What index will my 72 be in?

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423dak

423dak

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Building a 72 Dart Swinger with a 5.9l engine. I don't know much about the stock classes as I only bracket race. I do know that the car will fit in the crate motor class with the combo I have but how do you figure the index?
 
Your car should fall around G, H and I/CM with a 300hp Magnum crate motor. Maybe F/CM if shipping weight is light enough in the guide. Basically you can add or subtract weight to go up or down one class from the "natural" class it falls into. If I remember correctly, indexes are I = 12.15, H = 12.00, G = 11.85, F = 11.70.

IHRA has the HP factored to 325 on the 360/300 Magnum. My 360/300 Commando is factored to 320HP. The 360/380HP Magnum is defactored to 370, I believe. But it is still not a good combo in the faster classes & indexes it would run against.

You'll need to do a lot of research because it's harder than most people think to make a car in Stock run under the index.


I just double-checked the class indexes and they appear to have been lowered .05 for crate motor combos!

http://www.nitrojam.com/downloads/pdf/competition/stock_indexes.pdf
 
Thanks. Power to weight. Got it. Yes I did hear that a lot of the idexes have been changed. Not too worried what the car will run. They are doing a Stock/Super Stock series at the local tracks this summer and I thought it would be cool to get in on that. They do it on Saturday and then I would bracket race on Sunday. Just more seat time.
 
Glad to help. But 2 things I'd like to be sure you're aware of:

1) The horsepower ratings used to determine the class based on the sanctioning body posted shipping weights are the numbers "assigned" to the particular engine you have, not the "advertised" #.

2) When you determine your particular class in Crate Motor Stock, it has to be able to run at least as fast as the index for the class. In other words, the index is a minimum performance requirement. If you are faster than the index, you can dial faster. If you can't run the index, you will be dialed-in at the index, not any slower.

Good luck!
 
you have to dial index even if you are not running the same class car?
 
the slowest you can dial is the class index...

if the index is 12.00 and you can only run 12.20...you will be dial in at the class index of 12.00...

if the class index is 12.00 and you can run 11.50...you can dial under the class index to match what you can run...

if you race a car in the same class...the first car to the finish line wins...no break out.
 
bracket racing is so much easier! I have a lot to learn The best way to do that is to dive in! Thanks guys.
 
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