1970 Pontiac LeMans "The Bomb" Build Thread

[Way2qwk4u]

Going to start a build thread here on my 70 LeMans. Have one over on another forum. Seems more fitting over here with the direction I am taking the car. I have completed a lot of the work already. So some of this thread will be past tense. Car was my dads car back in college. Inherited it from him on a trade for a Polaris 500. He hunts more than I do and he was going to get more use out of the four wheeler and the car was just sitting. So easy decision for me. Took the car home and got started with working on it. Started life out a little rough. But she came around. I will post updates to the thread a little at a time. Have life going on like everyone else. Hope yall enjoy. Thanks

[Way2qwk4u]

Car was sent down to a friend that my dad knew and he worked it over. Got new interior and new vinyl top. New paint job. Put back together and we got it back home. Dad held onto it for a bit til we made the trade and I took it home. Looks a lot better now that she is cleaned up. Picked it up from my dads and made it about 4 miles and ran out of gas. Found out the hard way that the gauge was broken. Got it home and found milky fluid coming from the radiator cap. Kind of pink colored. Diagnosed bad trans cooler. Had to replace the radiator and flush the trans fluid and change the filter. Got that sorted and started tooling her around town. Man did she float around. Also the drum brakes were terrible. Sometimes you would stop, sometimes not, and sometimes pull you in a ditch. So after driving like that for a while I started ordering parts. And of course once you start its hard to stop.

[Way2qwk4u]

Got the first batch of parts in. New intake and carb. The old Q jet was leaking fuel. Installed new intake and carb. Removed and installed new HEI distributor and got rid of the old points. Installed a MSD digital 6AL box. New wires plugs etc. Also found a reason for the floating around. Looks like car was still rocking the original spiral shocks in the back and fronts were clearly shot. Got to look at the drum brakes and they were all out of adjustment and leaking wheel cylinders. So of course had to new brake setup. Ordered a new 4 wheel disc setup. Also had noticed that the tires on the car are older than I was at the time. So had to start figuring that out as well. Sorry about pics old potato phone pics.

[andrewb70]

Good looking car! Looking forward to more updates.

Andrew

[David Sloan]

Nice solid car to start out with!
In for updates!

[Way2qwk4u]

Got the brake kit installed. New calipers, brackets emergency cables, prop valve. Also new stainless lines and flex lines. Installed new master cylinder and booster. Ran into an issue with rear wheels. Calipers Cleared the front just fine. But the rear set would not let me install the rear wheels without contact with the caliper. So for the time being I ordered a set of steel wheels from Summit just so the car could be driven. With the new brakes and shocks the car drove much better. Not quite as nice as I was hoping but at least passable as a daily. Started making my excel spread sheet for what I wanted to do with the car and set my budget up. Had to start thinking of trying to stay original or to go more aggressive. Since I want to make this a driver and its not a GTO and is not numbers matching, I decided to not worry about originality. I wont be doing any sheet metal changes but everything else is on the table. At this point I had not decided on staying with Pontiac power or going a different direction.

[Way2qwk4u]

Drove the car at night ONCE and decided that the original T3 headlights are junk. Upgraded to HID and LED lights. Changed the woodgrain over to carbon fiber inlays. Removed the old wally world special radio. Dash was already mutilated for that install. Installed a new Kenwood Excelon head unit and added new kick panel speakers and new 6x9 deck speakers. Pulled the dash and installed a new harness. Installed a repo hood tach. Got back to driving and enjoying on the weekends. Acceleration is terrible from a stop. checked the code on the rear axle. No wonder she is running 2.73 rear gears. Has pretty good top end but gutless down low. Adding that to the list of changes.

[Way2qwk4u]

So as usual life gets in the way. Building a new house, kids and my companies growth kept me from doing a lot with the car for a couple years. I did get a couple of big things accomplished during that time but unfortunately could not find the SD card with the photos. But I did get the car a new suspension. Ordered a UMI stage 3 kit. Changed all the front suspension. Changed the shocks to ridetech HQ adjustable. Installed the lowering springs and sway bars. Changed the rear end rubber bushings to poly. Changed the rear gear set to 3.73 and added a limited slip rear differential. Also swapped the dash over to a Dakota Digital VHX setup. Installed a keyless entry and start kit. Now the car is like most newer cars. Just have to have the fob with me and I can get in and start the car without any keys. Got my self a lift for the temporary garage. Which my son thinks is awesome. So now that I have the time to get after the project I really started to think about what my next steps were. Did the math on the different power train combinations and one thing was clear. For the money there is only one choice for me at this time to check all of my boxes. I am sure you guys know what motor family I decided to go with for now. Started gathering parts for the transformation about 2019 and really got after it hard this winter. I did not want the car un able to drive. So I did not get started until everything was here.

[ryeguy2006a]

Great platform to build on. Curious to see what motor you went with. I'm sure it's not a Poncho haha.

[Way2qwk4u]

First thing in 2020 that I did was got her a new pair of shoes. I like these a lot more. Plus with the better tires the turn in and handling is way better. And the braking performance is soooo much better. I feel that I am getting full use of the upgraded brakes that were already installed. Took the old girl out on a date to the local drive through, brought my wife too . Then took it down to local shop to get a base line dyno on the old motor. Made more than I thought to the wheels. Was actually quite happy with that. The motor and trans were rebuilt before I was born and I'd say they only had about 40k on the pair. Was a little worried with how the power fell off at the top end but after the pull I remembered that I had set the MSD to 5200 so that my heavy foot would not hurt the old motor. But she is still shy of the power that I am looking for. Would love to be up around 750 tire but would be happy, I think for a while at least around 600. I want enough to be quick around town. Most of the roads around me are curving hills and 2 lane back roads. Not looking to go 9s in 1/4 mile, but to have fun carving up the back roads and maybe an autocross or road course from time to time.

[Way2qwk4u]

Got tired of the sticky , thin, huge old stock wheel. Installed a new MOMO wheel and quick release. Much nicer to hold onto and easier for a bigger guy to get out of the car. Especially with no tilt wheel. And as I would find out later makes getting under the dash etc. a lot easier. Well at the risk of being "me too". I decided to go LS. My company has a fleet if express vans and I have first dibs on any wrecks or fleet retirees. Plus I already had a iron block 5.3 that I had built for a friend who never paid for labor. So that helped make it an easy choice. I also was able to secure through, one of our installers wrecking a van, a low mileage less than 15k mile 4L80E brand new GM replacement transmission. Also some if the latest van purchases have came with the 6.0. So the course was set. LS motor and 4L80E trans. Time to order parts.



Got the trans from the wreck with a bonus engine attached. $500.00 for the insurance buy out. Also got the headers in, the mount kit, and the fuel system, oil cooler and AN fittings.


Also wanted to get the audio system done up a little better. Everything I have had before has always had maybe a head unit upgrade and or large sub box and thats all. This time I wanted to try to do a better job on this aspect. So I ordered Alpine amps one for subs and one for door speakers. Ordered a audio cap and built my first amp rack. Subs are behind the rack. 2 12" pioneers. Sounds way better than other systems I've had in the past. Still need to build out the trunk floor and side panels.


Also started figuring out the wiring for the LS. Was looking at just running the stock van ECU and using HP Tuners. But after spending the time setting up the harness and then adding up the credits and the hardware I decided to go a different route. Terminator X Max for now. I really like the software, found it easier to work with and more what I was used to. Plus later if I need to go to the dominator most of the harness can stay the same.

[GarageToys]

Sweet build so far. Perfect wheel choice by the way.

[Way2qwk4u]

Thanks. It was an easy choice. There were a few other options that I had considered but I did not want to sell the house to be able to buy one wheel.


Getting another spare trans and another motor. Free on this one



New ARP hardware, Summit Pro LS cam, new converter, billet 710 cap, and more plumbing materials.




One of the last drives before pulling old engine.


Test fitting the swap pan on the new motor. Pan is supposed to be for A-body swaps. Has -10 oil line connections and is baffled.

[andrewb70]

If I can help with the Holley EFI tuning, let me know.

Which Summit cam did you go with?

Andrew

[Way2qwk4u]

If I can help with the Holley EFI tuning, let me know.

Which Summit cam did you go with?

Andrew

Thanks, Went with the summit stage 4 auto pro LS cam. Got matching stall converter. I might need a hand on tuning when I get it one the road. Right now I have the cold start and idle tuning done. Correction on the learn is down to less than 2% in the idle area. I went ahead and lowered the allowable correction % down to 10%. Left the upper cells alone til I can actually drive it. Snow is too deep and then there is the road salt. Might also have some trans tuning questions. Working on installing a trans line pressure transducer here soon so I can log line pressure. This winter 2021 or next spring the plan is to go LSA charger.

[Way2qwk4u]

Gave the new engine a coat of Pontiac blue. At least the color will still be correct.





Pulled the heads off. Installed the new matching spring pack and new valve seals. Installed new lifters and trays. Reused push rods and stock rockers for now. Will probably replace the rockers soon. Lift on the new cam is .625 so not sure about not having a roller tip rocker. New OEM bolts for this round. Going to reuse the truck intake for now. Installed the heads and new head gaskets. Mocked up the headers and the coils and wires. Pre wired the motor to figure out the wiring harness routing. Painted the new water pump and brackets. Verified cam specs and degreed in the cam. Checked oil pump tolerances. Primed with oil and verified rotation and valve clearance.




Got the Terminator X wired in on the test bench. And could not help it, had to hear it run. So I stand started it to verify oil pressure and that it at least ran. Id hate to drop it in and then fight an issue that I coulda found first.

[andrewb70]

Thanks, Went with the summit stage 4 auto pro LS cam. Got matching stall converter. I might need a hand on tuning when I get it one the road. Right now I have the cold start and idle tuning done. Correction on the learn is down to less than 2% in the idle area. I went ahead and lowered the allowable correction % down to 10%. Left the upper cells alone til I can actually drive it. Snow is too deep and then there is the road salt. Might also have some trans tuning questions. Working on installing a trans line pressure transducer here soon so I can log line pressure. This winter 2021 or next spring the plan is to go LSA charger.

There is no reason to reduce the CL or the Learn limits until you have the whole VE table sorted out.

Andrew

[ryeguy2006a]

Lots of progress, Nicely done! One suggestion is to upgrade your pushrods now. With the higher lift of that cam, you'll likely bend them. LS pushrods are a major weak link.

[Way2qwk4u]

There is no reason to reduce the CL or the Learn limits until you have the whole VE table sorted out.

Andrew

Andrew,

What about failure of the wideband? Would not think Id want it going pig rich and not running to get back home. I only changed the limits in the idle area not up in cruise or wot area. But of course that is easily changed. Im sure I will need pointers as I get to that point. If only I knew someone with more experience

[Way2qwk4u]

Lots of progress, Nicely done! One suggestion is to upgrade your pushrods now. With the higher lift of that cam, you'll likely bend them. LS pushrods are a major weak link.

Yeah upgraded valve train I feel is in the future. Probably be in the next month or so. Any running I have been doing has been below 4k rpm. I set the limiter to 5k on purpose for now. The heads were never milled and deck is stock. So I should be able to get stock push rods. Kind of wanted to get the new rockers and verify push rod length with them.