receiving from the membership it should be a success.

For as long as I've been involved in this hobby (almost 35 years) I have helped to support a lot of small aftermarket parts companies, and buying new parts from GM can't hurt either.

There's lot of good stuff for our cars made here in the USA, Canada and by our Aussie friends as well.

[b-man]

Today was a fun day for me. My new crate LS3 showed up at about 2:30 PM and I was ready with my trusty (not rusty) '70 Chevy pickup, I had driven it to work for the last 3 days anticipating the engine delivery. The old workhorse did double duty today, picking up the new engine and dropping off the tattered Tempest front bench and back seat at the upholstery shop after work on my way home.

My prize:



Good ol' pickup, this truck equipped with a factory 402 big-block/TH400 hauled my '64 GTO back and forth to the bracket races for over a decade:



Tomorrow I'll tear the crate apart and deposit the LS3 in my garage, I'm too tired to do it tonight. More pics coming soon.

[455HOGT37]

OK... NOW I'm really motivated to drop by...

Looks like an early Christmas!

[b-man]

Pulled the top off the crate tonight and hoisted the LS3 off the pallet.



The Tempest gets acquainted with the new-tech motivating force.



Merry Christmas to me!



My upholsterer called me today, he was able to locate the original striped cloth for the seats ($79/yard) as well as the correct color vinyl. Now my seats will look as factory original as possible, I was almost sure I'd have to compromise and end up with something different.

I'm so stoked.

[78 GHOST]

Bart, that looks very cool! I know you've got headers, but is that absolutely necessary in a typical A-Body? Do you think you could have used the stockers?

Thanks in advance.

[b-man]

Originally Posted by 78 GHOST

Bart, that looks very cool! I know you've got headers, but is that absolutely necessary in a typical A-Body? Do you think you could have used the stockers?

Thanks in advance.

According to everything I've read about this particular early A-body swap, the only manifolds that would fit are F-body ones. Even then, the driver's side requires either notching the frame or cutting off one 'ear' then drilling and tapping the 3-bolt pattern on a smaller bolt circle 60 degrees from where it was originally.

If the Corvette manifolds would have fit, I would have gladly saved the $600 and used them. I figured the Edlebrock headers would be a slam-dunk and solve any exhaust problems, and the added 20 to 30 HP wouldn't be a bad thing.

[andrewb70]

Moving right along. You should have this beast running in a couple of weeks, right? :-)

Andrew

[b-man]

Originally Posted by andrewb70

Moving right along. You should have this beast running in a couple of weeks, right? :-)

Andrew

Don't I wish.

Too many worn-out things to fix on this old heap along with new non-swap related goodies to install before I get to the real 'meat' of the swap.

My weekends are too short.

Bart

[andrewb70]

Originally Posted by b-man

Don't I wish.

Too many worn-out things to fix on this old heap along with new non-swap related goodies to install before I get to the real 'meat' of the swap.

My weekends are too short.

Bart

Bart,

You may also want to consider ditching the b-body spindles and going with the ATS AFX spindles.

Andrew

[b-man]

Originally Posted by andrewb70

Bart,

You may also want to consider ditching the b-body spindles and going with the ATS AFX spindles.

Andrew

Right now I can't, my build will already be way over budget even without touching the front suspension. The interior work, some new modern floor insulation and a new windshield (old one is cracked) will have to take precendence over the front end for right now.

I do plan to upgrade the rear suspension with a set of Currie Currectrac arms during this phase of the build.

I saw the ATS spindles you set your car up with, very nice. To use them I'd also have to buy a new set of front control arms, at least a set of uppers, correct?

Bart

[quick67bird]

This looks like a fun build. I have thought about doing this with my GFs 64 Lemans, but I have bought a traditional Pontiac 455.

Robert

[b-man]

Originally Posted by quick67bird

This looks like a fun build. I have thought about doing this with my GFs 64 Lemans, but I have bought a traditional Pontiac 455.

Robert

Thanks for the kind words Robert. The Tri-Power 455 that I took out of the Tempest will live on (with better heads, cam and tri-y headers) in another one of my '64s, a Lemans convertible with factory A/C and power windows.

Now, a few more questions for you Andrew.

1) What are the wheel width and backspace measurements on your '70 GTO?

2) Will adding the rear disc brakes to the rear end add to the track width any, and if so by by how much over stock drum brakes?

3) Same type of question on the ATS front spindles and Z06 brakes, how much added track width could one expect from making those changes over the B-body spindles and 12" disc brakes?

I'm seriously considering an upgrade to 18x9" alloy wheels. I'll put the 17X8" steel wheels and dog dish caps on my '64 Lemans convertible if I decide to do the 18" wheel upgrade.

Thanks for any info you can offer.

Bart

[andrewb70]

Originally Posted by b-man

Thanks for the kind words Robert. The Tri-Power 455 that I took out of the Tempest will live on (with better heads, cam and tri-y headers) in another one of my '64s, a Lemans convertible with factory A/C and power windows.

Now, a few more questions for you Andrew.

1) What are the wheel width and backspace measurements on your '70 GTO?

2) Will adding the rear disc brakes to the rear end add to the track width any, and if so by by how much over stock drum brakes?

3) Same type of question on the ATS front spindles and Z06 brakes, how much added track width could one expect from making those changes over the B-body spindles and 12" disc brakes?

I'm seriously considering an upgrade to 18x9" alloy wheels. I'll put the 17X8" steel wheels and dog dish caps on my '64 Lemans convertible if I decide to do the 18" wheel upgrade.

Thanks for any info you can offer.

Bart

1. Rear wheels are 18x10.5, 6.5" backspacing. Front wheels are 18x8, 4.5" backspacing.

I wish I had wider front wheels. I think I can easily run 275/35/18s. Current tires are 295/40 in the rear and 255/40 in the front.

2. The only change to the rear track will be as a result of a thicker rotor vs. the drum. So 1/8" at most, per side.

3. I can't really give you a clear answer on this issue since I never had stock b-body spindles. Before I swapped to the ATS spindles I was using Bell Tech 2" dropped spindles. According to Tyler at ATS, the AFX spindles do not change the track width at all compared to stock spindles.

The C6 Z06 brakes are monstrous. The biggest issue is not the diameter of the wheel that is required, but the spoke clearance. Going with regular C5/C6 brakes will greatly expand the wheel selection. If I was doing a 64 Tempest, I would run these wheels:

http://www.vintagewheelworks.com/products/wheels/v60

I'd run a Mickey Thompson drag radial in the rear, 295/45/17 on a 17x11 wheel.

In the front I would run a 17x9 wheel, with a 245/45-17 tire of your choice in the front.

:-)

Andrew

[David Holmberg]

Bart, I hate you man...

I'd drive the 3500 miles out there to slap you around and steal that LS3, but it would be cheaper just to buy one here.

[b-man]

Budget?

What's that?

I have decided to replace the '66 3.36 posi 8.2" 10-bolt Pontiac A-body narrow rear end with a much stronger '71 -'72 3.42 posi 8.5" 10-bolt Olds/Buick A-body (tapered bearing bolt-in axle) wide rear end. The strength of the GM corporate 8.5" rear rivals that of the Chevy 12-bolt, as an added plus the tapered bearing 28-spline bolt-in axles are best for hard cornering and overall durability.

I had been hesitating to replace the early narrow 8.2" rear end with a later wide 8.5" rear end (1" wider overall, 1/2" per side) mainly because of the way my steel 17X8s were built, they won't fit in the rear with 4-1/2" of backspace and a wide rear end. Now that I have decided to go for a set of 18X9" wheels all around I can buy new wheels that will fit with a wider rear axle.

The 17X8" steelies and dog dish caps will soon find a new home on my '64 Lemans convertible.

After doing some measuring I see that I will have 7.25" from the wheel mounting surface on the rear drum to the frame rail/inner fender and 4.50" to the outer fender inner body panel, for a total of 11.75" of room from side to side for a wheel/tire assembly.

A 9" wide rim is 10" in overall width, once you add the width of the outer wheel lips to the width of the 9" bead width of the rim. With the rim perfectly centered from side to side (looking from the rear) in the wheelwell, ideally I should have .875" of body/frame clearance on both sides of it (11.75" - 10" = 1.750", divided by 2 = .875").

After doing some internet research I have found a 18X9" wheel spec'd for a 2008 BMW Z4, the 5 on 120 mm bolt pattern is plenty close enough to the GM 5 on 4.75 to work (120.65 mm). I'm not first guy to use the 120mm bolt circle BMW wheels on a GM car.

I need a 9" wheel with close to 6.5" of backspace to center the wheel from side to side, the wheels I found have a 40mm offset which is the same as 6.57" of backspace. A tad toward the inside, but still very good.

After I upgrade to rear disc brakes on the car the rear wheel will move outward by about .125", moving the wheel pretty close to the exact amount I want to center it even better. I should end up with something like .805" between the inner wheel lip and the frame/inner fender panel, pretty close to perfect.

I can use this same wheel up front with a 1.25" thick billet aluminum wheel adapter, I have room to go inward by about 1" but almost no room to go outward. Using the 1.25" adapter effectively changes the 6.57" wheel backspacing to 5.32", moving the outer face of the front wheel lip outward by about .180" (less than 3/16") from where it is right now with the current 17X8" 4.5" backspace wheels.

I will run the same size tires front and rear, 245/40-18, 25.7" tall. This size tire will have very close to a 10" section width (sidewall to sidewall) mounted on a 9" rim, it is spec'd at 9.8" when mounted on an 8.5" wide rim.

I can rotate the tires from front to back by running the same size front and rear, plus I happen to like that look. There's still plenty of room to go up in size to a 275/40-18 that's 26.6" tall in the rear later on too if I change my mind.

My wheel choice, 18X9" O.Z Racing Ultraleggera, black painted of course.

40 mm offset/6.57" backspace, weighing only 20.8 pounds.







Spent some time today while it is still unseasonably warm out to get wet and dirty cleaning up the front suspension and engine compartment a bit. The front end cleaned up pretty nice.

The frame from the firewall forward, front suspension and inner wheelwells are coated with semi-gloss black POR-15. Note the junkyard 12" B-body rotors that have been redrilled from the 5 on 5" GM big car pattern to the 5 on 4.75" GM intermediate pattern.





Moving forward.

[FLYNLOW]

http://www.motorsport-tech.com/

Ordered my wheel adapters from them. Hub centric, made in the US, very nice pieces and very reasonable prices. And you can get them made in any thickness you want to the MM to get your BS just perfect.

[b-man]

Originally Posted by FLYNLOW

http://www.motorsport-tech.com/

Ordered my wheel adapters from them. Hub centric, made in the US, very nice pieces and very reasonable prices. And you can get them made in any thickness you want to the MM to get your BS just perfect.

Thank you, this is a big help.

I was just checking out some adapters and they have 120mm listed rather than 120.65 for the 1964 GTO/Tempest bolt pattern. Looks like the slight difference between the two bolt circles (4.750"[120.65 mm] - 4.7244"[120 mm] = .02559") isn't enough to cause any problems.

EDIT:Concerning the slight bolt pattern difference I noted above, you must be careful when using the wheel adapter configuration feature on that site. It must think that the 1964 GTO (120.7 mm) that I entered is the same as a late 2004 - 2006 GTO (120 mm).

I also tried a 1972 GP and it came up with a 115 mm bolt circle which is a late model FWD GP pattern. Only by entering a 1st or 2nd-gen Firebird it came up with the correct 70.3 mm center bore and 120.7 mm (120.65 mm) bolt circle, it thinks that 1964 was a Firebird year too. Pontiac is misspelled as 'Pontaic' on there as well.

I'll probably buy a pair of 28 mm (1.1") adapters for the front, effectively giving me a 5.47" backspace wheel for the front.

The slight bolt pattern difference will be fixed up front with the adapters. In the back I'll see if I can get the axles stud holes redrilled or reamed to move the bolt circle inward slightly and install some new 12 X 1.5 mm studs.

[b-man]

I decided to buy 245/40-18s and 275/40-18s since this thing could really use some tire to help handle the 450+ HP I'm expecting. Now that my wheels and tires are on order along with my front wheel adapters (27 mm/1.06") it's time again to do some more work to prep the body.

I removed the windshield so I could put a halt to the rust that was forming in the window channel, plus it had a crack that was slowly growing downward from the rear view mirror area.



Other than a few lower windshield trim clips that were pretty much consumed by the rust I don't see any really bad spots.



Some heavy pitting is present but no holes that I can see so far, after some more work with a wire brush it will soon be ready for the POR-15 treatment. For those of you who haven't tried POR-15, you'll soon see the near miracles this stuff can perform. At only $45 a quart it's an affordable solution for minor to moderate rust problems.