ALBUQ F-1 thank you for the real world test of the PCV valve. I suspected it would throw off the fuel ratio, but didn't think it would cause that much of a problem. What oxygen sensor are you using? I would like to pick up an oxygen sensor, but want something easy to use at the tailpipe on the old cars I mess with.

 

I bought this setup off eBay,
http://www.ebay.com/itm/Innovate-3844-MTX-L-Digital-Wideband-Air-Fuel-Ratio-Gauge-AFR-UEGO-Kit-/191067182318?pt=Motors_Car_Truck_Parts_Accessories&hash=item2c7c7dd4ee
Several of the gurus on Ford Barn recommended it, and I found it to be a very good unit, with good software, too. Note it is 12v only! You can buy an accessory that clamps the sensor in the tailpipe, but best results are with it in the header or exhaust pipe (it needs hot gases, and if your exhaust system leaks at all it can throw it off).

PS -- I got it from the same vendor for $156, look around... although I suspect the increase is at least partly due to eBay fee increases.

 

glad to see some real world testing of the use of a pcv, valve setup.
when i converted my 'Y' block. i used a ford 4 cylinder engines pcv, valve. so maybe that's why i didn't see a significant change in engine performance.

my 'Y' block was installed into a 64 f100, running a 3:51 spicer rear. i averaged 16-18 on short runs and over 21 on the road. when the 55 mph speed limit was imposed, the engine was forced below it's optimum operating rpm, drivability and mileage suffered. the engine wouldn't run smooth at that low of rpm. (55 mph). as i was running a 312 police special cam in the little 272. 10:1 compression.

 

The "Toyota" PCV I went to is used on everything from 2.2L 4-bangers to 3.5L Lexus's. Even buying an aftermarket brand, it was amazing the difference in construction compared to the Ford 5.0 PCV. Instead of stamped construction with a plain flat disc "valve", it's a machined steel case with a precision plunger inside. But still had too much dilution to get clean AFR across the board.