I was wondering if anyone could run a desktop dyno to find my simulated HP and Torque at the flywheel?

My engine is a 1979 ford 400 CI
it is bored 0.060 over
hydraulic lifters
stock exhaust manifolds, dual 2.5" exhaust
Edelbrock 400 perofrmer intake
cam specs are:
ADV. DUR. 260 INT, 270 EXH
.050 DUR 204 INT 214 EXH
CAM LIFT Int .280 , Exh .295
Valve Lift Int .484 Exh .510
Lobe CTRS INT 107 , Exh 117

I have 2 carbs now, and i would like to see which would be better, the first is an Edelbrock 1407, a 750 CFM manual choke, The other is a 1406 Edelbrock...I believe this is a 600 CFM? electric choke.
If someone has the time to run this with the different carbs, it would be greatly appreciated..

---JOHN

 

OK, I have been out of town. I will do it tomorrow.

 

Thank you...I'm just curious how in depth my engine builder went with the rebuild, but, it sounds like it was just a normal rebuild to me so far..I appreciate you taking the time to run this for me.

---JOHN

 

John,

I got 193hp@3000rpms and 360ftlbs@2000. I might be off a little on the camshaft math, maybe danlee will give you some better news.

There is no significant difference in numbers between your two carbs. I would go with the electric choke 600. A set of headers would help you out some.

Sanders

 

I got 385 ft-lbs torque@2000 RPM, and peak torque 388 ft-lbs@3000 RPM. The torque drops off a cliff after 3K RPM. The peak HP is 247@4000 RPM. This was with the 600 CFM carb. The 750 CFM carb does improve things slightly, but the improvement doesn't justify the loss in fuel mileage and drivability.

You should add headers. The headers bring the torque to 442@2000 RPM and 382@4000 RPM. The peak HP is 291@4000 RPM.

I simulated it with a stock replacement dished piston and got 8.43:1 CR, and no porting work on the head or milling or decking done to the head or block. Let me know if any of this work has been done or if a different piston was used.

 

Thank you both for running it, i was mainly curious about the peak torque, but seeing as how it is around 3000 rpm, and it drops off drasticly after that...is not too encouraging. The heads were milled down to flat again...resurfaced? but i am not sure how much was taken off of them. Also, the pistons are dished, .060 oversize ofcourse, not sure of the cc or the cr on them though. Looks like it would be beneficial for me to buy headers though...but ive heard they dont like to fit right, and they develope leaks easily...any merit to that? Now i just have to find the formula for HP loss at higher altitudes, and get an idea of what it might be closer to up here, at 9000 feet... Thanks again for running this....

---JOHN

 

I have found that if you cut the header flange between each tube, that it cures most leaks. I have had to use this trick a few times. A set of CHI aftermarket heads wouldn't hurt either.

Sanders

 

Just found out that it DOES have flat top pistons. Im planning on buying hedders ASAP, cause i have a chance to show it off some over the Labor Day Weekend, so that might be my next project here.

---JOHN

 

The CR is 9.15:1 with a flattop piston. The torque with headers is 456 ft-lbs @ 2000 RPM, and 445 ft-lbs@3000 RPM. The torque is still 431 ft-lbs @ 3500 RPM. The peak HP is 303@4000 RPM.

 

Thanks again Danlee


---JOHN

 

I run a 400 with fenderwell headers, bowl port work, 3" to 2 1/2 Flowmasters, dual plane Offy intake,roller rockers,4.10 front gears/4.11 rear gears, 3000 stall converter. I have used a 600, 650, 750, and a 830 on it. My cam is a bit wilder than yours high speed towing vs yours being more of a low speed towing. Between the 600 and 830 there was only about 1 MPG differance unless you got happy feet which is easy to do with the power this combo puts out. Currently I am building a carb out of a 600 holley with a 750 throttle plate. Only issue is the push rods, a little too much RPM and they bend or break. We figure my HP to be aroud 360 to 370 with the current heads. The original heads were ported for HP from a 72 351C Mustang and produced closer to 400 HP. Enough to push the truck to near 140.

 

Thanks Turbo! That is good info. Obviously if I can get this carb & system dialed in with the correct jets & timing, she'll run like she should.

 

I think I modified my distributor to 8 degrees mechanical advance 16 total and inital advance to 20 giving me a total of 36 degrees. I have changed inital advance between 18 and 22 degrees depending on the gas I am running and load I might be hauling etc... I disconected the vacuum advance because with out EGR its difficult to reap any benift without over advancing

 

I now have a holley 650 Double Pumper on it, and it feels like it has gained alot of power. I put 33" tires all around now instead of the 31" tires, and it still runs the same ET at the track. I am thinking of getting a nitrous kit from a friend, and giving it a 75 or 100 horse shot to try out....and then putting the nitrous kit on one of my other prjects....Any reasons the nitrous would be bad for it? It will be a small shot, and only used a few times...

Also, can anyone dyno the engine with the holley now?


It can spin both rear wheels with a non-posi...non-locking rear now in denver, quite easily ( wouldnt do it with the edelbrock and the 31's), and i suprised a honda sunday when racing him, he ended up using nitrous to try to catch me, then i heard a nitrous boom, and he coasted into a parking lot...One less import on the roads atleast...

My engine guy also did the angle valve grind...or whatever its called to the heads...i cant remember right off hand, but its supposed to improve flow. He was really adamate about not porting or polishing the 400 heads. Still no hedders, ill likely get them within a month now.

Thanks..

--John

 

DD2K does not distinguish between an Edelbrock and a Holley. I will see a small improvement going from 600 CFM to 650 CFM. The Multi-angle valve job will help the flow. You never polish the intake ports, and the intake ports do not need porting. Some cleanup in the bowl area and some porting/polishing of the exhaust port should be beneficial.