Is it safe to use the driveshaft from a slant 6 904, on a v8 360 904?

When I install the u-joints (Im getting the spicer) Is there a certain direction the grease fittings should point too? is it just a matter of easiest location to get at?

I actually found SPL's cheaper then the 7260s. hmm?? and they have no grease fittings?

http://www.northerndrivetrain.com/product/SPI-5-788X.html

http://chucker54.stores.yahoo.net/spic72uj.html

Huh? found this one too... Grease fitting in the cap->
http://www.dennysdriveshaft.com/p465_7260_series_spicer_u_joint....grease_fitting_in_cap.html

Thanks!!