Resurgence of a F100

6speedsd

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Did a little tinkering today. I talked to Comp, and they say I should be at nearly 17" of vacuum at idle with this cam. I'm at 10. I advance the timing from 12 to 14, which got me up to 12" vacuum. Readjusted idle screws, turn and a half seems to be the sweet spot for the most vacuum. Any more or less and it'd drop to 11. Rechecked for vacuum leaks...carb cleaner sprayed around all connections, base of carb, throttle shafts, and all around the intake manifold/head surface. No change what so ever. Went for a drive, and damn does this thing like more timing. Much snappier when you hit the skinny pedal, and it almost...not completely....got rid of my stumble at light throttle.

When I got back, I hooked my advance up to full manifold vacuum, just to see what my advance was pulling. At idle, it was advancing to 34 degrees.

I'm making progress I think. Electric choke has stopped working now for whatever reason. I have 12v key on to it, and it's set almost straight up in the middle of the scale. Always something I guess.

Did a burnout...I guess you could call it that. It breaks them both loose rather easily, but I have axle hop some kinda bad. Whole truck was lunging...so I let off and didn't press my luck. The rear leaf springs are super soft..nice for a comfortable ride, but not so much for performance.

I know rear gearing would be night and day with this truck, but without some sort of OD, it would be undrivable at freeway speeds, which is 90% of my driving. I'm pushing 3000rpms now at 75...a better gear would have me 3500+, and that's just not feasable.

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mandkole

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You’re measuring vac in park/neutral right?

Here’s some other reference info..
 

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psduser1

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Did a little tinkering today. I talked to Comp, and they say I should be at nearly 17" of vacuum at idle with this cam. I'm at 10. I advance the timing from 12 to 14, which got me up to 12" vacuum. Readjusted idle screws, turn and a half seems to be the sweet spot for the most vacuum. Any more or less and it'd drop to 11. Rechecked for vacuum leaks...carb cleaner sprayed around all connections, base of carb, throttle shafts, and all around the intake manifold/head surface. No change what so ever. Went for a drive, and damn does this thing like more timing. Much snappier when you hit the skinny pedal, and it almost...not completely....got rid of my stumble at light throttle.

When I got back, I hooked my advance up to full manifold vacuum, just to see what my advance was pulling. At idle, it was advancing to 34 degrees.

I'm making progress I think. Electric choke has stopped working now for whatever reason. I have 12v key on to it, and it's set almost straight up in the middle of the scale. Always something I guess.

Did a burnout...I guess you could call it that. It breaks them both loose rather easily, but I have axle hop some kinda bad. Whole truck was lunging...so I let off and didn't press my luck. The rear leaf springs are super soft..nice for a comfortable ride, but not so much for performance.

I know rear gearing would be night and day with this truck, but without some sort of OD, it would be undrivable at freeway speeds, which is 90% of my driving. I'm pushing 3000rpms now at 75...a better gear would have me 3500+, and that's just not feasable.

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Sounds like you are gaining! Keep tinkering, you should gain a bit more. I wouldn't get to excited about the cam manf guesses about available vacuum, lol, but you should be able to see 15ish. I dont know what your cam profile is, but I could pull around 15-16 inches with a .600+ lift cam in a sec. Under most conditions, any way. As you spend time adjusting things, I expect you'll realize that numbers on paper dont mean that much on an individual engine, if you haven't already! There really is an art to making a carbed engine happy.

As far as rpms, have you considered an eros? Dont know if you want to stay that far from stock?
 

psduser1

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Also, what rpms is your idle set at? I know you dont really like your tach, so maybe get that sorted out, as idle rpm will affect the vaccuum reading.
 

6speedsd

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Actually, now that I think about it, I did measure today with it in Park. I was thinking about the other day when I replied previously.

A little funny story...when I was advancing timing today, I didn't loosen the distributor hold down clamp up much before I tried to turn it. I grabbed the top, across the plug wires, and started twisting. I guess I twisted a little too much at the wrong angle because a couple plug wires popped off the cap, and I got the shiz shocked out of me. I haven't had a good tingle like that in a while. You don't think about that much current in a DC system, but between the Blaster coil and MSD box, it's got some fire to it!!

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6speedsd

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Also, what rpms is your idle set at? I know you dont really like your tach, so maybe get that sorted out, as idle rpm will affect the vaccuum reading.
Today, after adjustments, I had it set...according to my current tach...at about 750-800 in Park. In gear its 600ish.

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psduser1

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Try dropping rpms 25-50 at a time, in park. That sounds a touch high. That can dramatically change vaccuum readings.
Every adjustment you make affects everything else, lol. About the time you feel like you are chasing your tail, you'll be spot on!
Be aware dropping rpms will affect your off idle performance-usually in a bad way-so you'll have to compensate with carb adjustments.
 

mandkole

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No, in D. Everything I've ever seen says to measure it in gear with an auto.

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You are not going to pull 17 in gear.. especially with a tighter converter. I agree you check it in gear when you are trying to size the power valve. The 6.5 is fine.
 

6speedsd

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I actually had rpms set at about 650-700 before today...truck just sounds so much better at that rpm. Yeah I know...it ain't all about the sound. It was really fat at that low of an rpm though, but I was also at less timing, and less vacuum.

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6speedsd

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You are not going to pull 17 in gear.. especially with a tighter converter. I agree you check it in gear when you are trying to size the power valve. The 6.5 is fine.
But I'm still only at 12, in Park. I really don't know where/why else I could be losing vacuum. Or not really losing it, but not making more than 12


Should I even be this concerned over only make 12"?

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psduser1

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Gonna have to explain this one to me. Eros the brand or am I way off?

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Autocorrect. I thought I typed "rpm", apparently my keyboard couldn't read my mind again. Sorry.
If your idle is that lumpy at 6-700 rpm, you may have raise the idle.
 
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PDT1081

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But I'm still only at 12, in Park. I really don't know where/why else I could be losing vacuum. Or not really losing it, but not making more than 12


Should I even be this concerned over only make 12"?

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Have you pulled the plugs at all? I'm not familiar with Fords, but have had an intake gasket leak from the lifter valley on a Chevy before. They're a bitch to chase down.
 

6speedsd

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Forgot about this for a couple days. Weather has been nasty lately and I've been lazy. 3" of rain in the past 36hrs, and calling for another 3-5" over the next 2 days. Anywho...I pulled all 8 plugs this afternoon. All look the same, all have a light brown/tan-ish color the tip, electrode is clean. All look normal to me. I did open gaps up to .040", originally set them at .035". Will run a little and see how it behaves. With the MSD box and coil I should be fine with a bigger gap.

I feel like an idiot for over looking this so much, but it hit me today that I never hooked my PCV back up on this thing. Got that reconnected to the PCV port on the back of the Holley...didn't seem to affect vacuum much, if any, but it idles slightly better it seems. I'll run it some whenever the rain decides to go away and see if anything changed...not expecting anything but who knows. Idle didn't smell as fat after opening the gaps and hooking that PCV back up, so maybe I'm on to something.

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6speedsd

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So, a little glimpse into how my luck goes....

Now that I’ve done the work to this 302 and have it running pretty good...and spent all my put back cash....guess what pops up on my local CL....here in my town to be exact? A 69 351w, complete engine top to bottom. Been sitting in a shop for 30 years. Son of a.....guy is asking $300 for it. Not sure if it’s worth that or not considering how long it’s been sitting, but I’m tempted to go get it. Just put it on the stand and hold on to it through the summer until work slows down next fall...if I can talk momma out of a little bit of her secret stash. From everything I’ve read to date, it seems like the 69-70 models are the desirable ones.


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lincolnlocker

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So, a little glimpse into how my luck goes....

Now that I’ve done the work to this 302 and have it running pretty good...and spent all my put back cash....guess what pops up on my local CL....here in my town to be exact? A 69 351w, complete engine top to bottom. Been sitting in a shop for 30 years. Son of a.....guy is asking $300 for it. Not sure if it’s worth that or not considering how long it’s been sitting, but I’m tempted to go get it. Just put it on the stand and hold on to it through the summer until work slows down next fall...if I can talk momma out of a little bit of her secret stash. From everything I’ve read to date, it seems like the 69-70 models are the desirable ones.


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Oh wow. That would be great! But sitting for a long ass time. Does it roll over at least?

live life full throttle
 

6speedsd

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I have no idea Jake. Haven't even called the guy yet. I'd imagine the rings are stuck at the least. It would definitely have to be gone through regardless. But sitting inside a dry shop for that long, how bad could it be really?

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