some of you may or maynot know.. the Dynojet run of my 400 was significantly down from what was expected (actually, its about what I expected, just not what it should be) . Specifically, 319 at the tires.
All cyls were hitting normally and plugs looked slightly lean.. but did not get the chance to rejet b4 the "experts" stripped the screws on my demon mainbody for the rear carb bowl.

Even going up from 88s in back to about 92-94 would have probably only gained about 10-15hp. I am now about to the point of pulling it back out and putting it on an engine dyno.

This is the process I was going to have them go through if the engine dyno results come back low..


Cylinder Leakdown (maybe done b4 the dyno)
CC combustion chamber (should b about 10.8 to 1
Remove head and flow a couple of ports (should be 265 at .6)
check cam intake centerline
check cam on cam analyzer..

Any comments?

 

I don't know your setup.
On mine with that big of engine you need a big exhaust with no restrictions. I picked up a half second by replacing my y-pipe with a better one. This was with headers and 3inch cat-back already.

 

should be enough airflow for 500+hp.

Track1 heads
CNC-vic Jr
Demon 1000
Cam-motion hydroller with .596 intake - .603 exhaust and 240ish duration.

 

Dayum!!! You are WAY off from where you should be...

My 400, stock bottom end except for pistons, double-hump heads with 1.94" valves, Comp XE274H cam, stock L69 air cleaner, Edelbrock TES... did 284 RWHP and 373 RW ft.lbs. Yours should spank mine like a red-headed stepchild.

What kind of air cleaner setup do you have? What exhaust?

You should be easily able to get 500 RWHP + out of that long block if the induction and peripherals are right.

I think you're wasting your time checking compression; if it was so bad that it was costing you 250 crank HP, you'd have oil everywhere from crankcase pressure, maybe even be blowing front seals out and stuff like that.

The cam checks would be a great idea. Or, just try a different cam, some off-the-shelf one or something.

That's alot of compression; what kind of fuel was in it? What's your total timing like?

 

the headers are hooker supercomps.
They drop down to 3" head pipes around the trans and that goes into the http://www.mufflex-performance.com/

Motor has about 30hours on it (its got an hour meter). And I really was pretty happy with it just being runing for the longest.. but it never has really pinned you back in the seat. Revs quick.. but not much else.


Had a performer rpm (spacer with portmatch intakes) but was not much different. The previous 400 (last spring-summer) did have a comp magnum (more or less off the shelf) with the same heads and it did not really seem much differnt either. quick rpm ,, thats all.

Aircleaner was an ebrock off the shelf job.. but the element was a new fram.. its also got a cowl hood so heat should not be a problem. Starts and runs fine.. just nothing else.



Never really has smoked.. a very light puff when lifting off after runs or on startup..

Last time I ran a compression test, they were all over 200.

I was going to check it again (once I get the carb fixed ) but the timing should be 15 inital and about 21-22 in the distributor. I use about 30percent 100 octane racegas with 92pump.

Well.. and actually,, all cammotion cams, come with a cam-analyzer printout.. and from what it provided, intake centerline should be right.