Rebuild or Swap the LT1
07-25-2005, 07:35 PM
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Rebuild or Swap the LT1 Hi Folks,
Well, it's time to start thinking about rebuilding the LT1 in the '96 Impala SS. It's gone 180k miles and has a fair number of road-course track days on it, too. She's starting to make some noise and loose some grunt.
The engine is a stock B-Body LT1, except for an underdrive crank pulley and 1.6 CompCam roller-rockers. I am thinking about replacing it with something only slightly more exotic. Stock spec was 260 rwhp and 340 ft-lb torque (I think). The Impala is a 4,400# car that loves the big torque number.
Can you think of any reason that I shouldn't go with a forged, solid-roller, .030 over setup with a P&P to the stock iron heads and a mid-lift cam? I don't mind lashing the valves every so often. If I am going to rebuild, I may as well get the most bang-for-the-buck. I am not thinking stroker here, because I don't want to replace the rest of the drivetrain all at once ...T/C, trans, posi, and axels... which is the normal upgrade path for an Impala with big power mods. I will get the hardened drivetrain parts as they wear out.
I have the Ultima coming for my track-day car, so I don't need/want to go balistic with the Impala. But, it would be cool to have a big'ol sleeper.
Your suggestions as to build specs and vendors are appreciated. Also posted on a couple of Impala boards.
Well, it's time to start thinking about rebuilding the LT1 in the '96 Impala SS. It's gone 180k miles and has a fair number of road-course track days on it, too. She's starting to make some noise and loose some grunt.
The engine is a stock B-Body LT1, except for an underdrive crank pulley and 1.6 CompCam roller-rockers. I am thinking about replacing it with something only slightly more exotic. Stock spec was 260 rwhp and 340 ft-lb torque (I think). The Impala is a 4,400# car that loves the big torque number.
Can you think of any reason that I shouldn't go with a forged, solid-roller, .030 over setup with a P&P to the stock iron heads and a mid-lift cam? I don't mind lashing the valves every so often. If I am going to rebuild, I may as well get the most bang-for-the-buck. I am not thinking stroker here, because I don't want to replace the rest of the drivetrain all at once ...T/C, trans, posi, and axels... which is the normal upgrade path for an Impala with big power mods. I will get the hardened drivetrain parts as they wear out.
I have the Ultima coming for my track-day car, so I don't need/want to go balistic with the Impala. But, it would be cool to have a big'ol sleeper.
Your suggestions as to build specs and vendors are appreciated. Also posted on a couple of Impala boards.
07-25-2005, 09:53 PM
#2
Unless you are looking to boost or spray the stock rotaing assembly is great don't wast money on forged.
I don't think you realize how far you can go with a hydraulic roller, unless building a track only car stay with hydraulic.
As far as the heads I am sure a lot of ignorance will show up shortly but there are exactly two disadvantages to the stock iron castings one being pressed rocker studs which for perfomance use should be pulled and tapped for screwin and second is the weight, but this is a heavy pig of a car so who cares about the weight it is under 50# according to recent weighings by myself and a CamaroZ28.com member, so ju8st over 1% no biggy.
As far as the drivetrain the tranny is the weak link and TC upgrades can be amazing performance improvers, the stock posi will wear out though but is not likely to violently fail, the axles will take you a whole lot further than you are looking to go. The 30 spline 8.5" 10 bolt we have is comparable to the 12bolt of old, there are 10 second cars with nothing more than gears and a posi done to it.
Oh and stock is 330TQ.
I don't think you realize how far you can go with a hydraulic roller, unless building a track only car stay with hydraulic.
As far as the heads I am sure a lot of ignorance will show up shortly but there are exactly two disadvantages to the stock iron castings one being pressed rocker studs which for perfomance use should be pulled and tapped for screwin and second is the weight, but this is a heavy pig of a car so who cares about the weight it is under 50# according to recent weighings by myself and a CamaroZ28.com member, so ju8st over 1% no biggy.
As far as the drivetrain the tranny is the weak link and TC upgrades can be amazing performance improvers, the stock posi will wear out though but is not likely to violently fail, the axles will take you a whole lot further than you are looking to go. The 30 spline 8.5" 10 bolt we have is comparable to the 12bolt of old, there are 10 second cars with nothing more than gears and a posi done to it.
Oh and stock is 330TQ.
07-25-2005, 11:53 PM
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Originally Posted by 96capricemgr
Unless you are looking to boost or spray the stock rotaing assembly is great don't wast money on forged.
I don't think you realize how far you can go with a hydraulic roller, unless building a track only car stay with hydraulic.
As far as the heads I am sure a lot of ignorance will show up shortly but there are exactly two disadvantages to the stock iron castings one being pressed rocker studs which for perfomance use should be pulled and tapped for screwin and second is the weight, but this is a heavy pig of a car so who cares about the weight it is under 50# according to recent weighings by myself and a CamaroZ28.com member, so ju8st over 1% no biggy.
As far as the drivetrain the tranny is the weak link and TC upgrades can be amazing performance improvers, the stock posi will wear out though but is not likely to violently fail, the axles will take you a whole lot further than you are looking to go. The 30 spline 8.5" 10 bolt we have is comparable to the 12bolt of old, there are 10 second cars with nothing more than gears and a posi done to it.
Oh and stock is 330TQ.
I don't think you realize how far you can go with a hydraulic roller, unless building a track only car stay with hydraulic.
As far as the heads I am sure a lot of ignorance will show up shortly but there are exactly two disadvantages to the stock iron castings one being pressed rocker studs which for perfomance use should be pulled and tapped for screwin and second is the weight, but this is a heavy pig of a car so who cares about the weight it is under 50# according to recent weighings by myself and a CamaroZ28.com member, so ju8st over 1% no biggy.
As far as the drivetrain the tranny is the weak link and TC upgrades can be amazing performance improvers, the stock posi will wear out though but is not likely to violently fail, the axles will take you a whole lot further than you are looking to go. The 30 spline 8.5" 10 bolt we have is comparable to the 12bolt of old, there are 10 second cars with nothing more than gears and a posi done to it.
Oh and stock is 330TQ.
My tranny was rebuilt at 95k...85k ago. So, I don't think it will take too much more abuse. When it starts to let go, I will get something better (maybe from TCI). The posi has held up to my daily thrashing. I slide corners, downshift, and run it to tripple digits every day, so I am happy about that. But, sooner or later, something's got to give. I will be looking at an Eaton or Torsen. The axles should be fine...did the Felpro gasket mod early.
Do you know of a good supplier for these engine components? Someone that really knows the LT1?
Thanks,
