Running out of fuel on the big end..

[Posi67]

Maybe a little but then maybe nothing. Depends on how much of a change among about a dozen other things. I went down from a 4.86 to a 4.57 to kill off some top end RPM and my ET's stayed the same. I'd try shifting earlier and see if you pick up a few MPH. More top speed will obviously up the RPM in the lights.

Nothing worse than too much rear gear and running out of RPM or power at 1000'. It's just hard on parts for zero gain. You could also try a shorter rear tire to get a lower rear ratio although that isn't much. I have both a 29" tire and a 28" that are different brands. The shorter tire 60's better (because it hooks) and the taller tire seems to pick up about 1 MPH. ET's generally stay the same.     

[ec164]

I've read the posts and my question, looking at Pro Systems sheet what Hi speed jets are in it? I'm guessing a 32, try going to 28s or this much richer from what it has, then go back to your original jets the car liked best from your earlier runs. Go out and make a couple pass'es with new plugs at the end of pass shut it down, have your plug wrench with you and look, plugs will have color and you'll find a few MPH too! Patricks carbs come close, but that little adjustment should do the trick. IMO it's not fuel pressure or fuel system problem, gear or running out of engine.  Good Luck    Al

[bluef100fe]

I don’t think your mph is that that far off if at all for the ET. Couple years ago when I borrowed  a 454 inch stroker combo for a few weeks in my truck with a trans brake and mid-low 1.5 60fts, 4.57 gears, 31 tall tire, my then 4000lb F100 ran a best of 11.37 @ 116 mph. If memory serves it was running 6100-6200 in the traps. Just a 3/8 line to the carter M6905 pump and then double -8 lines to 1000 cfm Holley. I’m also in the process of upgrading my fuel supply system, bigger line, electric pump plus the mechanical. I’m also surprised you did an 8 jet swing and didn’t see any MPH/ET change.  Just another reference point for you. I would also vote for shifting a little lower and maybe  add a little gear.

[Falcon67]

Throw that Blue out in the field.  Get a 140 GPH pump - either a Holley black or Aeromotive, Magnafuel, etc.  Put in a return style system with the regulator on the return leg from the carb feed.  Blues are sucky pumps, especially in a dead-head type configuration.  The regulators aren't much to talk about either.  IMHO if you are running below 7s in the 1/8 and don't have neat $1K in your fuel system you are cheesing it out.  Even our 7.50 car has a return system and we never have any fuel delivery issues.  You WILL have issues with a dead head system.  It's been seen on the dyno - the fluctuations in the regulator stop/start hit the needle/seat combo and promote fuel foaming in the bowls. 

[BattlestarGalactic]

My .02, I tried to skim through the pages of info so far.

Seems the shift rpm is way up there?  Have you tried lowering to 6500-7000 and see if it picks up(1/8 or 1/4)?  Your ET and MPH isn't too far out of whack math wise.

You are very close to my set up, sorta.  I've got a 462, with hand ported Eboks, .63 flat tappet, tunnelwedge w/2 1850's.   Made 625 @6500.  It's 4000# with me.  I have 4.56 gears, 29.5" M/T.  Typical hi 1.4's(1.50 on greasy track).  Have been 1.41 on really good track.  I leave around 5000, shift at 6500, trap 6500.

I run comparable numbers, 11.0's @ 120-121 and 6.9's @ 97.

I have a 140 mallory with return line.  I agree, dead head systems are not optimal for what you are trying to do.  I used to have a return system with a Holley blue, but that pump failed too many times and I switched to Mallory. 

If you didn't pick up jetting it up that much, then it's not getting enough fuel?

[mbrunson427]

I also think you may be shifting a bit too high. We fiddled around with shift RPM on our '64 Fairlane for what seemed like a whole season, changed shift points, changed rears gears. This was a 482 so it had the same crank as yours, probably about the same kind of power too. What we ended up finding is it really liked the rpm band right around 5600-6400. Started with a 4.56 rear gear and settled on a 3.91. When starting out we thought that it needed to be spun high and really ripped on to make a good pass but what we ended up was a lot more conservative and it ran faster. In hindsight it would have paid for itself in gear changes just to put the engine on the dyno to see what it liked. That car ran consistent 11.10's up here in Denver altitude.

[64PI]

That is some good info. I've never though about needing to run a return line but it makes sense. I will have to do some research on how to set it up and what fuel pump/regulator I want to run. Does anyone have any experience with the Pro Systems fuel pump and regulator?

[BattlestarGalactic]

Do you run a stock tank or fuel cell?  That will come into play on getting enough fuel also.
I ran my stock tank for years, but put fittings in the back for pickup.  The return I just put a fitting in the front by the sending unit.  The wagon tank is tall, wide box, unlike a sedan which is a flat box of sorts.  I would recommend installing a sump in the rear if you haven't already.

Do you have 1/2" line now?  I just ran a second 1/2" line for my return.  Big?  Ya, but it is not a restriction.  Been that way for nearly 20 yrs.  I have a Mallory return style regulator.  It has a vacuum port to cut the pressure at idle(high vacuum), but don't use it.

[64PI]

I'm running a fuel cell with foam. It has 2 AN fittings out the rear of the sump and one vent line out of the top. I am only using the one outlet on the sump now.  Would I be safe to use the other fitting as the return side? I'm not sure if having the return that close to the pickup would cause an issue. I do know you want the return below the fuel level. And I am running 8AN line now the whole way.

[Falcon67]

You want the return back and away from the feed port to reduce the chance of sucking foamed fuel into the line.  Most fuel cells should have two fittings on the top, at least all the off-the-shelf aluminum ones I have used do.  One for vent that you top with a roll over check valve and vent line, the other for return.

X3 on the Mallory units, have two.  I've never had a fuel issue with #8 lines on the door cars.  The dragster runs methanol, so that's #10 from the cell/A1000 pump and #8 back to the tank.  Lotsa volume.