Thread: It looks like I will have to start over

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I have a 1970 302 in my 65 custom 500 with shorty headers and a good exhaust and finally got it tuned where it was running great but I decided to get the matching valve covers for the mid 80s mustang dual snorkel aircleaner so I could hook up the crankcase ventilation like it was on the mustang and its back to running like it was before. The only difference was I had to use a longer hose for the PCV since it was on the pass side originally and on the mid 80s mustang valve covers the PCV was on the drivers side so I dont see how a longer hose could lean the motor,its back to being lean and not running its best untill its warmed completely up and then its really not its best. The next time I get to Jegs I am going to get a carb spacer that has a PCV port so I can run it out the front and cut down the length of the hose and see if it returns to the way I had it or it looks like I will have to richen the carb up a little again.

Strange deal Jeff.... Did the hose relocate just from side to side, or from front to back??? Have seen folks have issues when the PCV comes off the back end of the cover..... No idea why...

On the original 70 valve covers the pcv went in the pass side at the rear and on the 80s mustang valve covers the pcv is on the drivers side in the front,it has a holley carb and the pcv port is close to the original 1970 location so a short hose was used but when I installed the later valve covers I had to use a 2 foot long hose since there was no other place to hook up the hose for the pcv. The mustang got the vacumn for the pcv from the carb spacer in the front so I will try to duplicate it with a aftermarket carb spacer as the mustang carb spacer is made for a egr which I dont want to use,it seems strange that a longer hose would lean the motor but it did.

Curious to hear if the spacer fixes the lean condition????

Originally Posted by Dave Severson

Curious to hear if the spacer fixes the lean condition????

Me too, Dave. Could your PCV be bad, stuck open so it's sucking instead of only eliminating positive pressure in the crankcase? Not sure it could be enough to lean our your mixture a little? Just a thought, this one's a head scratcher.

I do have a AFB that has a pcv port in the front of the carb that I could try but all I know is I need to shorten the hose to the pcv and see if it returns to the way I had it,I went up 2 sizes on the jets and it made a big difference and got rid of the pinging and got crisp throttle response but I am back to square one now. I am not going to go larger on the jets untill I get the spacer and shorten the hose but I did not think a longer pcv hose would lean it back out.

Originally Posted by junkyardjeff

I do have a AFB that has a pcv port in the front of the carb that I could try but all I know is I need to shorten the hose to the pcv and see if it returns to the way I had it,I went up 2 sizes on the jets and it made a big difference and got rid of the pinging and got crisp throttle response but I am back to square one now. I am not going to go larger on the jets untill I get the spacer and shorten the hose but I did not think a longer pcv hose would lean it back out.

It won't. Unless it's full of holes.

I used new hose and I had to use the pcv that is for the newer valve covers,if the new valve covers are physically larger then what I took off could that be part of the problem. If I feel like going anywhere sunday I might head to Jegs and get the carb spacer but the trip to Detroit saturday might make me feel like staying home.

I kept a Carter AFB off a truck I recently sold and since it has a front port for a pcv I installed it tonight and its back to where it was before the valve cover change,dont know if its jetted richer or shortening the hose for the pcv but its back and running great. Now its time to put the electronic ignition back on,if I only known it had a adjustable vacumn advance when I took it back out I could of had it set right. I robbed the vacumn advance for the distributor in my sunliner so I had to order another tonight and need to make up another harness since I used the one I made for the 65 on my 66 F250 when the 460 went in.