i did a motor build something like the impersonator build that was in the chevyhighperformance mag
its a 400 with a .040 over bore and i used 11:1 compressioni ues a compcams 240/246 @.050 and .507/510 lift and a.f.r. heads 195cc with r.p.m air gap intake 800c.f.m. edelbrock carb 1.5 headers with 3 inch exhaust
but when i put the numbers in the desktop dyno i get alot less power that they tested with the impersonator  
i would think with that set up i would make over 500hp 525tq at least
what do you think ??  

Don't worry about your desktop dyno numbers. For that matter, don't worry about horsepower numbers. There just numbers from a design tool, worry about the performance of the vehicle. Or if it's not a drag car, worry about how it drives on the street.  

well what do you think my 1/4 mile times would be with this set up ?
it will be a street /strip car and i did put alot of time and money in to it and i would hate to see it under perform
and i was just wondering if there is anything i could change to make it better b4 i take it out  

I guess you will know if it underperforms when you take it to the dragstrip...

I can say that a Edelbrock carb will NOT make the power that a modular carb can. Also, I hope you have a typo about using "1.5" headers.  

no they are 1 1/2 headman headers with a 3 inch collector and i have a 3inch system as well
i am also changing my intake to a rpm air gap (i had a performer air gap on it ) but would a victor be better with the flow i need ? it will be a street /strip car
as for a carb what is a modular carb ? like a holley or somthing ?  

Those headers will be awfully restrictive. You have a lot of cylinder head there, I would go with 2" primaries.

Yes, a Holley or a Demon will make more power than an Edelbrock carb.  

I have the AFR 190 cc heads on a 383 with a RPM intake, Comp roller cam ( 230/236 @ .050), 1 3/4" headers and 3.42 gears. In a 3600lb. TA I got 12.6 @ 107 my first time out at the track with it. Your heads should make some good torque between 4000 and 5000 RPM. The RPM AirGap would most likely work better than a single plan intake. Torque is what moves the car down the track. You should have lots with the extra cubic inches you have. Unless you plan on doing alot of high Reving I wouldn't go with 2" headers. I can shift at 5500 and still get a 12.7 and not hurt the motor.  

Want to see something interesting on the desktop dyno? If it's similar to the dyno program I use (Dyno 2000) mess around with the header and exhaust specs.
I changed my small primary headers and muffler specs to a large primary open header and the hp numbers go through the roof. In the dyno cell they're (probably) using a optimally spec'd header including properly sized (diameter and length) secondary. If makes a huge differance to have exhaust tuned to the rpm range in which the engine is being tested.
And yes, the Holley or Demon carb will make more power than the Edelbrock especially if they have more cfm. Remember, this is computer dyno stuff and you can move and remove to get all kinds of different results. Try messing with the cam advance and see what that does.
I've taken my little 350 with vortec heads and a 268h cam and improved it by nearly 100hp just by moving around the specs I'm taking about.
I wish it were that easy to make the changes in the car!  

well i have been checking my headers more i bought them 5 years ago so i dont have the box  but on the sale slip it has the part number and it is a 1.5 header number
but i just bought a set of 1.5 flowtech for my truck and the tube are really small for the flowtech so maybe i got 1 5/8 on the monte the pipe size should not make a diffrence from company to company right ? 1.5 is 1.5
so i may have luck after all i think that they are 1 5/8  

Remember that when you install your headers pay attention to how the collectors(secondaries) are blended into the exhaust pipe. It's important to size the collector LENGTH with respect to the operating engine RPM. A LOT of builders ignore this part of header design and end up leaving lots of available torque on the table. It's well established that secondary size and length are as or even more important than primary size or length. That's part of the reason dyno numbers are often much better than installed numbers.  

i am running my motor with 32 degrees timing right now is that good or should i put more or less ?  

From what I understand, it largely depends on the cylinder heads you're using. A head like the vortec or similar 'fast burn' heads require less total timing to achieve the best results.  Dyno testing shows that 34 degrees total timing makes the best power with these heads although you have to remember that there are a lot of variables which will contribute to what the engine needs. I haven't researched the AFR 195 specifically but I do know that they are excellent heads.
If you've duplicated the impersonator, then their dyno results should give you a pretty good idea of what's needed.
Typical Chevy distributors will have about 20 to 22 degrees of mechanical advance built in. That means that any more than 12 to 14 degrees initial will put you at the maximum tolerable for a typically driven street engine. The books say to start with smaller amounts of initial advance, say around 6 to 8 degrees and then make small increases until detonation is audible. Back it off a bit from there and you should be good. Overall, if you have a fairly straightforward combination then 32 degrees won't hurt anything.