They used them on the Small blocks at least thru at least thru 67 rather than recast the blocks to eliminate the opening. On PCV equipped cars/trucks the road draft tube was eliminated and the adapter with a nipple like his engine has was used with 2 sections of hose and an inline PCV connected to the Carb base (fresh air was pulled thru the oil filler cap). There is also an oil baffle that goes with them inside the lifter valley. The "newer" 68/9 Small Blocks eliminated the part of the casting where the PCV adapter/road draft tube went and the PCV was moved to the valve cover.

The adapters with the nipple for the PCV hose and the extra long bolt for them are still available in reproduction (for about $90 the last time I checked...... thank god for old wrecking yards ).


I went thru all that crap when I did the little 1960 283 I built a couple of years ago



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