Hey guys. My 460 is one helluva slug. So much of one, it can't even chirp tires off the line when floored. Not a single chirp. Everyone I've ever heard talk about there things is that they can melt tires without even trying.

Currently set up as follows:
- '71 timing chain set "straight up"
- Dizzy recurve with 20* centrifugal advance all in @ 3200rpms (set so I can tow eventually and not ping)
- Initial timing set at 14*
- Vac advance unit is the adjustable Crane unit. Set screen twisted all the way IN.
- Edelbrock 1406 carb calibrated to stock baseline.
- Stock exhaust, heads, short block and intake

Stomp it off the line and it bogs then slowly revs from there. Stay on it and it chokes and wants to die.
Stomp it while rolling and it waits a bit and then goes. Pings a tad at that point.
Town driving is nice though! Very responsive to light throttle, and on the primaries it feels pretty smooth.

What am I missing? No way in hell the only way to get this turd to spin the tires is to stuff a holley or demon carb on it. I'd like to calibrate what I have.

When I got the truck, it had an edelbrock 1411 on it. Drives similar to the 1406, only the WOT bog is waaaaaay worse. Figured it was over carbed, bought the 1406 and here I am. Have rods and jets coming in the mail to convert the 1406 into a 1405 so it'll richen up...if that even is the problem.

Plugs look okay. Greyish white across all 8. Tan at the very base. NO residue on them.

Rear end is I believe a 4.10 9".

Truck in question is my 77 F150 supercab trailer special.

I realize it's an 8:1 compression motor with stock D3ve heads. I realize it's in a 4000lb truck. But this is just plain bad!


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So it's 34° "total" mechanical timing? (vacuum advance port disconnected and plugged)

 

Assuming its a 2wd auto from your profile info. Timing seems appropriate except backing off the vacuum advance screw a bit might help with the rolling pinging. It sounds like you have carb problems. Make sure you have no vacuum leaks and a healthy vacuum. If you don't have a vacuum gauge get one and use it to tune the idle circuit on the carb. Also verify you are actually rich before you adjust rods and jets, it might already be too rich. If you arent sure on the rear end it could make a big difference. If you have gear ratio closer to 3.00:1 it will struggle a bit. I had a 77 with 351m and 3.00:1 and it would spins tires but with clutch persuasion. Automatic takes a lot of power away.

 

Yep, I'm betting on a vacuum leak someplace.

 

Probably a vacuum leak, if you can't hear it take a can of break clean and go over the intake seams,hoses ect, if you hear the rooms raise you found it

 

I don't have anything to add so I'm sorry for bumping your thread but that last bit made me chuckle.

 

Been through over 2 cans of brake cleaner looking for leaks and still have nothing. Not so much as a stumble. Sprayed the inake, carb base, spacer base, vacuum trees, brake booster, vacuum pod for cruise control...if it's vacuum, it's been sprayed!

she holds 18-19" vacuum while idling at 750rpms in park.

Dizzy is set up with the 15L slot engaged on the stop with the 2 yellow springs from the crane kit. Should give me 30* inside the dizzy. Crane then recommended going with 2* above stock spec (which is 12*) and running it at WOT to see if it pings. It didnt. Hooked up vacuum advance, and the rest is history as they say.

So...timing is set to a whopping 44* TOTAL. Vacuum advance hooked to manifold vacuum as they recommended. Sounds good yes??

Jacked up the rear end tonite after work. It's definitely a 4:10 back there.

I judged it being lean because of the plugs. I know tan grey is the best color. Mine are white grey.

 

Stupid autocorrect

 

First thing I would do is double check that the 0 balancer timing mark is for sure TDC. If that's good, then I'd move to the carb.

"Too much" carb is usually NEVER a problem unless you're putting a 1150 Dommy on a 3 cyl Geo Metro.

If it bogs, it needs more fuel. They will run ok even when they make your eyes water from being rich, but it can't make power if it does not have fuel.

Hope you get it sorted.

 

Have you checked fuel pressure? My truck had ok pressure at idle but if it went off idle it bogged. My tank wasn't vented properly and it was creating such a vacuum it starved itself for fuel off idle I switched gas caps and problem solved

 

Simple check - ziptie the secondaries in your carburettor closed, or adjust so they open later. I bet they are opening too early.

I have a LandCruiser troop carrier (2-door station wagon) with a 351C and it was a *dog* until I completely went through the Holley 600 it was fitted with. Did exactly as you said above - bogged badly and choked up top.
Turned out to be overly rich mains combined with secondaries opening waaay too soon (causing the bog) and a bad power valve (poor part and full throttle performance). Vacuum leaks made the thing unpredictable, too - depending on the day it would perform better or worse!

Cheers - boingk

 

You may also want to check your accelerator pump. It may not be adjusted properly. On my 1406 there are three settings and two of them will make mine stumble and stutter.

 

I fought mine for years. The darn thing just wasn’t putting enough gas in the carb for wot. It turns out that years ago the mechanical pumps for trucks were heavy duty and in time the pumps for cars and trucks were the same. I finally put a 90gph electric pump on it and it turned into a beast. That shouldn’t cause a punch off the line problem though. It sure sounds like a carb problem. Did you pull the air cleaner and try it without it? There could be a restriction problem there. Very puzzling!

 

I have run it with the stock air cleaner, with a chrome air filter and open element, and with nothing and it still stumbles.

Off the line on the primaries only, it's good! Put the pedal halfway down and she lurches! No tire chirp though.

I'm running the stock mechanical pump and a holley fuel pressure regulator set to 6psi when running. Sure helps after I shut it off to not have fuel pushing past my needles/seats and flooding it!

I have tried all 3 accelerator pump settings. I am currently on the middle hole. I noticed no change when changing holes. I also tried a .101 main jet and stock rod combo, and also noted no real change in acceleration or performance.

 

Also when I installed my new water pump and timing chain a week ago, I did check to see if TDC on the balancer was really TDC.

Put the balancer on, lined the 0* mark up with the timing indicator on the timing cover and checked the dizzy rotor position. It's dead on. Balancer at TDC, dizzy rotor pointed at #1 on the cap.