X2 on the 6 quarts should be perfect for oil/filter change on a 400 4x4 factory pan (be that way on all of mine). When you only have 6 quarts in there, how's the truck run? (like after putting a 100 miles on it... does it still smoke? plugs look just as bad?)

 

Hey guys,

You're definitely speaking about a "skeleton-in-the-closet" with Ford 351M/400 modified motors and oil reading.
Back in the day, here in Eastern Canada, my dad had a company van, a 1976 Ford E200 with 351M, and, it had a lot of engine issues. Always read a quart low on the factory (dealer maintained) recommended oil change.
We were a family of loyal Ford Brand Big Cars (71 Merc Marquis w/429, 71 LTD w/351 C or M, 72 LTD w/400M, 75 LTD w/351M, 76 LTD w/351M mostly with 351M & 400 motors.
The dealer career mechanic, and close family friend. told us that Ford wasn't going to put a recall on this issue as it would be too expensive, but would rather go through engine repair under warranty on an as-needed basis as long as regular service intervals and documentation were followed according to warranty specifications.
That protocol followed for the factory big-car line with 351M/400's as well, according to our family friend who is now 86-88 years old and was a career Ford mechanic through all
those crazy years.
Though I have no paper trail, nor do I have any actual mechanical proof, I was witness to Ford Dealer(s) putting a second Upper Mark on the dip stick to show where the additional quart of oil showed on the dip stick. Rumor at the time was that Ford was going to supply dealers with replacement dip sticks that had a relocated set of High & Low oil marks but I don't know for sure if that actually happened?

Curious to learn if any one else can chime in on this topic?

Good luck with your research into your engine issue.

 

Your sure the 2nd ring is on the piston the right way ? Depending on the mfgr. it can be hard to tell.

 

You have the same idea I had.

 

Rings are proper orientation. Problem is fixed. I actually had to replumb the pcv valve, my reinvention of the wheel of putting the pcv on the passenger side and a oil cap breather didn't work. After some troubleshooting I found that oil was being consumed through the pcv. I routed as per ford spec into the oil cap, that side has different baffles as well as locates the pcv higher, further from oil, and seems like problem is much better if not fixed completely. Thanks for the help.

 

It seems like pretty common practice around my 351m/400 to notice that capacity and oil stick aren't in correspondence, 6 qts on my 460 is right on, just changed it today. 400, 351m, not so much. I now have 2 4x4 400 sno fighters and one 400 2wd all 1978 trucks, as well as a 1978 351m 4x4. I can check each and every one and document and even change sticks around, 4 engines should be enough proof to put this to rest. We will follow up on this topic and see what oil capacity should be.

 

Glad you got it fixed. Keep em on the road and between the ditches. I have no experience with the 351m or 400, but it seems there is conflicting info between members. I'm curious to see the answer to the dip stick fiasco.

 

I started the 1978 snow fighter project this week. Guess what? 400, 4x4 oil pan, engine definetly been changed at some point, I drain, refill, 6 quarts, new filter, not as low as the others, but not to the full mark either. About at the bottom of add cold and the bottom 1/3 of safe hot. The skeleton is still in the closet. That makes the red 1978 sno fighter, the white 1978, the blue 1978 sno fighter and the brown 1978 1/2 ton 2wd and the old 1979 f350 4x4 I sold all same circumstance, 6quarts is not full yet. I bet the ford dealers were supposed to cut the tube off when these were new.

 

Hmm strange. Just to be sure are you letting the oil drain back to the pan after it's been running before you check the level? Is the truck on level ground?

 

Hey figured I ask this here before brake in,I have the 7 quart pan from L$L,,,,,reads proper at 7 quarts any advice /ete,to much oil for brake in,,,on 460

 

FWIW on my 400 the oil takes a long time to drain back after shutdown. I like to check after sitting a few hours. On the road at a gas stop, I never add oil unless the level is clearly below "add".

That said, and extra half quart of oil or even full quart should not cause the OP's problem. Glad he got it sorted out.