445 dyno

[Barry_R]

Barry,

It is a Conical spring

Then the spring aint likely to be the issue based on past experience.

Kinda thinking like Jay - - ignition connection deal - or maybe some kind of shiznit got into the carb?

Snoop Dogg Rabotnick?

Sorry about that.  Couldn't help it.  Wind blew and my hat spun sideways....yo

[My427stang]

I have two theories on this one, of course all without being there, so it's all really a WAG

1 - It had a minor misfire or crossfire on top that fooled the O2 sensors into thinking it was fatter than it was, as you guys ended up with far less jet than I'd expect with a 780 and more timing than I'd expect it to need with that chamber indicating it was a little lean too.

2 - The carb wasn't opening all the way, even after you tied the linkage, which did something funky at the boosters that caused the abnormal jetting.  Building vacuum would indicate a carb size or throttle blade issue and could cause some puddling of fuel which made the mixture goofy and held power back

If neither of those are true, that lean of a jet could be an indicator of an HSAB issue that was making the booster come in too hard and too early, however, that alone wouldn't keep the power and RPM peak low, so I would go back to my evil theories

Too bad you guys couldn't have got a known good and BIG carb on it.  I don't think a 780 alone would kill the peaks on a 445, but it would have been good to see what it did with a known good carb and a little more airflow

[mn67]

Thanks Ross,

I will be playing with it a bit this week trying to figure it out. Until it is in the car or back on the dyno wich I am certainly up for I will not know how big a difference things make. I am pretty sure I can find most the HP of comperable builds but for the 70+  ft pounds of torque I am certain I would need to start over. For now I am going to optimize it as best I can and see what it does in the car. There are always more engines to build. 

[Barry_R]

I would think you might find another 20 horsepower in the package and maybe 15 or 20 more torque. Ain't no 70 pounds in there...

[blykins]

My guess is that there's a hidden 20-25 hp and 20-30 lb-ft there. 

If you're trying to match my 445 build where it showed over 550 lb-ft of torque, I would attribute that to the dyno.   I will say that the particular engine you're referencing put down over 500 lb-ft to the tires with a TKO and a 9" Ford, but chassis dynos are kinda like engine dynos...

[mn67]

I started this build looking for a solid 500/500 engine (just used the other engine as a reference) I know there is no where near that amount of tq in this. Anything above 500 is a bonus. But like all of us just want it to be as good as it can be. Thanks for your help, I will report back after I get it dialed in. In the end I am very happy with it, plus it sounds and looks great:)

[My427stang]

It's a great engine, and with traction will run hard.  My big thing is that I think it should peak at a higher RPM.  You won't get a big number increase like Barry and Brent said, but it just seems like for some reason itr an out of steam early

Can't wait to hear how it does!