[Kenobi13]

Hey guys

So basically I am going to add the blower, long tube catless headers, gt haust exhaust system, lt4 high pressure fuel pump, kit also comes with injectors and intercooler. So also going to get engine and trans tune. Which will put us around 630-650whp max to be in safe zone.
But I really feel that I am spending already so much money I should spend a little more and get cammed fully build engine so I can push 800whp+ that is the goal.
What do you guys recommend to change on lt1 internal engine so I can be safe pushing 800whp+?
Also I am going to use the car for weekends and maybe do some races on Mexico but not really looking to build a drag car just want to have a lot of hp.
So my shop says that if you are not making a drag car just stay with 650whp but I feel if I am doing this I should do everything and have it 800whp+. Would it be reliable for a weekend car? So what do you guys recommend? Also will I be ok with stock trans it's 10 speed auto ?
What would the price approximately be for the internal build?
Also car only has 1k miles so it's like brand new


Thank you

[Puddin]

If your planning on going over 800 then your Lt4 fuel system isn't going to cut it. If your going to cam it you might as well do the rods and pistons at the same time since the motor will be practically be torn down to just a short block.

[Joshinator99]

Originally Posted by Puddin

If your planning on going over 800 then your Lt4 fuel system isn't going to cut it. If your going to cam it you might as well do the rods and pistons at the same time since the motor will be practically be torn down to just a short block.

Factory LT1 crank is forged and solid. GPI drop-in rods and pistons are beefy and can definitely recommend them.

[Kenobi13]

Originally Posted by Puddin

If your planning on going over 800 then your Lt4 fuel system isn't going to cut it. If your going to cam it you might as well do the rods and pistons at the same time since the motor will be practically be torn down to just a short block.

I gotchu but for 650-700whp lt4 high pressure fuel pump should be ok ?

[Kenobi13]

Originally Posted by Joshinator99

Factory LT1 crank is forged and solid. GPI drop-in rods and pistons are beefy and can definitely recommend them.

Oh I didn't know that thnx

[JSH]

Originally Posted by Kenobi13

I gotchu but for 650-700whp lt4 high pressure fuel pump should be ok ?

OEM LT4 high side fuel pump is good to +-825 wheel, corrected

[Idaho2018GTPremium]

For what its worth, the LT4 forged crank is stronger than the LT1 forged crank, so if you're going for 800 rwhp, definitely upgrade the crankshaft in your LT1. GM said during development of the LT4, they were breaking LT1 cranks at LT4 power levels under hard use, so they upgraded the LT4 crank to handle 650 ft-lbs reliably.

The other thing I'd worry at about at 800 rwhp is the transmission and other drivetrain components. The ZL1 w/ the LT4 ALSO has a stronger automatic transmission, which is called the 10L90, vs the SS and LT1 with the 10L80. The 90 means it has a higher torque rating, which in this case is around 700-715 ft-lbs of torque. I don't know what the torque rating of the 10L80 is, but obviously, less than the 10L90.

At 800 rwhp, I feel like your trans would be a ticking time bomb, since it isn't the L90. There's a reason GM beefed up the trans in the ZL1.


Also, on the street, the difference between 650 rwhp and 800 rwhp won't be felt until higher speeds when you can actually get traction with the tires. Even at 650 rwhp you'll spin quite a lot. At 800 rwhp? Even more.

[Kenobi13]

Originally Posted by Idaho2018GTPremium

For what its worth, the LT4 forged crank is stronger than the LT1 forged crank, so if you're going for 800 rwhp, definitely upgrade the crankshaft in your LT1. GM said during development of the LT4, they were breaking LT1 cranks at LT4 power levels under hard use, so they upgraded the LT4 crank to handle 650 ft-lbs reliably.

The other thing I'd worry at about at 800 rwhp is the transmission and other drivetrain components. The ZL1 w/ the LT4 ALSO has a stronger automatic transmission, which is called the 10L90, vs the SS and LT1 with the 10L80. The 90 means it has a higher torque rating, which in this case is around 700-715 ft-lbs of torque. I don't know what the torque rating of the 10L80 is, but obviously, less than the 10L90.

At 800 rwhp, I feel like your trans would be a ticking time bomb, since it isn't the L90. There's a reason GM beefed up the trans in the ZL1.


Also, on the street, the difference between 650 rwhp and 800 rwhp won't be felt until higher speeds when you can actually get traction with the tires. Even at 650 rwhp you'll spin quite a lot. At 800 rwhp? Even more.

Awesome thank you for the information 🙏