There is your problem, and why its gutless on top.

 

Why I asked.

 

That cam is not doing you any favors, it's a low performance low RPM cam with lazy lobe profiles and a wide LSA. No good if you want power or economy. Look at the Comp XE or XE 4x4 line. I run a Comp 34-235-4 in my 460 and it makes a ton of torque at all RPM, great for towing and can hold 65-70 MPH in either 4th or 5th depending on the grade with my fairly light 5000 lbs give or take load.

You need to get your cam timing sorted as has been mentioned, you have a low performance and low RPM cam that you installed advanced, which lowers the usable RPM range.

What pistons and heads are you using?
Piston to deck clearance?
Any port work on the heads?
Headers or logs?

At the least we're looking at a cam change and getting cam timing right. Depending on what's inside you may need to change pistons (or heads) to increase compression. Stock these smog era 460s were around 8:1. 97cc chambers in D3VE and E6TE heads, factory grand chasm pistons with at least 22cc dish, a huge detonation prone .040" piston to deck clearance. These things need fixed if they were not addressed in the rebuild.

You also mentioned stumbling when giving more throttle under load. This could be from leaning out. Have you verified secondaries are opening and jetted rich enough? Increased primary jet size? Plug chop after this condition? Is timing fully advanced under these conditions? What is total mechanical advance? More advance may help if you don't get into detonation. Also, too much total advance can cause stumbling or poor performance as well. For a low compression engine with smog heads I'd be starting at 10* initial and 34*-36* total.

In short, depending on your goals you may be able to get away with a cam that better suits the engine and your goals, cam timing straight up, rejetting, good timing curve. Getting the rest proper won't fix a poor bottom end build and mismatched heads though. Depending on the bottom end you might be able to band aid the bottom end issues with early small chamber heads. Head porting on the exhaust side is pretty much mandatory if you want decent power or economy out of factory iron 460 heads.

Diesel is not the answer unless that is what you prefer. My IDI with turbo and higher output pump does not pull a load as well as my 460 truck and is not nearly as fast unloaded. If you want to make an IDI perform well it gets very expensive, far more expensive that getting the same performance out of a 460. A Powerstroke would be even more expensive and if you don't trust a simple reliable mechanical diesel, you certainly won't trust a fancy expensive EFI diesel with many more points of failure.

 

How does his cam compare to the stock camshaft? Can he get away with just pulling the front off and resetting the cam sprocket?

While my goals were not set very high, I have never been disappointed with a free flowing exhaust, 4bbl intake and 4bbl carb, with the stock camshaft. I have even swapped pistons out on some engines for higher compression, and kept the stock camshaft.

 

I don't know the specs on the cam Ford used in the 80s. This one is likely not much better. If I had numbers on that and specs for the rest of the build I could put it through desktop dyno to get an idea of what it's doing.

With iron heads, especially unported, you need a split duration with an appreciably longer exhaust duration and fast ramp rates to maximize the flow through the valve while it's open. Even just a real simple cleanup of the smog humps in the exhaust ports gives an appreciable improvement. These heads just don't flow well on the exhaust side as cast. Porting is critical.

Honestly if it were my engine and I was pulling the timing cover to get the cam set straight up I'd swap to a more appropriate cam, it's not much more work at that point and will give big gains.

 

I have never tried pulling one of those cams in the truck, but I envision having to pull the radiator and possibly the A/C condenser? And then you have to pull the valve covers, pull the carb and intake, pull the rockers off pull out the pushrods and hope you can get the lifters out. Since this engine has been rebuilt not too long ago, pulling the lifters may not be too bad but it can be a pain on a engine will high miles.

I think it would be quicker and a lot less work to pull the fan shroud, waterpump and accessories, pull the damper, timing cover, and reset the cam gear.

 

Obviously less total work is faster, but that doesn't address the OP's issue of an engine that does not deliver the performance he requires. It's not much more work to pull the radiator, grille and intake. Consider that vs living with a terrible performing engine (that likely gets poor MPG) for a decade or more. Short term pain for long term gain.

Regarding lifters, I'd never had trouble getting lifters out of any engine unless the cam was not broke in properly.

 

I have a terrible time when the lifters get that brown varnish on the bottom side and don't want to come up through the lifter bore.

 

Cans of carb cleaner and the tool for removing lifters and out they come.
Dave ----

 

Thank you all very much for your input. For right now on my small budget I'm going to use the kiss method and just reset the cam timing. In the future I will look into changing the heads and cam to better suit my needs. I do have a set of heads from a 71 429, pretty sure they aren't much better than what's currently installed but I could have them rebuilt and maybe a port/polish.