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Old 07-11-2017, 04:06 PM   #1
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Default LS3 T56 in 1978 Firebird Restomod Questions

So, I have been trolling the boards looking for info and have done a couple of LS swaps in the past. I am looking to start acquiring parts to drop and LS3 with T56 into a 1978 Firebird. I have never owned or worked on a 2nd gen fbody so I am looking forward to this project. This car is going to be almost entirely used for street use so please keep that in mind. Here are the questions I still have before getting into this project....

1. I am looking at 2 swap kits BRP and Holley. Does anyone have any experience with these especially with the T56? Do I need to do major surgery on the trans tunnel with either?

2. Drive shaft, does anyone make one for this swap or will this be a modification of the stock one? Will the stock one hold up to about 500 hp&tq?

3. What clutch slave and mounting bracket setup are people using with good streetable results?

4. AC, are people making this work with the stock parts and custom lines or is vintage air setup the way to go? Vintage air seems pricey especially if you have a factory ac car to begin with, but can make room in the budget if necessary.

5. Looking at ridetech 4kink setup. Does anyone that has this have an opinion on it? Does anyone know of a cheaper coilover setup for these cars that is a similar setup/quality?

Any help is appreciated, help with pictures is greatly appreciated. If there are any other big challenges that people have run into with this swap you think would be beneficial I am all ears.
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Old 07-12-2017, 12:54 PM   #2
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Well, it looks like I might have found a pretty good solution for one of my questions. It looks like detroit speed makes a booster/clutch master bracket. I think should work nicely for the conversion. Has anyone else run one of these for their swap?
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Old 07-12-2017, 01:51 PM   #3
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1. I am looking at 2 swap kits BRP and Holley. Does anyone have any experience with these especially with the T56? Do I need to do major surgery on the trans tunnel with either?

These kits were cutting edge 7 years ago, but they are now pricey for what you get. Dirty dingo and ebay swap plates all do the same stuff now....
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Old 07-12-2017, 03:59 PM   #4
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Quote:
Originally Posted by rcarson View Post
1. I am looking at 2 swap kits BRP and Holley. Does anyone have any experience with these especially with the T56? Do I need to do major surgery on the trans tunnel with either?
After much experimentation and building of my own stuff, I eventually landed on using the Holley trans cross member. Holley provides A LOT of technical assistance on this forum, and the part in general was very well designed. It worked seamlessly with my home-engineered swap. Toddoky (member here) has the patience of a saint.

You will need to perform a bit of surgery on your tunnel. In my case, I cut into the cross-brace in the floor just behind the shifter hole about an inch and a half, and welded in plates to box off the void between the floor and brace. My car was originally an automatic car, and I had to massage the tunnel a bit with a BFH, and then added a 4-speed shifter hump (Year One, part # F45H).

For exhaust, I'm using Edelbrock headers (no longer produced - use Holley/Hooker conversion headers) tied to a 3" Pyoes X-pipe dual exhaust with hi-flow metal core cats and el-cheapo Summit mufflers.

Quote:
Originally Posted by rcarson View Post
2. Drive shaft, does anyone make one for this swap or will this be a modification of the stock one? Will the stock one hold up to about 500 hp&tq?
There are several makers of custom drive shafts. I had an aluminum one made by Action Machine, in South Bend IN. It was $375 delivered, 4 years ago.

Quote:
Originally Posted by rcarson View Post
3. What clutch slave and mounting bracket setup are people using with good streetable results?
I started out using the DSE plate with a RAM Master, but the angle of the master to the pedal was nearly 45 degrees (should be as close to 90 as possible) and caused enough side-load on the plunger shaft to produce a noticeable leak after just 2 days of use.

I then switched to the design noted in my build thread (post #1). That too was less than ideal, having an angle around 75 degrees. Leakage occurred after a summer of very hard use. For my current setup, I did relatively major surgery on the firewall:
  • Removed the e-brake entirely
  • cut the firewall hole for the wiring harness/fuse block so I could relocate the block almost 2" to the left, as you are sitting in the car.
  • created a combination mounting plate/firewall patch that put the clutch master up at the same level as the brake master AND provided something for the fuse block to bolt to.
This approach has lasted two race seasons so far. The clutch master is right at 90 degrees.

Quote:
Originally Posted by rcarson View Post
4. AC, are people making this work with the stock parts and custom lines or is vintage air setup the way to go? Vintage air seems pricey especially if you have a factory ac car to begin with, but can make room in the budget if necessary.
sorry, no AC for me. The car is pretty much dedicated to track / autocross.

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Originally Posted by rcarson View Post
5. Looking at ridetech 4kink setup. Does anyone that has this have an opinion on it? Does anyone know of a cheaper coilover setup for these cars that is a similar setup/quality?
I kept the solid rear axle and stock-ish suspension, with some changes:
  • Moser makes housing ends and axles that allow you to convert over to a Ford-style bolt in axle setup while retaining stock brake mounting. if you do any appreciable amount of high-G cornering, you will appreciate the lack of pad knock-back that results from this.
  • stock 1998-2002 f-body rear brakes. The original 2nd gen disc brakes absolutely suck on the track.
  • True Trac diff with 3.42 gears. Works good. Kinda up in the air on longevity. I replaced a diff after one year, but the new one has held up well
  • Hypercoils makes fiberglass leafs, which knocks down unsprung weight AND eliminates spring sag. They don't make "lowering" springs though, and I had to use lowering blocks.
  • I also use a Fays2 Watts Link and axle pad locators from Custom Works Performance. Note that you will have exhaust clearance issues with the watts link. I have turndowns just before the rear axle.
  • The front cross bolts for the leafs were relocated upward 3/4 inch by drilling new holes in the spring brackets.
  • Viking DA shocks
  • removed the rear sway bar.
The car does the "Carousel" at Road America at over 100 MPH with this set up.

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Originally Posted by rcarson View Post
Any help is appreciated, help with pictures is greatly appreciated. If there are any other big challenges that people have run into with this swap you think would be beneficial I am all ears.
any time. That's what this forum is for. I'm sure lots of others will provide insight as well.

Last edited by 1981TA; 07-12-2017 at 04:13 PM.
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Old 07-13-2017, 07:34 AM   #5
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Quote:
Originally Posted by Suncc49 View Post
1. I am looking at 2 swap kits BRP and Holley. Does anyone have any experience with these especially with the T56? Do I need to do major surgery on the trans tunnel with either?

These kits were cutting edge 7 years ago, but they are now pricey for what you get. Dirty dingo and ebay swap plates all do the same stuff now....
I agree they are not cheap kits, but seeing as they come powder coated, with a trans brace, and will save me a couple of hours of work I think in all spending a little money here is worth it in my case. I have used Dingo mounts in the past and the are definitely a quality product, but again for this swap I am looking for a clean uniform look and with two young girls anything that can save me a little time is worth a few extra bucks.

Quote:
Originally Posted by 1981TA View Post
After much experimentation and building of my own stuff, I eventually landed on using the Holley trans cross member. Holley provides A LOT of technical assistance on this forum, and the part in general was very well designed. It worked seamlessly with my home-engineered swap. Toddoky (member here) has the patience of a saint.

You will need to perform a bit of surgery on your tunnel. In my case, I cut into the cross-brace in the floor just behind the shifter hole about an inch and a half, and welded in plates to box off the void between the floor and brace. My car was originally an automatic car, and I had to massage the tunnel a bit with a BFH, and then added a 4-speed shifter hump (Year One, part # F45H).

For exhaust, I'm using Edelbrock headers (no longer produced - use Holley/Hooker conversion headers) tied to a 3" Pyoes X-pipe dual exhaust with hi-flow metal core cats and el-cheapo Summit mufflers.[\Quote]

Good to know about the support provided. I feel it is rare anymore that the people selling the stuff know much more than some of the people buying it. I am going to try to run some stock exhaust manifolds on this thing. I have about 4 sets here already and since they should be good for the HP needs I am looking to achieve I may try to save a few bucks here.

Do you remember what size mufflers you are using by chance?


Quote:
There are several makers of custom drive shafts. I had an aluminum one made by Action Machine, in South Bend IN. It was $375 delivered, 4 years ago.
I kind of figured this but was hoping that one of the swap companies might have something on the shelf so I could just have it ready to go versus measure order and wait.

[Quote}
I started out using the DSE plate with a RAM Master, but the angle of the master to the pedal was nearly 45 degrees (should be as close to 90 as possible) and caused enough side-load on the plunger shaft to produce a noticeable leak after just 2 days of use.

I then switched to the design noted in my build thread (post #1). That too was less than ideal, having an angle around 75 degrees. Leakage occurred after a summer of very hard use. For my current setup, I did relatively major surgery on the firewall:
  • Removed the e-brake entirely
  • cut the firewall hole for the wiring harness/fuse block so I could relocate the block almost 2" to the left, as you are sitting in the car.
  • created a combination mounting plate/firewall patch that put the clutch master up at the same level as the brake master AND provided something for the fuse block to bolt to.
This approach has lasted two race seasons so far. The clutch master is right at 90 degrees.
Wow, that is a bummer about the DSE mount. I would have thought that the whole point of building the adapter would be to achieve the correct position/angle to the pedal. Do you think you could achieve the same angle and position with a custom bracket versus surgery?

Quote:
I kept the solid rear axle and stock-ish suspension, with some changes:
  • Moser makes housing ends and axles that allow you to convert over to a Ford-style bolt in axle setup while retaining stock brake mounting. if you do any appreciable amount of high-G cornering, you will appreciate the lack of pad knock-back that results from this.
  • stock 1998-2002 f-body rear brakes. The original 2nd gen disc brakes absolutely suck on the track.
  • True Trac diff with 3.42 gears. Works good. Kinda up in the air on longevity. I replaced a diff after one year, but the new one has held up well
  • Hypercoils makes fiberglass leafs, which knocks down unsprung weight AND eliminates spring sag. They don't make "lowering" springs though, and I had to use lowering blocks.
  • I also use a Fays2 Watts Link and axle pad locators from Custom Works Performance. Note that you will have exhaust clearance issues with the watts link. I have turndowns just before the rear axle.
  • The front cross bolts for the leafs were relocated upward 3/4 inch by drilling new holes in the spring brackets.
  • Viking DA shocks
  • removed the rear sway bar.
The car does the "Carousel" at Road America at over 100 MPH with this set up.
Sounds like you have an pretty nice setup all around for your purpose. I am looking for more of a street car that can handle some spirited driving once in awhile, but you have given me some good ideas to look at for my car.

Quote:
any time. That's what this forum is for. I'm sure lots of others will provide insight as well.
Thanks again, I am going to check out your build thread. Hopefully it is not one that got ruined by the photo bucket update. So frustrating that so many good build threads seem to have the picture portion of the post ruined by some update. I can't wait to hear more from others. Despite my low post numbers I probably have 400 or so PMs on these boards and have gotten much help from members in the past.
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Old 07-13-2017, 10:54 AM   #6
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Quote:
Originally Posted by rcarson View Post
Wow, that is a bummer about the DSE mount. I would have thought that the whole point of building the adapter would be to achieve the correct position/angle to the pedal. Do you think you could achieve the same angle and position with a custom bracket versus surgery?
I think it is possible. If you don't mind the clutch master not being in direct contact with the firewall, I imagine that a bracket could be fabricated in such a way that the bracket would fit around the brake master mounting area, and provide a place for the clutch master roughly two inch away from the firewall. The pedal would be connected to the clutch master via an extended pushrod, which would go through a hole drilled in the firewall.

Another, less complicated approach may be to use a clutch master with the mounting holes to the sides, rather than top and bottom (like the one depicted in the picture below). This would move the pushrod up and to the right, putting it at the same level as the brake master. Please note: I have manual brakes / no booster. The picture shows my "Plan A" approach from a couple years ago. I'll try to get pics of my current "Plan B" setup tonight.

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Old 07-13-2017, 07:33 PM   #7
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I am definitely interested in seeing the setup you have gone to. I may just fab up a bracket to mount behind the booster and then locate the clutch master. Then if needed make some sort of stand off and use a remote reservoir.
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Old 07-15-2017, 08:33 AM   #8
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So a couple new questions have popped up. Currently the car has an open rear with either 2.43 or 2.73 gears. It definitely needs an upgrade to some sort of posi/truetrac but I was wondering what ratio works best with these swaps and the 6speed?

Also i am looking at the year one 17" snowflakes. Can I do a 17x9 front with 17x10 rear under the stock body? I am looking to run staggered 255 front and 285 rear if possible. If this can work what back spacing is needed?
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Old 07-16-2017, 03:36 PM   #9
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Quote:
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So a couple new questions have popped up. Currently the car has an open rear with either 2.43 or 2.73 gears. It definitely needs an upgrade to some sort of posi/truetrac but I was wondering what ratio works best with these swaps and the 6speed?

Also i am looking at the year one 17" snowflakes. Can I do a 17x9 front with 17x10 rear under the stock body? I am looking to run staggered 255 front and 285 rear if possible. If this can work what back spacing is needed?
I have 17 x 9.5 front and 17 x 11 rear on mine with 5.5 inch back spacing on both. 275/40 and 315/35 respectively. Plenty of room for your wheel size. Stock body. Only seat belt hump needs a little BFH mod for mine. 10 inch rear wheel, shouldnt have to do anything.
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Old 07-17-2017, 07:09 AM   #10
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This is what my current setup looks like.

I added brackets fabricated from 1.5" angle aluminum and 1.25x.24" aluminum bar to eliminate firewall flex. Both masters are Wilwood. Brake is 1" bore, clutch is 3/4" bore.




Engine wiring harness block was moved to the right (from this view) about 1.5 inches to make space for a wilwood clutch master.
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Old 07-17-2017, 07:28 AM   #11
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Looks like a clean setup. I think that is pretty much exactly what I am going to try to do except for the addition of a 7" booster.
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Old 07-17-2017, 08:54 AM   #12
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You might be surprised at how well a manual brake system works. It gives you much better feedback than power brakes, but as you can imagine, requires a little more pedal effort. Thankfully our cars came from the factory ready for power or manual brakes. It is just a matter of positioning the brake master on the top two booster mount bolts and connecting a plunger shaft to the upper hole on the brake pedal.

This video shows my car pre-paint on the track with the big wilwood 6 pot calipers and manual brakes. Lots of speed up and slow down in a short period, from 40mph to north of 120.

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