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Discussion Starter · #1 ·
I’ve been stuck on what I should do. At first I wanted to keep the LT1, get a head job, port everything, cam, and fuel upgrades. From what I’ve read that should get me close to 400. Recently I’ve had some circumstances come up that won’t allow me to start working on my car for a couple more months.

I have a 1995 TA with the T56. I planned on finishing the car before this coming summer but that’s not going to happen now. I plan now to work on it and have it finished at that end of next winter. My budget now is going to be around 14k Would swapping to an LS1 and doing similar upgrades be more cost effective to reach my 500hp range while still being reliable? Ill be doing 100% of the work on my own.

This will be my own first project ever. Over the past couple years I’ve helped my buddy get his car to make some serious power on a 4g63. I think I’m ready to tackle this bigger job but if it isn’t worth it monetarily then I’ll just keep the LT1 and build it up.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Are you looking for 500 HP at the flywheel, or at the rear wheels? Factory LT1 heads can be reworked to produce 500+ rwHP. Not necessarily a streetable configuration.

What is the purpose - straight line/drag racing, auto-x/road racing, fun daily driver?
 

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Chevrolet Performance Crate Engines. Right now you can get a 650HP/TQ LT4 for just over $15k. Golen Engine has a turnkey 440HP/480TQ LT1 with an amazing warranty for ~$7k.
 

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Discussion Starter · #4 ·
Are you looking for 500 HP at the flywheel, or at the rear wheels? Factory LT1 heads can be reworked to produce 500+ rwHP. Not necessarily a streetable configuration.

What is the purpose - straight line/drag racing, auto-x/road racing, fun daily driver?
Sorry, yes 500whp. Wanting a nice streetable build that can throw down when need be
 

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Discussion Starter · #5 ·
Chevrolet Performance Crate Engines. Right now you can get a 650HP/TQ LT4 for just over $15k. Golen Engine has a turnkey 440HP/480TQ LT1 with an amazing warranty for ~$7k.
As much as I’d like to go with something like that, I’m also planning on upgrading a lot of other things with my budget
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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For 500 rwHP the LSx will be the best bet. The downside of going LSx is that your T56 and the LT1 oddball “pullback” clutch is not compatible. And, it's getting harder to find a pullback style clutch that will handle high HP. McLeod just discontinued their LT1 Street Twin, and will no longer service existing units. I had one when my car still had the T56 and it handled 800 lb-ft and 5,000+ RPM dumps on sticky tires/track. There are more clutch choices with the LS1’s conventional pusher clutch.

Best thing to do is find a wrecked manual trans 98-02 Camaro Z28, Firebird Formula, or Trans Am, with the front end intact, and use the entire engine, trans, clutch, PCM, computer, harness, K-member, with complete suspension. Build the engine with the assembly sitting in your garage. When you're ready, raise the nose of your car, drop the LT1 assembly out the bottom, roll the LS1 assembly under the car, drop the nose and bolt it up.

You will have to work out the interface between the LS1 engine harness and it's interfaces with the 95’s body harness. Then work out the mismatches between the accessories - A/C, PS, and cooling. But with the free factory service manual downloads available, it shouldn’t be that hard. Unfortunately, I am not aware of anyone on this site that has done such a swap, and I don't see too many LS1 owners responding on difficult tech problems.

Have you considered keeping the LT1 and using a power adder to reach your goal? I have a 381ci LT1 that only makes 496 HP at the flywheel. Was kept fairly mild to allow it to be street friendly and meet NJ dyno emissions. When that wasn’t enough, it has two stages of nitrous (130 Hp / 170 HP) that tops it out at 800 HP / 800 lb-ft at the flywheel. And I seldom found it necessary to use the nitrous on the street. Of course 20+ years ago there were no 800 HP Hellcat Redeyes roaming the streets.

The LT1 block is exceptionally strong. It will support over 1,000 flywheel HP. The fastest/quickest T56 LT1 is running 6.9 second 1/4 miles @ 211 MPH with a stock block (although filled and destroked to 329ci). Estimated to be making in excess of 1,800 HP. You can buy a copy the T56 used behind the engine for $14,295…. but it only has the first four speeds, no O/D. :D
 
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Discussion Starter · #7 ·
For 500 rwHP the LSx will be the best bet. The downside of going LSx is that your T56 and the LT1 oddball “pullback” clutch is not compatible. And, it's getting harder to find a pullback style clutch that will handle high HP. McLeod just discontinued their LT1 Street Twin, and will no longer service existing units. I had one when my car still had the T56 and it handled 800 lb-ft and 5,000+ RPM dumps on sticky tires/track. There are more clutch choices with the LS1’s conventional pusher clutch.

Best thing to do is find a wrecked manual trans 98-02 Camaro Z28, Firebird Formula, or Trans Am, with the front end intact, and use the entire engine, trans, clutch, PCM, computer, harness, K-member, with complete suspension. Build the engine with the assembly sitting in your garage. When you're ready, raise the nose of your car, drop the LT1 assembly out the bottom, roll the LS1 assembly under the car, drop the nose and bolt it up.

You will have to work out the interface between the LS1 engine harness and it's interfaces with the 95’s body harness. Then work out the mismatches between the accessories - A/C, PS, and cooling. But with the free factory service manual downloads available, it shouldn’t be that hard. Unfortunately, I am not aware of anyone on this site that has done such a swap, and I don't see too many LS1 owners responding on difficult tech problems.

Have you considered keeping the LT1 and using a power adder to reach your goal? I have a 381ci LT1 that only makes 496 HP at the flywheel. Was kept fairly mild to allow it to be street friendly and meet NJ dyno emissions. When that wasn’t enough, it has two stages of nitrous (130 Hp / 170 HP) that tops it out at 800 HP / 800 lb-ft at the flywheel. And I seldom found it necessary to use the nitrous on the street. Of course 20+ years ago there were no 800 HP Hellcat Redeyes roaming the streets.

The LT1 block is exceptionally strong. It will support over 1,000 flywheel HP. The fastest/quickest T56 LT1 is running 6.9 second 1/4 miles @ 211 MPH with a stock block (although filled and destroked to 329ci). Estimated to be making in excess of 1,800 HP. You can buy a copy the T56 used behind the engine for $14,295…. but it only has the first four speeds, no O/D. :D
Thanks for this info. After some further research, I believe that buying a totaled ls1 Firebird will be what I do. As for clutch mine was slipping already so this’ll make it easier. As much as I want to keep the LT1, I’ll be spending about the same amount so might as well go for the swap. From what I can see the ls1 can handle 500-550 pretty reliably with a couple lbs of boost. My experience with building cars is limited but that’s not going to stop me. I’ll save the LT1 for my OBS v6 chevy whenever I get to that lol.
 
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