[Chrome383Z]

My car ran 48-49 psi cruising and 68-70 psi WOT when I was bolt on E85 GPI tuned. This was with the stock LT1 pump if that provides an additional datapoint.

[KingLT1]

You can command more pressure in the tune...in fact you have to do this on the earlier SS cars to get the pressure higher even when swapping to the LT4 low side pump. I believe 19 on up command higher pressure on the low side. That might be why there was some discussion about 2019 on up getting the LT4 pump when in reality it's still the regular LT1 pump commanding more pressure. Now what I have noticed is that I believe in 2020 or 2021 for LT1 models the part number for the pump is the same for the ZL1 on gmpartsdirect.com.

At this point it might be easier to email somebody like Ted Jenetty and see what he has found. I would be willing to bet he has probably changed pumps on a 2020+ LT1 model.

[LT1ornothing]

Originally Posted by KingLT1

You can command more pressure in the tune...in fact you have to do this on the earlier SS cars to get the pressure higher even when swapping to the LT4 low side pump. I believe 19 on up command higher pressure on the low side. That might be why there was some discussion about 2019 on up getting the LT4 pump when in reality it's still the regular LT1 pump commanding more pressure. Now what I have noticed is that I believe in 2020 or 2021 for LT1 models the part number for the pump is the same for the ZL1 on gmpartsdirect.com.

At this point it might be easier to email somebody like Ted Jenetty and see what he has found. I would be willing to bet he has probably changed pumps on a 2020+ LT1 model.

I really hope so. Historically, he keeps a eye on these threads and chimes in. There are several of us who could use some clarity on which low side pump the LT1 trims (2020+) comes with from the factory.