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GTX JOHN · 12-14-2020, 01:15 AM

Different Horsepower factors for similar engines in different year
cars.

My 73 400/Aluminum head = 296
Your 75 400/alum. head = 320

I/SA 12 LBs. per HP
Means your similar engine would have to weigh 290 Lbs
more than my car in the same class - An almost impossible
difference in weight to overcome give everything else is the same!

Much easier to change year of car when it is just grille/taillights
would give you a better factor or combo to work with!

The 78 318/230 is a great combo= we held the National Record and
many class wins including Indy before my son got bored with it and
decide to go faster!

The 78 360 started out at 270 and was a class winner and fast.
Eventually the Wagon was factored to 289 while the sedan was 270
making class impossible for us. Now all the 78 360 are at 289 with
either big cam or our old small cam version. The big cam is still
OK but no longer a killer combo.

Half the battle in Stock and Superstock is selecting the most competitive combo
out of some many possible choices.

12-14-2020, 01:15 AM	#7
GTX JOHN VIP Member Join Date: Jun 2009 Location: Boulder City, Nevada 89005 Posts: 2,719 Likes: 2,765 Liked 2,425 Times in 687 Posts	Re: Stock 1975 Dodge Coronet. Mopar guys. Different Horsepower factors for similar engines in different year cars. My 73 400/Aluminum head = 296 Your 75 400/alum. head = 320 I/SA 12 LBs. per HP Means your similar engine would have to weigh 290 Lbs more than my car in the same class - An almost impossible difference in weight to overcome give everything else is the same! Much easier to change year of car when it is just grille/taillights would give you a better factor or combo to work with! The 78 318/230 is a great combo= we held the National Record and many class wins including Indy before my son got bored with it and decide to go faster! The 78 360 started out at 270 and was a class winner and fast. Eventually the Wagon was factored to 289 while the sedan was 270 making class impossible for us. Now all the 78 360 are at 289 with either big cam or our old small cam version. The big cam is still OK but no longer a killer combo. Half the battle in Stock and Superstock is selecting the most competitive combo out of some many possible choices. __________________ John Irving 741 Stock 741 Super Stock Last edited by GTX JOHN; 12-14-2020 at 01:21 AM.