467-Ratman

I was running some numbers on my 467 motor with the Desktop Dyno and the HP and torque seems high, my engine has merlin iron heads, 310cc intake runners with 119cc combustion chambers, 2.25 intake 1.88 exhaust. Crane cam, 296-2, Keith black pistons, 9.1-1 compression, Holley 780 dual feed carb, GM aluminum dual plane intake, large tube headers with flowmasters. The cam has 236 and 246 duration @ .050-lift and lift is 550 intake and 571 exhaust. My hp numbers: 540 @6000rpm and torque: 511@5000rpm. Does this seem right? Thanks for the feedback.

Clink69

Seems a little high to me , would expect closer to 500 HP.

:flag

mountainmotor

Just guessing 470-480 max.It is one point of compression and 20 degrees of duration shy of making 520- 550 with a 850 carb

Flareside

Just make sure you have the valve "test diameter" and "pressure drop" as well as the flow numbers entered correctly and it's supposed to be reasonably close on HP numbers. I don't like the fact that is never shows a low end improvement when changing from rect. to oval heads. It doesn't seem to take into account port velocity. In that program, bigger is always better!

BeaterShark

I have compared it to at least 5 different Chevy High Performance buildups and have found that nowhere on the graph did it differ by more than 5%. Remember also, that CHP does their testing on an engine dyno with no accessaries or fan. I'm not even sure if they have the water pump?

Do you have a roller cam? In the Dyno2000 user's guide, it states that for mild roller cams (ie street cams), the "solid" cam type better models the performance.

jamesah

Is there a deom version of this software?

467-Ratman

My cam is a Crane PowerMax hydraulic, 296-2, duration 296 and 306 with 553 lift and 571lift. The Merlin heads are supposed to flow a ton a air, but at the expense of torque at low rpm. But it should not make much difference with the big cubes, 467!

bence13_33

In my opinion (which doesn't count for much) I would:

A) Bump the compression up to at least 10:1

B) Switch to an 850 Carburetor...that 780 is TOO SMALL. Remember you have to feed those extra cubic inches.

C) Get rid of that cam and go solid flat tappet or hydraulic roller

There, in a nutshell, is where your performance can be greatly improved. Those are just my thoughts.


[Modified by bence13_33, 8:00 PM 2/6/2002]

467-Ratman

I am somewhat concerned about bumping the compression to 10+ :1 or higher with the crappy gas we have. I don't want to be searching for 98+ octane to keep it running right. I would like to use Sunoco 94, what do you guys think about changing the compression? Thanks for all the suggestions, I do appreciate everybodys 2 cents worth!!!

mountainmotor

Tom,
Forum member ddn's build up is very close to what you need.I am helping him and your motor should be close to 600hp on pump gas with out being too radical on the street.A quick trip to the Eleven second 1/4 mile with good street manors and all the low end you can ever use with the use of Rectangular port heads.ddn's heads are Oval port but will still go the 11's.Email me if interested in the specifics.


[Modified by mountainmotor, 6:27 AM 2/7/2002]

MotorHead

92 octane should be good enough for 10:1 CR :D