Some of the IPL's for these saws mention that the 11625 clutch spider is a 'part change' (but don't mention the superceded part number). They also show that spider along with the chainbrake parts.........................and the illustration shows that spider as being somewhat offset (not flat). I'm wondering if the offset spider was needed to work with chainbrakes, and Poulan just changed the spider on all saws in that series.
A while ago I put an Australian market chainbrake clutch cover on a 3400 that I had for a while. The chainbrake band didn't seem to line up well with the clutch drum, and didn't grab it very well when the brake was engaged. I sold that 3400, but kept the chainbrake clutch cover and will be trying it on my 4000 soon. I'm eager to see if it works better on that saw. I also have two 3400 parts saws with clutches, and will eyeball the spiders on them to see if they're flat or offset...
The 253747/6119 seal is also used on both sides of an XL-12/SXL series Homelite, both sides of a XL-700/800/900 series Homelite (SXL-925, etc) as well as the FW side of the C/XP/2000 series large frame Homelites (1050, etc) and the PTO side of a 10-series McCulloch. Probably others too (in addition to the 3400-4000/PP375-395 Poulans and the Ropers)...