LT1 powered FB
 

I wanted to make this thread to chronicle my build and also provide info for V8 swaps in FBs, particularly LT1, this motor has lots of nuances that are not well detailed on the net.

I had originally bought this car with no intentions of swapping, but stumbled into an awesome deal on the motor and trans.

I have an 85 GSL, originally an auto and am putting an LT1 from a 94 caprice and T5 NWC in it. I probably will either build the T5 or go with a T56 eventually.

This is a rough list of the things I have done so far
-Granny's SBC swap kit
-Custom transmission crossmember
-5 lug turbo II hub and brake swap
-Custom front chassis spreader bar w/radiator mounts
-Granny's Radiator
-Steel wheels 15"x7" agressive offset
-AP Racing clutch MC
-Installed clutch pedal
-LT1 wiring harness modification
-Rear battery mounting in storage bin
-battery cut off switch
-VATS disable for LT1
-Rams horn exhaust manifolds
-Moved motor mounts back 1.5"
-Modified mustang short throw T5 shifter
-Speedo cable block off
-Bronze shifter bushing


To Do
-Exhaust system-side exit
-Air intake
-Custom gauges
-Relocate PCM for LT1
-finish energy suspension bushing install
-lower car with custom lowering spring and adjustable spring perch
-short stroke shocks
-Racing seat and harness install

This is the car while I was pulling the rotary
https://cimg2.ibsrv.net/gimg/www.rx7...e2e5d2a626.jpg

https://cimg6.ibsrv.net/gimg/www.rx7...26f1c20ed0.jpg

I modified the oil pan to clear the steering link, rather easy to do and cheaper than buying a new one
https://cimg2.ibsrv.net/gimg/www.rx7...debbeb5f3c.jpg

I had a later style T5 so I made an adapter plate to go from a chevy to ford pattern. I do not see an issue yet.
https://cimg1.ibsrv.net/gimg/www.rx7...6898bb06ec.jpg


https://cimg9.ibsrv.net/gimg/www.rx7...87c8ab43cf.jpg

I installed an AP racing master cylinder with the stock chevy slave cylinder
https://cimg1.ibsrv.net/gimg/www.rx7...15501a669d.jpg

I decided to move the engine back by about 1.5" Before the harmonic balancer was contacting the front sway bar. To do this I drilled two holes in the FB crossmember and then moved the engine. The motor is now right up against the firewall. This also provides more space to route the radiator hoses
https://cimg2.ibsrv.net/gimg/www.rx7...40da3e9e12.jpg

This is the custom transmission crossmember. The automatic FBs have their transmission crossmember mounts in a different position than the manual cars
https://cimg3.ibsrv.net/gimg/www.rx7...a123d10c57.jpg

What is hitting the firewall? The motor or the distributor? Also what helped to you decide to go this route? Is the rotary bad? Good stuff, keep the updates coming. :)

The motor itself is actually extremely close not quite hitting the firewall, no distributor on LT1, they use the optispark which is behind the water pump

Hey Freeskier thanks for posting your build. In the beginning I had contemplated an LT1 but just seemed like it was going to cost a little more to buy and modify. Plus I had always liked the 5.0 and fox body mustangs. I look forward to seeing future posts and hearing it run. Good luck

I got a super good deal on the LT1 which made the choice easy, Otherwise I probably would have stayed rotary. Looks like your build is coming along good as well.

I put my mounts in this weekend and found out I need to shorten the driveshaft a bit, gonna get that done this week. I also started replacing my bushings with the new energy suspension poly ones I bought

What are you guys having to do for the front suspension?

For the weight change? I am doing a coilover setup like the respeed or ground control kit with short stroke MR2 dampers so I can go super low

But not super slow!

Is the turbo ii front hub/brake swap difficult? Any chassis modifications to accept? Does the original steering knuckle/spindle get reused or the turbo ii knuckle/spindle?

Any chance you would mind posting some rough measurements of that oil pan you cut down? Did that give plenty of clearance?

Sorry for the late response, had a sick kid and wife last week, now the family is better :)

It is not super difficult but requires some machined parts and custom brake caliper brackets. No chassis mods are required. I have also seen that you could swap the ball joint with an AE86 unit on the LCA and use the Turbo II spindle, but I never tried. I do have the files for those parts that need to be made.

I will try to get some measurements and pictures tonight. Since I moved the motor back I still have plenty of clearance. I also had to cut down the windage tray and some of the main cap bolts, but that was not a big deal.

Update pics, got my driveshaft on and almost finished the radiator hoses. I am also thinking about making custom boxed sheetmetal lower control arms

https://cimg2.ibsrv.net/gimg/www.rx7...44f8672384.jpg


https://cimg8.ibsrv.net/gimg/www.rx7...b84dbe848f.jpg


https://cimg9.ibsrv.net/gimg/www.rx7...27b6585656.jpg


https://cimg0.ibsrv.net/gimg/www.rx7...0134d8dea7.jpg

What are you doing for fuel lines? Are you running coolant to the heater core?

Looking good! That thing is sweet.

I am reusing the stock hard lines, I mounted a walbro fuel pump in the tank. There are rubber hoses from the fuel lines to the rail. Right now I do not have the heater core hooked up, but I may try to make some lines for that.

Thanks :cool:

I got this trick piece for my coolant head bleed. Tackling power steering this week, converting to AN PTFE lined hose.


https://cimg5.ibsrv.net/gimg/www.rx7...a00ee23d24.jpg

got it running...

https://vimeo.com/154451129

Nice work!

Any chance you could post a link or part number for the coupling you are using for the head bleed?

Hell yeah! So exciting man. Thanks for the video it keeps me movitivated to make the time for my project. I love it.

Question. Is the ECU water resistant? I have to figure a way out to get my inside the cabin and the ECM connector is a little big for a standard hole.

looking good! Can't wait to see ya run it.

IT is from JTR Stealth Conversions V8 Cooling System Parts - LS1 Steam Vent Tee

Mine is, stock caprice actually have the ECU in the engine bay. You will have to depin unfortunately. I contemplated that but I am going to be making a new harness instead to move the computer inside

I think the smartest thing you did was getting a 94 Caprice engine. I got the 95 and found out that the 94-95's have the $EE PCMs which are the only OBD1 ones that have eeprom. It means to flash the pcm you DON'T NEED A ROM BURNER. you only need and ALDL interface and you can then use TunerPro and CATS winflash. way waaaay cheaper than an OBD2 system. TunerPro is free, winflash is like $20, and you can make a $5 ALDL interface out of a FT232RL board like this

It was dumb luck lol. Thanks for the link, I will definitely be building that. My friend had this engine lying around as a spare for his LT1 powered blazer. I also found out that my opti is the vented version as well (only after I threw away the vent harness by mistake)

any updates? Is this thing on the road?

I was able to move it out of my garage under its own power, I need to get an exhaust before I can drive it any distance. Mostly cleaning things up now, I will post some pictures once I get my new racing seat and stuff.

Hey Freeskier. I had a few questions about how you set up your fuel system.

Did you use the stock hard lines to feed fuel to the engine?

Is so do you now if the fuel line size is the same as the SA?

He stock hard lines on the SA seem to be shy of a 1/4". Just want to make sure I don't run lean under high load situations. Using the fuel lines would make things a lot easier on me how ever.

The fuel pump is another thing I am trying to figure out right now. The SA have an external inline pump. I would like to find a way to in cooperate an in the tank pump. I found a couple in tank guys. One is expensive but the other may require a hole larger than I can fit.

https://cimg6.ibsrv.net/gimg/www.rx7...6a9422d32.jpeg


https://cimg1.ibsrv.net/gimg/www.rx7...6ab6d6dae.jpeg

Hey man,

I have used the stock fuel hard lines for now, I believe all 12A cars had similar sized fuel line. I will let you know if I have any issues regarding a lean condition under high load. I bought a walbro 255 lph fuel pump and modified the stock fuel pick up to attach it. I need to add a support piece to hold the pump in better so it doesn't fall off when cornering/drifting but I have not done so yet. If I take my tank apart this weekend I will take pictures.

Test Driving

https://cimg6.ibsrv.net/gimg/www.rx7...2b1c3df3fd.jpg

Some updates.....

Had to remove the cruise control throttle position sensor so I could achieve full throttle :lol:

Car had been running ok, but would randomly start backfiring real bad, I found that my plug wires were not routed adequately so I replaced almost all of them. I found 3 or 4 that were burned bad.

After that the car ran 300% better, pulls super hard now. I was honestly underwhelmed by the power but I must have been running on 5 or 6 cylinders :scratch:

Last time I drove the car it would not start after a gas station stop and then was backfiring/breaking up really bad. I barely limped it home, but it started fine after sitting for a few hours. Checked out the coil and decided to replace it. I also spaced the coil and ICM off the head so they will stay cooler. I replaced the plugs and am checking for any other exhaust leaks. I hope to test drive this weekend again.

I suck at taking pictures, I should really try to take some good ones this weekend

Pictures of my brake conversion for Yolo7 and GFrench


https://cimg6.ibsrv.net/gimg/www.rx7...40da3d2251.jpg

https://cimg7.ibsrv.net/gimg/www.rx7...bdd3383e86.jpg

https://cimg9.ibsrv.net/gimg/www.rx7...f6382cd624.jpg

Have you replaced the optispark unit on that engine yet? The earlier versions of those things weren't vented and they get all wonky if they got wet. Before I changed mine out I was seeing similar problems. I experienced the same issues you did with the plug wires too, I had to custom make a loom that would work for the headers I had.

I have not yet, I actually have the vented version since my engine is from the B/D body cars. I am praying that it is not the optispark, but If I continue to have issues I will go ahead and change it. I am thinking that it was the coil or ICM since it wouldn't want to start for me.

Some better pictures
https://cimg5.ibsrv.net/gimg/www.rx7...3fc253bc76.jpg

https://cimg6.ibsrv.net/gimg/www.rx7...9314acfab5.jpg

https://cimg7.ibsrv.net/gimg/www.rx7...e3cd636f02.jpg

andrew man i love how you ride sits
great job
thank for the the brake pictures

gordie

Thanks, I am working on getting the suspension set up properly, right now it is on cut springs.

https://cimg8.ibsrv.net/gimg/www.rx7...a5820d3b9d.jpg

https://cimg7.ibsrv.net/gimg/www.rx7...c6a06232fb.jpg
Small update:

Putting proper suspension on, I am getting 350 lb springs for the rear (Nascar takeoffs, 5.5" x 9.75") and 450 lb springs for the front. I also ordered a coilover kit for the front as well.

Taking the front struts off and apart I discovered I still have the stock struts, I am going to put really heavy oil in them and see how they do.


https://cimg6.ibsrv.net/gimg/www.rx7...b99758616d.jpg

Hey Andrew, any updates on this car? Your car is kind of motivation for me to get mine going with a bit more effort!

Thanks for the post, car runs good, but I have a starter issue when it is hot. I am redoing the battery wiring, but I think it is the starter itself. Don't give up on your project!!

I think I might have blown a head gasket...drained the oil and it looked ok though. If I pull the motor I am going to do some head work and cam

What makes you think you have a head gasket problem?

loss of power and overheated within 5 minutes of driving.

Does it even overheat in five minutes of a cold start? That is pretty fast for any cooling system issues. Is your guage accurate or have a thermostat problem maybe? If you have a head gasket issue there are several ways to check. An easy one would be to buy a block testing kit from the parts store and check for combinations gasses in the coolant. There should also be a measurable loss of coolant if they are leaking.

It will start fine and idle fine but as soon as I put load to it, it overheats. I heard lots of gurgling as well after it overheated. I do not have a gauge on it. I should probably try the block test kit because I was able to pressurize the cooling system to 16 lbs. I need to pull my thermostat

Looks great!

Thanks, it looks better when its driving!

I ended up testing my thermostat but it was fine, so I started stripping the motor so I can pull it soon. I am going to clean up the engine bay, paint it, and do a wire tuck.

Did you ever figure out what your overheating problem was? Do you have any photos of the wire tuck?

nice work. I especially like that tranny conversion plate! :nod:

I went to put my tranny in and saw that fork going into the header and was like WTF granny said it would fit. LOL

subscribed.

Nice work.

Over a year later, what's the status?

I'm sorry. This photo just screams bad-ass! Only thing missing are drag slicks out back. :)

Do you have any photos of your exhaust setup? I'd be really interested in seeing the routing.

hey andrew
i have looked and used your picture of your bad ass ride as motovation when i needed it. last night i noticed for the first time a 5 lug front hub.
i looked back at the start of your post an see you mentioned turbo 2 front conversion
did some poking around to find it to be a 86 rx7 is that right?
also where to find these hubs ?
i searched every where and called napa
no one lists these
thanks for your thoughts
gordie

Hey Gordie,

I found the hubs and brakes off a car from Craigslist that was local. They do not make the hubs anymore unfortunately so you have to find in a junkyard or on eBay, or partout car. 86-91 should have them.