360 vs 383
LOL! OK, so no knowledge about something not on the internet. We'll just use NHRA factored hp numbers for Stock and Super Stock competition. "68" 383 330 hp and "74" 360 245 hp. Look it up.
I did and you're 100% wrong. Those are the "advertised" HP#s, not NHRA factored hp/weight. While I was at it, I looked up my old '68 Coronet 440/383 4bbl car specifically and the HP was 290 with OE heads and 295 with aftermarket ones. The minimum weight for that car is 3,416 lbs which is being generous.
If you want to prove these ideas to yourself, go to
Wallace Calculators which are digital versions of the Moroso slide rule calculators that all the cool racers used way back when. So find the 1/4 mile stats calculator and input the 3,416 lb. minimum weight and then 290 hp and it spits out an ET of 13.49 @ 100.2 mph. Sounds pretty good for a decent running 383 with headers and slicks. Probably puts you down in U/stock with the 6 cylinder cars though.
From there however, you can input different numbers to see what class you might be able to run in competitively. Say you want to run in SS/IA with the '71 'Cuda I mentioned in one of my prior posts. To cover the SS/IA index of 10.70 in a '68 Coronet at that 3,416 lb. weight, it would take 750hp to go 9.66. Sounds fun! Who's paying?
I think we'd all like to know how to get at least 750hp out of a stock stroke 383 with OE or equivalent stock port/runner/valve sized aluminum heads (a difference of 5 hp) and a 625cfm Carter AFB. I'm all ears. No biggie for you though right 66fs, you got all the good parts laying around already because 383s rule and 360s drool. A few nights after work in the garage and a couple Sunday's worth of T'N'Ts and you're there, right?
I will couch that by saying that scenario obviously holds true for all engines in class racing including the more competitive ones. It's also why the shops that build class engines are some of the best out there. They understand the task and can make it happen within the restrictive parameters a particular combo might be saddled with. Yes, it's tough to do and takes a lot of time and money to sort those things out. Some guys are at it for years and are still off the mark because it's so difficult. To be sure though, none of that know how is based on fuzzy memories from 50 years ago either. But I digress.
Sorry to get too far off topic but whether "I was there back in the day" or not is irrelevant - facts are facts regardless of whether we understood them 50 years ago or now.
nhra disagrees with you
383 dart 296 hp factor
383 road runner 300 hp factor
360 from the 70s 300 301 305 nhra hp factor
https://www.nhraracer.com/content/general.asp?articleid=69161&zoneid=132
Ha, beat me to it.