I have one as well. I have a mechanical autometer guage, and a heck of alot of line running to it also. when i get in it to crank it, i turn it over about 10 seconds and then flip the fuel pump on and let it crank. its cold out in the mornings, so the oil is thicker and will take longer to flow. i run 15-50 mobil 1. I run a pure one filter as well, biggest that fits. once i start it the needle jumps after about 1 to 2 seconds, just like yours, and then climbs on up to around 85 psi or so. it isnt instant 85 psi, i wish it would climb instantly, but it goes up kinda slow, takes about 5 seconds to get full oil pressure. Again, its cold outside during this time of year and the oil is thicker and will take longer. Like banning said, it may be a problem with the oil line to the guage, or something. The engine does get oil before the guage. When i start mine up, after its been sitting a long time, it will clatter for about half a second as well, unless i turn it over without fuel for a while to let pressure build, then it wont clatter. I dont see this as a problem, more of a nuisance. Im pretty sure its just a lifter, the lifters leak down after they sit and lose their pressure, and when i crank it up, it takes a sec for them (it) to pump back up and eliminate the clearance in the valvetrain. Thats all it is. its done it ever since ive had it, and ive seen alot of them that do it. it seems common to me