valve spring change with heads on the car?

[fiveohpatrol]

heres the situation, i have about 115k miles on my car and my valve springs are worn pretty bad, the valves float about 5400RPM, I have a new set of springs and will be installing them with the heads on the car

a friend of mine has a tool to do it with them on the car and a fitting for a air line to go into the spark plug hole to keep the valves from falling down while doing it

BUT i would like to do it this weekend so i can make it up to US41 the weekend after and im not sure if he'll be available to help me so...

is there any way to do it without the air compressor (i dont have one in my garage) say if i borrow the tool to remove the springs and hold the valves up in a different way, or is that the only way with the heads on the car,

i have removed valve springs before but the heads were off the engine

thanks for any help

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