-3AN or -4AN? oil pressure line
 

Trying to get everything together to install my oil pressure gauge. I think im just going to remove the factory oil pressure sensor and use a 1/8" BSPT to AN. fitting to a braided stainless steel line with a AN to 1/8" NPT female so i can screw my oil pressure gauge into that and mount it to the frame rail. I been told its not wise to mount it right to the block. Now my question is does it matter if I go with a -3AN or -4AN hose? Im not sure if it makes a diff. or not.

Thanks

-3 is fine

but 4AN would also b fine? I found 4AN local but can order 3AN if it makes a diff.

for oil gauge it doesnt really matter, for turbo feed it does matter which size with respect to whatever turbo it is