Holley 390CFM tuning 258

ramblin64sw wrote: On my 4.0 valve cover, I replaced the the metered fitting at the back of the valve cover with a push in style pcv valve. I've had no issues, I can dig up part numbers if it helps you. I think it was off a chevy 250? Don't give up, it will be worth the effort in the end! As Farna say's, take it one problem at a time.

That sounds like it could work. I'm hoping it has a pretty stiff spring as the engine pulls a lot of vacuum.

This is for a 83-86 CJ with the 6 cyl. Could work

You are working with a 2 bbl carburetor looking to install a proper operating PCV system. The cfm rating is pretty much a standard number for the OEM or equivalent application (such as other manufactures engines) and such a small percentage of the carburetor rating that vacuum resistance as you refer to it as, is pretty much a non issue leaving fitment as the major issue. Your I-6 motor is hardly an unusual configuration to "hot rod". It was at one time a serious player in off road racing and in some circles it is still a player in circle track racing. I have or still have up to six of them. I use the standard as supplied PCV valve for the 258 engine in an OEM configuration with no tuning problems for an OEM bone stock 258, a258 with a cam, compression and a 2bbl, a 258 with cam, compression and Port Fuel injection and a 232 with a cam and a 4bbl. All with no problems.
I use as a symptom as being miss applied or an indicator of a problem if the filter used for incoming air becomes oil soaked either internal crank case pressure is too high due to blow by or the cfm rating is too small. As the indicator shows no problems and tuning is not an issue the "vacuum resistance" is a non issue and can be ignored

I got a PCV for a '88 Wrangler 4.2L. I think these are the same '83-90
It's called PCV376 and was $2
I had to use it with the Ford PCV Grommet (Dorman Help! 42324) off the shelf at O'Reilly to make it fit since the 4.0L PCV has too big of a hole (also on the shelf at O'Reilly)
When I was installing it I found this - the bottom had popped off the elbow


Here is the new setup


I readjusted everything and have it set at
600RPM idle
11 degrees advance
18.5 inches vacuum

I'll test drive it after I get the new front shocks to reevaluate under load.


Edited by 71hornet6 - May/03/2016 at 6:21pm

What kind of choke setting should I have for the electric choke?
I'm guessing I want it more rich because of the unheated manifold
The engine needs to be cold to test it so it would be helpful to start in the ballpark






Edited by 71hornet6 - May/06/2016 at 8:12pm