I have a early 70s 400 in my D-100 2wd short bed, the engine was stock when i got it, I put an edelbrock single plane intake, 750 dual feed holley, Mallory dist, headers, mopar purple shaft cam 292*adv dur 248*dur @ .050 .509 int lift .509 exh lift, adjustable rockers, 2500 stall convertor, 3.73 gears with a richmond locker.I talked to the guy i got the truck from and he told me all that stuff should work with a stock bottom end and stock heads. I cant get it to run well enough to fine tune it, can someone give me an idea of what jets sould be in the carb and where the timing and advance should be. I was told the idle will have to be around 8 to 900 because of the intake and the size of the cam. Thanks in advance for any help!

 

You probably are not running nearly enough initial advance, but you have some work ahead of you

The immediate trial would be to set the advance using a vacuum gauge just adjust it to "peak" for maximum vacuum, then retard so the vacuum drops about 2" vacuum

But you really should:

Check your timing marks so you KNOW they are correct, using a piston stop, which you can buy or make, like this:

http://www.jerrybramlett.net/images/...stallation.jpg

Pull no1 plug, turn the engine until no1 piston is "down a ways," then remove the battery ground and install the stop. Wrench the engine around until it stops against the device. Make a temporary mark on the balancer under TDC on the pointer tab. Do the same thing rotating CCW. Now you'll have TWO marks some distance apart. True TDC will be halfway in between, and if the original mark is accurate, that is where it will be.

Next, it is EXTREMELY helpful to "degree" the balancer, which you can easily do by carefully measuring around the balancer, then figure how many "degrees per inch". Use a flexible tape, NOT dividers, to measure your first mark. 40* works well, as you can carefully measure this with your tape, and mark it. THEN you can use dividers, to cut the 40 in half to make 20, in half again to make every 10, etc.

You can also buy timing tape from people like Summit for the correct diameter balancer.

Another thing that is probably "too late" at this point is "degreeing the cam" as the power band can be moved a ways by advancing/ retarding the cam, and factory tolerances definately affect this.

Next, you need to find out what sort of advance curve is "in" the distributor. You must be careful here, as some specs are printed in "distributor degrees" which are HALF what you see on the crank. An accepted "starting point" for a performance distributor is around 18-22* AT THE CRANK.

What this all means is that if you have the intitial timing set at around 15*, and 22 "in the distributor," this will give you an "all in" total advance of around 35-40*

Once you have the timing jacked in, start the car a few times to be sure it is not going to "kick back" at the starter. Once you get this settled in, NOW turn your attention to the carburetor.

Very first thing to do is measure idle vacuum, AFTER you have set the timing. Then find out what the power valve is in the carb. If the power valve is too high a number, it might be already opening AT IDLE.

IF this seems OK, then you can try to adjust the idle screws. In some cases, you have to screw with the carb to get the throttle plates "in the range" of what is called the idle transfer slots. Some guys drill holes in the throttle butterflies, and you can Google that, but many others advocate adjusting the secondary butterflies "stop screw" to crack open the secondary A TINY AMOUNT. Basically what this really does is to create a small air leak so that you can DECREASE the idle stop screw in the primaries and therefore move the primary butterflies towards "closed" and get the idle circuit working.

Frankly, for a low compression, heavy vehicle, and low speed stall, that cam sounds like it's way way too big. Depending on your tire size, those rear gears aren't all that low for a big heavy vehicle.

 

What gear ratio would you reccomend for it its a 2 wheel drive reg cab short bed, i think the rear tires are 28 inches tall but ill have to check

 

Depends on what you want to do with it According to an online calculator, 28" tires, 3.73 gives you 67 mph at 3000 RPM. That doesn't sound too bad to me, I as speculating that on a pickup you might have much larger tires. But the torque converter is certainly doing you no good with that big cam.

In my opinion, you need the modern day equivalent of the old 440 GTX cam. These were an EXCELLENT all around torque and performance cam with good street manners. We actually ran one when we put a 440 into a 74 Dodge 4x4 1/2T shortie back around 75

Nowadays, there are better cam designs.

 

I would think you would need 4.56 gears with 509 cam. Better off to change the cam..