I'm getting ready to take my 4x4 f-150 on a 1000+ mile trip and I'm hoping that the beast will make it. My 76 390 is tired and has low oil pressure. Would it be a good idea to put a high volumn oil pump in with holley #90 jets in the heads? Would that cause too high of oil pressure?

 

doubt you'll have problems with too high oil pressure on any fe with some miles................the jet mod and some nice clean oil can raise the pressure some..........and if you ever did have to much pressure you could use thinner oil..........
try the jet mod and some 10 -40 or 20-50 oil and see how it responds before going after the oil pump.......it's cheap and relatively simple to do, so try it first and see what happens.. also, theres been talk fram oil filters can reduce pressure, so when you change your oil use the good ol motorcraft fl-1A filter..just to be sure......

 

I have a hv oil pump and the 90 jets in the heads,

I still have low idle pressure (not as low as it was, but low)

 

The jet trick will not raise the pressure that much. The problem is in the bottom. The jet will only help keep MORE oil to the mains/rods. This will help with longevity.


Larry

 

Ok guys, I havent heard of this jet trick yet. So a Holley Jet #90, but where does it go in the head?" I'm holding off on the block oiling job due to this it my only truck, but if this can help a little I'm willing to try it. Thanks fer yer info.

 

How low is the pressure? What's the pressure at 1K rpm, 2K, cruise? My Talladega has 5psi at hot idle. It comes up right off idle and has about 10psi per thousand after that. I run 20w50 oil and put it .090 restricters. They made absolutely no difference in my pressure. I could go HV pump, but was told it probably wouldn't make a difference either. My solution is to rebuild, and put in fresh bearings.

 

Xtreem, the jets go under the rocker stand that has the longer bolt that narrows to allow oil up to the rockers. Pull the rocker stands off slowly and evenly, then put the Holley jet into the oil hole that comes up on the side of the long bolt hole. It will fit in nice and tight and the galley makes a turn right away so it cant ever fall down. This will restrict the oil up top since FE's tend to fill up the valve covers with a HV oil pump since the oil doesnt drain back down that fast. This starves your main and rod bearings which is not good. The Holley #90 worked fine on my engine.

 

The usual cause for low idle oil pressure is worn or loose main bearings. The HV oil pump might help, but its only covering up the problem.

 

Thanks for the info. I dont think I need that at the moment, but it's always nice to know.