I'm running a 1641 with slip in 87's.Been in my daily driver for 4 years,haven't had any problems yet.It's also got a counter weighted crank,30mm oil pump scat 110 cam dual 34 B Dellorto's,lightned & balanced flywheel,009 distributor,MSD 6 AL ignition with an electronic module in the 009,1:25:1 rockers,1 1/2 qt oil sump,remote oil cooler.1 5/8" headers with a custom made FlowMaster muffler.This motor has plenty of pep,a killer idle,and sets off car alarms crusing through town in 2nd.gear with the stinger on.Everybody asks "what's in that thing" when I'm idling at a red light or start it up at 7-11.Really pisses off those Mercedes and Bimmer owners at the restaruants,
(o\_|_/o)
My VW mechanic has built lots of motors with slip 87s and thinks they are the next logical upgrade for a nice street motor. I drove one of his 1641s for a few years and never had dramas with blow by or anything else. The difference between the stock 1585 and the 1640 was noticable.