Build thread: LS into 1975 Convertible
#1
Drifting
Thread Starter
Build thread: LS1 / T56 into 1975 Convertible
Well, it’s time for a new project…one I’ve been wanting to do since I owned my first Corvette (also a ’75) 5 years ago. I’ve been working on cars since I was 14 years old (21 years ago), and I’ve slowly been progressing in project difficulty. My last car was a 2001 Pontiac Trans Am WS6 that started as a Procharger car until the stock LS1 let go, and then became an N/A car with an LQ4 shortblock, LS6 heads, custom cam, etc. You may have seen my build thread on that car…if you like, you can find that build thread here…
http://ls1tech.com/forums/generation...s-debacle.html
I got the opportunity to pick my current car up in a trade for the WS6. It’s a ’75 Convertible with some custom tweaks…white and black interior, hooker sidemount headers and pipes, and a NOM…a recently built 406 with Brodix heads, Performer intake, Holley 650 DP, Howards hydraulic-roller cam, and some other small mods. The car also has a nice radiator…a Be Cool unit with the automatic trans cooler built in. Transmission is the stock th400, although it has a very recent rebuild and actually shifts very nice and firm. The car has all new brakes and brake lines, as well as some suspension mods. It also had a ton of stereo stuff installed behind the seats that I pulled out the day I got it home…lol. Overall, a very solid car that I felt like would be a perfect candidate for my project.
I’m pulling the 406/th400 and selling everything attached to it…ignition, accessories, brackets…everything. I haven’t purchased the new engine or trans, yet…the plan is to install an LS motor and a hopefully a T56 if I can swing it financially…otherwise I may ultimately go with the 4l60e or 4l80e. I’d like to find a complete pullout with harness, ecm, and all accessories out of an F-body if I can, but I’m also open to using an LQ9 or possibly an LQ4 if I can find one for the right price. At that point, I can piece the rest together.
So enough of the introductions, and onto the pics. I take a lot of pics, so some of these will be redundant. Hopefully I can help someone who might be looking to do this swap in the future…
Got the hood off and snapped a couple of final "before" shots...
The 406...
Radiator and condenser out...
Accessories off...
Much more to come. Thanks for looking.
http://ls1tech.com/forums/generation...s-debacle.html
I got the opportunity to pick my current car up in a trade for the WS6. It’s a ’75 Convertible with some custom tweaks…white and black interior, hooker sidemount headers and pipes, and a NOM…a recently built 406 with Brodix heads, Performer intake, Holley 650 DP, Howards hydraulic-roller cam, and some other small mods. The car also has a nice radiator…a Be Cool unit with the automatic trans cooler built in. Transmission is the stock th400, although it has a very recent rebuild and actually shifts very nice and firm. The car has all new brakes and brake lines, as well as some suspension mods. It also had a ton of stereo stuff installed behind the seats that I pulled out the day I got it home…lol. Overall, a very solid car that I felt like would be a perfect candidate for my project.
I’m pulling the 406/th400 and selling everything attached to it…ignition, accessories, brackets…everything. I haven’t purchased the new engine or trans, yet…the plan is to install an LS motor and a hopefully a T56 if I can swing it financially…otherwise I may ultimately go with the 4l60e or 4l80e. I’d like to find a complete pullout with harness, ecm, and all accessories out of an F-body if I can, but I’m also open to using an LQ9 or possibly an LQ4 if I can find one for the right price. At that point, I can piece the rest together.
So enough of the introductions, and onto the pics. I take a lot of pics, so some of these will be redundant. Hopefully I can help someone who might be looking to do this swap in the future…
Got the hood off and snapped a couple of final "before" shots...
The 406...
Radiator and condenser out...
Accessories off...
Much more to come. Thanks for looking.
Last edited by Quil; 01-21-2012 at 04:00 PM.
#2
Drifting
Thread Starter
Got quite a bit done today. Most everything underhood is removed or unhooked and ready to go. Tomorrow I'll crawl under the car and get the driveshaft pulled and the tranny unbolted and it should be ready to pull.
And here's a shot of the sidemount headers. They'll have to have the flanges cut off, and a set of LS flanges welded on. There will be quite a bit of custom work on these, since the primaries on a SBC and LS are in different location...the primaries on these headers will have to be spread/cut/rewelded to line up with the LS flanges. After which I'll get them cleaned up and rechromed...
And here's a shot of the sidemount headers. They'll have to have the flanges cut off, and a set of LS flanges welded on. There will be quite a bit of custom work on these, since the primaries on a SBC and LS are in different location...the primaries on these headers will have to be spread/cut/rewelded to line up with the LS flanges. After which I'll get them cleaned up and rechromed...
#3
Le Mans Master
Loks like a very nice car to start with.I converted my sidepipes and relocated the pipes to ls flanges over 5 years ago,wasnt too bad to do.Mine were black already so i just repainted high heat and wrapped them.Oh and good luck i will be following the build.
Last edited by PatsLs1vette; 12-03-2011 at 06:23 PM.
#4
Drifting
Thread Starter
Thanks Pat. I've read a lot of your posts on LS swaps, and I hope you don't mind if I pick your brain on some issues down the road. I'm going to need all the help I can get.
#7
Safety Car
Member Since: Aug 2001
Location: North Easton Mass
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You should get 3 O2 bungs welded in to the collectors also, provided you are planning to use the front O2 sensors. The 3rd bung is for the wideband O2 sensor that dyno tuners use when tuning the car.
Rick B.
Rick B.
#8
Drifting
Thread Starter
Not a lot to report from today. Got the driveshaft pulled, trans crossmember dropped, and everything unhooked from the trans (I hope). Should just be a matter of pulling the bolts on the motor mounts and yanking the engine and trans out now. Hopefully tomorrow on that...
#9
Safety Car
Member Since: Aug 2001
Location: North Easton Mass
Posts: 4,883
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Definitely. I've been eyeballing the collectors to see where is best to locate the bungs. And I already have HPTuners, so that should help considerably along the way with getting all the computer stuff set up.
Not a lot to report from today. Got the driveshaft pulled, trans crossmember dropped, and everything unhooked from the trans (I hope). Should just be a matter of pulling the bolts on the motor mounts and yanking the engine and trans out now. Hopefully tomorrow on that...
Not a lot to report from today. Got the driveshaft pulled, trans crossmember dropped, and everything unhooked from the trans (I hope). Should just be a matter of pulling the bolts on the motor mounts and yanking the engine and trans out now. Hopefully tomorrow on that...
HP Tuners is a great tool but you can also get yourself into a lot of trouble using it if you aren't a tuning expert. If there is someone in your area that has stellar reccomendations as a tuner it might be worth the $ to get the engine dialed in.
Rick B.
#10
Drifting
Thread Starter
Probably the best thing to do is wait until the engine is in the car and the headers are fitted to make the decision on the bungs. There are a lot of things that can get in the way that you won't see until everything is in place.
HP Tuners is a great tool but you can also get yourself into a lot of trouble using it if you aren't a tuning expert. If there is someone in your area that has stellar reccomendations as a tuner it might be worth the $ to get the engine dialed in.
Rick B.
HP Tuners is a great tool but you can also get yourself into a lot of trouble using it if you aren't a tuning expert. If there is someone in your area that has stellar reccomendations as a tuner it might be worth the $ to get the engine dialed in.
Rick B.
#11
Drifting
Thread Starter
Out with the old...
And here's another shot of the interior. Trying to figure out exactly which direction I want to go here, especially on the gauges. I wanted to go with some of the Speedhut guages (especially the GPS speedometer), but I think the biggest you can get for the speedo and tach are 4". I'm afraid they won't look right in the C3 housings. The 2 1/16 gauges for the center housing would fit perfect, though. Was thinking about silver faces on the guages...
Also going to do C5 seats eventually. Have to decide whether or not to have the seats recovered in white, or to change the entire interior to black. I love the two-tone white and black, but the white sure does show dirt easily...
Now to get everything cleaned up and start selling everything in sight to pay for this build...
And here's another shot of the interior. Trying to figure out exactly which direction I want to go here, especially on the gauges. I wanted to go with some of the Speedhut guages (especially the GPS speedometer), but I think the biggest you can get for the speedo and tach are 4". I'm afraid they won't look right in the C3 housings. The 2 1/16 gauges for the center housing would fit perfect, though. Was thinking about silver faces on the guages...
Also going to do C5 seats eventually. Have to decide whether or not to have the seats recovered in white, or to change the entire interior to black. I love the two-tone white and black, but the white sure does show dirt easily...
Now to get everything cleaned up and start selling everything in sight to pay for this build...
#12
Drifting
Welcome to the other side, these LS swaps get real expensive real quick, unless you just do a drop in and leave everything else alone and run the LS setup as it was from the donor car, but thats no fun and you might as well do it up, and do it right the first time around.
There are a few of us (myself and Gordonm and a few others) currently doing an LS swap. Are you prepared for the ride? Where do you stop with up grades, cleaning and replacing while you're doing the swap. This gets crazy real quick, but the end results are all worth it.
I look forward to seeing your progress.
Riggs
There are a few of us (myself and Gordonm and a few others) currently doing an LS swap. Are you prepared for the ride? Where do you stop with up grades, cleaning and replacing while you're doing the swap. This gets crazy real quick, but the end results are all worth it.
I look forward to seeing your progress.
Riggs
#13
Drifting
Thread Starter
Welcome to the other side, these LS swaps get real expensive real quick, unless you just do a drop in and leave everything else alone and run the LS setup as it was from the donor car, but thats no fun and you might as well do it up, and do it right the first time around.
There are a few of us (myself and Gordonm and a few others) currently doing an LS swap. Are you prepared for the ride? Where do you stop with up grades, cleaning and replacing while you're doing the swap. This gets crazy real quick, but the end results are all worth it.
I look forward to seeing your progress.
Riggs
There are a few of us (myself and Gordonm and a few others) currently doing an LS swap. Are you prepared for the ride? Where do you stop with up grades, cleaning and replacing while you're doing the swap. This gets crazy real quick, but the end results are all worth it.
I look forward to seeing your progress.
Riggs
For the engine and trans, I'm hoping for a complete pullout LS1/T56. I'll do a cam swap to something like a 224R or 228R, and call it good until I've gotten the car running and the bugs ironed out. If I can't swing the T56 and go with the 4l60e, then I'll definitely pick up a transgo shift kit and something like a 3200 stall. And that's really going to be it for the engine/trans for now. Unless I full ape sh@! and piece together a short block, some 243/799 heads, etc. But I'd honestly rather avoid piecing this build together.
I know the other stuff like fuel system, wiring harness, gauges, etc is going to add up fast, so I'm staying pretty conservative for now. If money looks like its going to be way too tight, I might opt for modding an LQ9. But then again, like you said, I really should just hold out and do it the way I want the first time. It's winter, and there's always the C5 to drive in the spring...
#14
Drifting
Upgrade your steering.
Quil,
I see that you have been running the stock power assisted steering set up. Now is the time to bring your steering into the twenty first century and replace all that junk with a Borgeson integral power steering box. It will be oh so simple to fit it with the engine out. If you're at all unsure, try to get a drive of someone's car whose owner has done the conversion or at least talk to guys like Randy, 682XLR8 here on the Forum. Also Solid LT1 and there are others.
Good luck with the LS conversion. I have no plans to do this to any of my cars, but who knows what the future holds? I would rather do the LS swap than "hot up" the small blocks. There are plenty of Holden Commodore engine/transmissions at wrecker's yards here in Australia, so sourcing one isn't difficult. It's just the crazy prices they're asking.
Good luck, I'll be watching your progress.
Regards from Down Under.
aussiejohn
I see that you have been running the stock power assisted steering set up. Now is the time to bring your steering into the twenty first century and replace all that junk with a Borgeson integral power steering box. It will be oh so simple to fit it with the engine out. If you're at all unsure, try to get a drive of someone's car whose owner has done the conversion or at least talk to guys like Randy, 682XLR8 here on the Forum. Also Solid LT1 and there are others.
Good luck with the LS conversion. I have no plans to do this to any of my cars, but who knows what the future holds? I would rather do the LS swap than "hot up" the small blocks. There are plenty of Holden Commodore engine/transmissions at wrecker's yards here in Australia, so sourcing one isn't difficult. It's just the crazy prices they're asking.
Good luck, I'll be watching your progress.
Regards from Down Under.
aussiejohn
#15
I did my LS1 /4L60 swap 6 years ago.It was the best thing I've done to my 73. The engine and trans came out of 2002 W S6 Ram Air Trams Am and I paid $3700 for engine,trans.ecm ,harness and all accessories.
The mileage was 27000 miles and it was clean.Sold my orginal engine with a tune port and700r for $2500 and still spent $3000 on the swap.I have put around 25000 miles with no major problems.The gas milage is 24 highway and 20 city. The engine is stockand very dependable.I thinking about selling and building a 70 or 71 t top with tube chassis and LS3. I live about 4hrs from you and if you don't have your swap done in the spring you are more than welcome to look at my swap.Good luck with your swap.Charlie
The mileage was 27000 miles and it was clean.Sold my orginal engine with a tune port and700r for $2500 and still spent $3000 on the swap.I have put around 25000 miles with no major problems.The gas milage is 24 highway and 20 city. The engine is stockand very dependable.I thinking about selling and building a 70 or 71 t top with tube chassis and LS3. I live about 4hrs from you and if you don't have your swap done in the spring you are more than welcome to look at my swap.Good luck with your swap.Charlie
#17
Race Director
Im with Riggs on this one. My budget has gone out the window long ago. I have sold off pretty much everytning and it helps but it gets out of control quickly. I gave up on budget and just decided to do it like I want. The biggets problem is finding parts and waiting for them. Then making them fit. So far pretty much everything has been custom. That is the fun part but is time consuming. Keep up the posting on your project. Always interesting to see how others are doing the swap.
#18
Drifting
This might not be what your looking for but if I had to start all over again, here is what I would install.
http://www.jegs.com/i/Blueprint-Engi...08#moreDetails
I would back this with a T56 or better. The auto transmissions would not stand up to any abuse with out rebuilding them, I would defiantly run a standard shift with a hydraulic clutch.
With the purchase of the low mileage pull out and the rebuild of the trans along with all the upgrades I have done to the LS setup I am setting at around $13 thousand + more for all the other upgrades I have done and will still need to do before this swap is considered done.
Riggs
http://www.jegs.com/i/Blueprint-Engi...08#moreDetails
I would back this with a T56 or better. The auto transmissions would not stand up to any abuse with out rebuilding them, I would defiantly run a standard shift with a hydraulic clutch.
With the purchase of the low mileage pull out and the rebuild of the trans along with all the upgrades I have done to the LS setup I am setting at around $13 thousand + more for all the other upgrades I have done and will still need to do before this swap is considered done.
Riggs
#19
Drifting
Thread Starter
Thanks for the comments guys, I appreciate it. There's a lot to consider with this swap, and my head is spinning with all the options. Luckily I have nothing but time to do it, and there's a lot of time-consuming "elbow-grease" type work to be done before I make any critical decisions anyways.
Next step is eliminating the A/C lines and removing the rest of the MSD wiring, and then cleaning and detailing the engine bay. The underside of the car is filthy...looks like there was an oil or trans leak at some point, so I'll be under there with a wire brush, rag, and a can of gunk for about a week getting all that cleaned up as well. Plenty to keep me busy as I get a garage sale of parts going.
Next step is eliminating the A/C lines and removing the rest of the MSD wiring, and then cleaning and detailing the engine bay. The underside of the car is filthy...looks like there was an oil or trans leak at some point, so I'll be under there with a wire brush, rag, and a can of gunk for about a week getting all that cleaned up as well. Plenty to keep me busy as I get a garage sale of parts going.
#20
I've had mine done for a couple yerars, very happy with it.
I bought an LQ9 because of price and that exhaust and a tune alone put it over 400hp. Keep in mind f body LS1s have not been made for 10 years. I tend to question low milage claims on those motors.
I went with a Richmond 6 speed and it's just plain fun to drive, go with a manual trans if you can.
I bought an LQ9 because of price and that exhaust and a tune alone put it over 400hp. Keep in mind f body LS1s have not been made for 10 years. I tend to question low milage claims on those motors.
I went with a Richmond 6 speed and it's just plain fun to drive, go with a manual trans if you can.