5.3 parts vs ls1 parts
 

dose any know how much shorter the ls1 water pump is then the 5.3 truck pump and same with crank pullys how much shoter is the ls1 then the truck. if we could go even more how much smaller is a ls2 water pump then a ls1 water pump again same with the pullys.im looking to get as much room in front of my motor as i can

The LS1 Vette front Acc. has the most compact fit. Ive personally checked this. 99-02 vette for sure is what I know of.

so do i want to use the ls1 or ls2 water pump for the most room?

As mentioned already, the Corvette FEAD (accessory drive) system will afford the most front engine room using factory components, as all the components are pulled in tighter to the engine. To give you a basic idea of how things play out with the various FEAD systems from the different platforms, using dimensions from the back-side of the pulley to the round bosses on the front timing cover: Corvette (.600”), Camaro/Firebird (1.00”) and C/K Truck at (2.250”). Also, dimensionally speaking, swapping from a LS1 to an LS2 car pump will not offer you any additional room.

Not to hijack, but are those numbers accurate? I have access to a Mill and am thinking about taking a truck tensioner down to the car height(LS1 F body), and when I was looking it didn't look like 1.25" difference between the two.... Thanks

John