I added a PCV to my 49 216 back in 2013 and it reduced the amount of smokey blowby from the 3 valve cover vents and didn't cause any problems with overall engine performance. I originally tried Deve's mod but the lower end of my 216's engine is well worn and produced too much oil film residue in the intake vacuum port. So I modified the draft tube to put more baffles and space between the PCV and crankcase and this reduced the oil film deposits in the intake to almost nil...
Below is a copy of the final setup thats I've been running for approx 20k miles. The vacuum wipers do work and have worked many times with this final setup.

Originally Posted by Volfandt
Update. Heres a pic of the PCV mounted in the road draft tube. It is still a temp setup so don't mind my little rigged up strap to hold the PCV into the grommet.
I figure the gorilla glue will eventually let loose and when it does I have a 30.08mm freeze plug that I will drive into the road draft tube w/a proper grommet that will hold the PCV. Until then this works grin

I went w/a PV1053 PCV is is the straight eqivilent to the 90 degree angled PV 141. The straight PCV lined up better.

The larger PCV that I tried and didn't work was the PV233. It is all metal and also straight but came w/a 90 degree adaptor. IT would stay in the glued in grommet without my rigged up strap but unfortunately is too large and draws too much vaccum which negatively effected the vaccum windshield wipers.
Dave

1949 Chevy 1/2-Ton 3100
1949 GMC 1/2-ton 100
In the Stovebolt Gallery
More pix on Photobucket
Video of the 216 running
Video of a Winter Cruise