Back in the day, an Airman at Nellis AFB was fixing a blown head gasket in a Chebbie Vega. The feeler gauge/straight edge test said it was just outside tolerance for warpage. He took a GIANT Mill Smooth flat file and "trued" the head with it. It worked but it wasn't the most elegant fix. Not something I would recommend anyone do. A big Mill Smooth flat file is useful to set on the head and carefully "dress" the surface. Hugh spots would get shiny and low spots would not show any change in appearance. This is just a light pass or two, just to clean the surface. We aren't taking off any real amount of material.

If the gasket looked good and no discoloring was noted on the head/block mating surface, I would be concerned it has a cracked head or block. I've never had a hard time with a Ford six not sealing, even if it was just beyond warpage specs. Back in the day when I was a young broke-@$$ Air Force sgt, we would get a Fel-Pro gasket set and coat the gasket both sides with silver spray paint meant for Barden Bumpers. Let it set up to a not-tacky state, put it together. These new gaskets that come with a funky coating on both sides seem to work real well for difficult situations, better than silver paint anyway.

Too bad you're not near someone that could magnaflux the head for cracks & check for warpage. More likely the head is badly warped or it's cracked.

Let us know what you find.

 

It appears that the coolant in the #6 cylinder was just from lifting the head off as the two main cooling passages for the head are at the back of the engine right in back of #6. Was a very tiny amount. #4 was definitely the leak though as it was pressurising the radiator. There doesn't seem to be any damage at all to the gasket whatsoever the coating they put on from the factory is still very much in tact everywhere on it. There used to be a couple machine/engine shops around me as a buddy of mine down the road(he runs a 400hp 300 in his 30's coupe stock car) had his work done at one of em. But they all went the way of the dodo as nobody nowadays needs machine/engine work done as most people just get a new car when something needing machine work happens. I'll have to ask him where he gets his work done now as he still runs it.

 

So remember how I said that I had the feeling of "one step forward two steps back"? Well the second step back just came. When going over the cylinder head and the gasket to make sure all the ports were matching up i noticed a good size crack in the area just about the exhaust valve seat. Even worse was that it wasn't the only crack. There were three cracks total, one in #2, one in #4, and one in #5. The two other cracks were much smaller but noticeable nonetheless. It's very strange as they weren't there when i put the head back on as i would've noticed them when working the bowls. But as soon as we fired it up it wasn't running on #4 as soon as it fired. So I gotta find a new head now.

 

new , as in brand new heads seem to be on the menu over at ford six.
soon we may well see a very substantial choice in power heads.

carburetors; don't overlook the autolite 102.

if you can find one, a fish carb will send u to the doc. with whiplash self induced ano a permagrin on ur mug.

I wonder how well that FI cam will run with a carb.
most of your troublessings will vaporize with a physically smaller carb.
primary. placement is very important.

 

My troubles weren't with the carb, the carb was just fine, and the engine was running just fine with it(seemed to like it very much indeed ) The troubles are that the P.O. didn't change or even remotely care to check/change fluids with the truck. The coolant was mostly water(in a cast iron block, cast iron head engine (water+cast iron=rust) And as such the heater hoses look like caves with stalagtites and stalagmites all throught, and the radiator was coated inside with red/dark schmoo. The coolant passages in the block and head were all plugged up where the two met which probably lead to it overheating(which it would do if you weren't watching it even in normal light driving) The engine was overheated at least once in its life with it's P.O. as these cracks were not caused by me as i never overheated it and monitored the temperature pretty much constantly. So it isn't the carb that's the problem, it's the lack of maintenance done by the P.O. thats the problem. I need to get a new head because of it. The engine really seemed to like the carb. The throttle response was instant and crisp even from idle to half throttle(that was around 5,000rpm as it was in neutral) much improved over the stock limit of 4,300rpm. Now i know that that is negligeable as there's no power at that rpm but the fact that it can actually get there now is an indicator that it's breathing and running more to it's potential. Do i think that 600cfm is probably a little too much for an otherwise stock 300? Yes. But do I regret the choice I made in carbs? Not one bit. The engine will get some performance upgrades down the road (hypereutectic pistons, Crane 503901 cam, metal cam gear, HV oil pump...etc) but for now the vacuum secondaries will only supply fuel as needed in addition to the primaries. For right now though i do have bigger issues than the carb and cfm i chose to use such as finding a new head for my engine. Scrapyards/boneyards are few and far between near me, but I'll be calling around tomorrow to see what i can dig up. No sarcasm/ill will/negative words just saying, the carb definitely isn't the problem or even a problem at all lol.

 

all true and of course I defer to ur choices.
my observation is limited to the physical size of the carb and the limitations associated with the larger bodied carbs.

 

Yes there are some things that could've been easier with a smaller bodied carb. I will conceed that point, but I definitely think that this carb was worth the little headaches it presented. So onto more pressing matters. My father located a head for the engine, unfortunately they sent the wrong head. They said this head was for a 95 300. The one they sent was for a pre '85 300. Stud mounted rockers, 70cc chambers...etc all together wrong head. So getting it back to them come monday for the right head will hopefully bring a good useable head. These efi heads are known to be prone to cracking especially if overheated even once depending on the circumstances. Nothing to do but wait and see. Been a while since last posted an update, but the hunt for a head has been a very rough one. Will update when a useable head is obtained.

 

Alright, so the yard says they have the right head on the way and it will be here tomorrow just have to give them the wrong one in exchange. So progress will begin again when the head arrives tomorrow. Hopefully this one will be an efi one in better shape than the carbed head. When tomorrow comes we shall see.

 

Well the guy coming from the yard to make the switch today was a no show, so have to wait until tomorrow to get the head. There's that one step forward two steps back feeling again......

 

Alright! The yard finally came through and I now have a hopefully good head. Tomorrow will be putting the head back on and bolting everything back up for it's first actual successful all cylinder firing run. The exhaust is just about done, it's a 3" single inlet dual 2.50" outlet Flowmaster 40 muffler with aluminized exhaust from the original mufflers location back with dual tips coming out the rear under the bumper. Fuel system is done and ready to go, fuel pressure is set for 6psi to the carb and everything else sent back to the tank via the return line.The truck should be done and on the road (murphy's law prevailing) if everything goes well. Update to come tomorrow should be around afternoon time, by then we should be up and running. At least this time i'll have someone to help me lifting the head in and holding the manifolds while torquing em down. It's the little things

 

So the engine is all buttoned up and it runs sooooooooo good oh my goodness...... It runs about 1000rpm for fast idle then the choke opens up and it drops down to about 650-700rpm for base idle. The exhaust makes it sound like a 60's high compression lopey v8 mixed with a cummins diesel. It sounds super nice. There's still a couple of problems to fix, the fuel system is not working correctly. The pressure takes about three key cycles to build up to 6psi regulated pressure, once the engine starts the pressure drops and bounces between 2-4psi then after about 30-60 seconds it drops to 0psi then about 2-5 minutes later the carb bowls empty down past the sight glasses and the engine sputters and dies. Running the screw all the way in or out does nothing to bring up the pressure. I will be calling Holley tomorrow to see what they can tell me. The engine is running on all cylinders and it sounds very healthy, no sag, no lag, just crisp smooth power. I do have a question about wiring though, the P.O had taken out the pipe for the coolant temp sensor on the water neck and just put a pipe fitting and cap in its place. The A/C never worked, the compressor never kicked on. I put a new pipe and sensor on and the compressor kicked on and was blowing cold. In my wiring mess i accidentally cut the two wires for the sensor pigtail out and can't figure out where they went, the compressor isn't kicking on and the air is blowing only out of the defroster vents. Am I missing something here? Why would the coolant temp sensor be working with the A/C system?

 

Calling Holley tech support lead me to the conclusion that my pressure regulator isn't up to snuff and is failing under the pressure. So i'm in the process of getting the 12-881 switched out for the more expensive 12-880 regulator. The first Holley tech I talked to said it should work fine, now i'm told by both another Holley tech and a Summit tech that it is way too much pressure for the reg.......hmmmmmm Well it'll get switched out and hopefully the fuel issue should be resolved.

 

Not being a carburetor fan, I've been staying out of it, but you have just struck what I think is the big problem with these changeovers.

How exactly do you deal with that high pressure EFI fuel system?

I think the current advice you are getting is accurate. There just is too much pressure to deal with. So, I'd like to suggest an alternative. Your truck is a 96, so, it will be using the FDM's which use a high pressure, in tank pump. The factory EFI system uses a bypass regulator with a return line to keep the injector pressure somewhere in the 40 to 50 lb range, but I think those pumps can deadhead up to about 100 lb. The earlier trucks, 1990 and down used a frame rail mounted high pressure pump and lift pumps in the tank which provided somewhere around 15 lb. pressure which worked the tank switch in the dual function reservoir and fed the high pressure pump on the frame rail. What I think would work is to swap out the in tank FDM's for the 87 to 90 in tank pumps. You would have to use the plumbing and the dual function reservoir from the older system should you be using both tanks. You would not need the frame mounted pump and you could use a bypass style regulator to bring the pressure down to carburetor levels, dumping the bypass fuel back down the return line. There still is the matter of controlling the in tank pumps, but I would look to the 460 application for a circuit that can handle this. Don't just wire them to an ignition feed!

 

This was one of the biggest hurdles I knew i would have to go through in the changeover. There were a couple of ways I thought of going about this. 1.Was to drop the two tanks and take the pumps out, replace them with hard lines into the tank, run rubber lines to the frame with a FV1 selector valve then to a jigger pump(tops out at 7psi) up to the carb. 2. Was to do what i did, and keep all the hard lines, pumps and switches...ect and put a different pressure regulator in place to bring the 45-60psi down to 5-6psi. The regulator I got I was told by Holley that it would work for my application, and it does, until I fire the engine up. I found a better one, one that is made for this application. A Mallory 29387 regulator. Made for high pressure fuel pumps inlet(maxes at 70psi), and regulates down to 3-12. Its $120 but it makes everything much simpler fabrication wise. Don't have to drop tanks, or run new lines, circuits, switches...etc. Just plumb it in before the carb, set it and forget it. Keeping the fuel injection would've been cheaper short term but it wasn't winning an contests fuel wise, and it was just annoying seeing all that mess Ford made under the hood. Vacuum hoses and wires strung every which way, intake going up and over the valve cover, just lots of unnecessary clutter. Not knocking Fuel Injection one bit, it's got its perks, it's got its place, I personally didn't like how Ford did theirs and a different F.I setup would've been thousands. Unless i went Clifford/Offy intake and T.B.I but that's a down grade fuel distribution wise. I understand so is the 4bbl, but it is a more efficient and better intake, with more room to breath the engine is supposed to get better mpg and pull better. S.P.F.I is still going to outperform my setup by quite a bit as it has better fuel distribution, but that's a fully custom setup that costs much more than mine. Besides, I think it looks super nice seeing that 4bbl, air cleaner and manifold under the hood. I'm getting the new regulator probably about Monday. So that should just about have it running, just gotta finish exhaust work, make a throttle bracket, and run the choke wire, set base timing, tune the carb a little bit, then we should be done on a bun.Sometime I think it would've been easier to drop the tanks and run new hoses with new lower pressure pumps, like you suggested, but then i look at what i would've had to do and what i've done to get the same outcome and I just grunt and wish it was done. Lol
.

 

There are a lot of people who have gone the same route as me with a pressure regulator for a efi to carb swap, but there aren't a whole lot of regulators that can do the job as I found out the hard way. Aeromotive makes a couple but they're over $200 for theirs, Holley has one about the same price as the Mallory but they only sell it with -6AN port threading. There are also others who have done as you said and changed out the pumps and ran new soft lines. Others did none of the above and either already had or drilled out the mounting boss for the mechanical fuel pump. The high pressure pumps for the efi systems are a very tough challenge to work around. Either you shell out and don't have to do a lot of work dropping tanks, wiring, running new lines, or you don't shell out and do all that. Either way you end up with a working system it's just what grief do you want to go through? Grief of paying out, or grief of extra work. Now on any given day I would choose the extra work over shelling out, cause savings right? Well this time along with the input from my knowledgeable family members in the auto world, they said I should go this route. As i'm still climbing the ropes I went with their suggestion. I think the Fuel Injection system Ford put on these engines could've been routed/attached much better, but my head was on borrowed time unbeknownst to me, and along with a whole list of reasons, I chose this path. Many people who have completed the same swap i'm doing have reported that their fuel mileage rose substantially from the stock efi system. Usually in the realm of 14-16hwy to 18-20hwy(sometimes 20+) and that sounds very nice to me. As when trying every trick in the book for mpg my truck never did better than 16 hwy with the bed empty A/C off and cruising 55mph@1200rpm in overdrive. Time will tell how this all ends, but until then, I did figure out why my A/C no longer functions. When I removed majority of the EFI wiring harness for underhood cleanliness and simplicity sake diagnosing any future problems, I removed the wires and pigtail for the coolant temperature sensor which the computer now reads as infinte resistance aka open, aka engine overheating so it won't engage the A/C system for fear of overheating the engine. Gotta place a resistor of correct resistance in line or just run a new wire to the sensor...... hmmmmmm decisions.....