[disclaimer start]
These are typical newbie questions, and I appologize in advance, since I know these questions are so basic and have been answered time and time again.
I also know this is in threads all over the place, but I can't find a good answer in my (short) searches...
[disclaimer end]

So here goes:

My 1967 Merc 250 4x4 has a 66 428. It currently has a worn out holley 600 (or 650, can't tell/haven't checked).

The truck has only owned me for a month, so I don't have all the details on the motor sorted out yet. From seat of the pants, there's some cam in it (based on the idle). It has a cast-iron manifold on it, headers and big-ish dual exhaust.

On 91 octane it pings at wot, so I had the timing set back two degress to 30/10 (if I remember correctly). Sop says I should put the timing back to what it was and just run 94 octane (wallet says 'ouch').

When the carb is working ok (sporadically) it has tons of power and gets 12+ *canadian* mpg (remember my gallons are bigger than your gallons!!!).

My mechanic tells me I could go with a bit bigger carb, possibly the 750 edelbrock performer. I'm worrried about over carb-ing the motor though.

Questions :
Is there a stamp on the intake to tell me which one it is? If I can figure out what intake it is, does anyone have info on carb choices?
Should I swap out the intake, maybe put on the edelbrock performer 390?

Thanks,

darrell

 

Wow, we can't even buy 94 octane here in California, not a regular gas station anyway. 91 tops. I would go with a 750 cfm carb on a modern aluminum intake. That cast iron piece weighs almost as much as the motor. To fully realize your 428's potential, if your wallet would allow it, I would also throw on a set of Edelbrock's Performer FE heads.

 

Stock 428 carb is 735 CFM

 

So, I'm going out on a limb here, and going to suggest that I could go to a 750 on the stock intake without overwhelming the intake.
For the short term I like this, since it means I don't have to change the intake right now, just replace my worn out carby and continue on...

darrell

 

Darrell, Before you jump headlong into something that might not be the answer, you may need to find another mechanic that has experience with older carb engines. Unless that truck has 10-12 to 1 compression the engine should run on reg. gas. The dizzy may be a tooth off, the timing chain stretched. IMHO

Keep digging on what you have.




John

 

428 4V as installed in 1966/67 Galaxie/LTD & Thunderbird // 1966 Mercury Montclair/Monterey:

Compression: 10:5-1 / 360 HP @ 5400 RPM / Holley 4V.

1967 Mercury Monterey/Montclair & 1968/70 all (except CJ): Motorcraft 4V.

1966/67 "Police Cruiser" 428 has a different cam then the above 428's, solid lifters, aluminum 4V intake manifold.

 

Problem is since it's NOT stock you would need to find out what cam and if it has stock type pistons as well as if the heads have been shaved etc to determine where you REALLY are on compression.

 

I had the intake manifold gasket replaced a couple of weeks ago by a licensed mechanic (it was draining oil onto my driveway). He's a respected ford guy, and finished his apprenticeship long before the age of electronic 'gee-whiz' control systems -- he's good with points and a carby.
I'm pretty confident that the distributor is lined up, since he had it out to get the manifold off. Also, when the truck runs right (intermittently) it runs *really* right.

It ran fine before and after the intake manifold gasket as well.

So without getting too bogged down in details about cam lobe size and duration, and knowing that I need 91 octane gas, and knowing that from the factory this 428 probably came with a 735 cfm carb, I'm going to go forward with the 750...

Thanks for all the input, this is great!
darrell

 

Darrell,

Where in Canada do you hail from?

I have a 600 cfm on my 410 (which is more or less a 428) in my 69 F100 4x4. I too am thinking about going up in carb, but I also think I'll go to a more aggressive cam at the same time (don't have the numbers handy, but it is referred to as an RV cam).

If you go to a new intake, do not waste your money on the 390 performer, get the RPM as the 390 performer is more or less the same casting as a stock 360/390 intake. The RPM has more flow.

I am currently running a 390 GT intake that has been port matched to the heads, which are ported and polished. Other than saving some weight I don't think the RPM intake would do more for me than the one I have.

 

By the way, you should post some pictures, sounds like you have the makings of a bad *** truck. What does it have for steering and brakes?

 

I'm in North Saanich, BC (just out side of Sidney, just outside of Victoria, BC).

I've had rv cams in other trucks (chevy 350's, before I came over to the good side). I was never all that impressed with them. I guess there was some mild improvement, but sop didn't excite me.

I was looking at the performer 390 vs the rpm because of the posted 'usable rpm range -- idle to 5500 vs 1500 to 6500. My 428 has great usable power right down to idle. I didn't really want to loose that. Maybe I should look further. Either way I think I'm going to hold off on the intake for now anyhow. Having just spent the money to get the stock one sealed back on, I hate to just have it removed and throw that money away...

I'll post some pics. The funny thing about hunting for this truck is that I searched all over canada and western us (the web is a wonderful thing), and found the truck about half a click from my house.

darrell

 

Seeing as how this is an intermittent thing that is going on, I would take a look at the point setting and the dwell and make sure it is set where it should be. Points will cause the symptoms you are describing. It could be as simply as a point adjustment.

 

I was googling information of some heads - I was thinking about buying a 390 crank, heads, pistons and rods to redo my 360 into a 390. The head numbers were a bit odd and I couldn't find any info, so I widened my search criteria to "Ford FE" and found the 410 for sale in Airdrie - pretty much my back yard.

 

Darryl, Lots of guys come in here and start post about a problem, and we don't have a clue what the experience level of the person working on it is. So it was a general statement.

You run your truck on 100+ octane if it makes you happy, but it should run on much less.

Have fun doing it your way.




John

 

Hey, jowilker, no offense taken, I totally appreciate the input from the forum. I wouldn't be posting questions if I thought I knew everything -- I'm a newbie to the fe world, but have some (backyard) background in knuckle scraping and swearing (how come I always wind up bleeding when I have a wrench in my hand????). I'm try to gel together the ideas and opinions presented and make the best possible decisions.

I've done the basic stuff to try to diagnose the sporadic poor running -- plugs, points, condenser, rotor, cap. The wires look pretty new (and not melted onto the headers!); the coil is shiny (ie: I have no idea if it's working properly or not). After that, I have to hand it off to a mechanic for the tough stuff.

Yesterday and today it ran like a dream, so I guess I've got to wait until it acts up again.

yellowtruck, its got arm-strong steering, manual brakes, the 4-gear, 4.56 gears, dana 60 rear, dana 44 front, dana 24 in the middle. I'm never going to need to go to the gym again. I get a workout every time I pull into a parking lot!

Again, thanks to everyone who has weighed-in, I really appreciate the input...