How much dyno corrected HP?

[PRH]

What’s worked reasonably well for me is-
With the caveats that how good the “car” is(which is everything except the engine), is a huge factor………

If the dyno numbers are legit, and you’re racing at tracks that aren’t at high elevations(call it less than about 1000ft), in “reasonable” air conditions……… you should have the performance numbers from the Moroso S/P slider come within about 90% of the STP numbers from the dyno.

In extremely rare situations, with cars that are very efficient, running in great air, the numbers can be within a couple of percent.
In even rarer instances, the car can show numbers higher than the STP dyno numbers(off the top of my head, I can only think of one car where I have fist hand knowledge of the dyno results and the cars performance where this happens, and it happens pretty often with that combo).

The problem of not having reliable dyno data, is you’re guessing on two counts………
1- no known HP figures
2- without the dyno data you can’t really quantify how efficient the car is

With a unique engine combo like the OP has built, you could assume something around 750 STP hp would seem reasonable………. But so is 725, or 775.
That’s a 50hp swing.

 

[ValiantS]

Was this your 489 ci & what was rod length ?
That's a quality build

Thanks! It wound-up being 6.7ish based souly on the crank stroke and piston I had.

 

[ValiantS]

What’s worked reasonably well for me is-
With the caveats that how good the “car” is(which is everything except the engine), is a huge factor………

If the dyno numbers are legit, and you’re racing at tracks that aren’t at high elevations(call it less than about 1000ft), in “reasonable” air conditions……… you should have the performance numbers from the Moroso S/P slider come within about 90% of the STP numbers from the dyno.

In extremely rare situations, with cars that are very efficient, running in great air, the numbers can be within a couple of percent.
In even rarer instances, the car can show numbers higher than the STP dyno numbers(off the top of my head, I can only think of one car where I have fist hand knowledge of the dyno results and the cars performance where this happens, and it happens pretty often with that combo).

The problem of not having reliable dyno data, is you’re guessing on two counts………
1- no known HP figures
2- without the dyno data you can’t really quantify how efficient the car is

With a unique engine combo like the OP has built, you could assume something around 750 STP hp would seem reasonable………. But so is 725, or 775.
That’s a 50hp swing.

Thanks, this is ANOTHER reply I appreciate in noting there are many qualifiers. Would the motor make any more power with Holley carbs on a dyno? Separately, would the car be quicker with Holley's? Would the car be faster with a working hoodscoop and airpan? How good is the converter? Are the headers a good match? etc I put a windage try in it and I'm wondering if that isn't helping it's output as well. To give it some context, it's quicker/faster than a 512CID with higher compression, TF270 heads with a similar cam all done by a well-respected builder. (What HP you'd expect from this combo) All in a car that what I've been told is 275lbs lighter.