First post!! and a question.......

[Oliver Knuf]

You can get your 170 horses with a good done 2,4l (103mm x 71mm) together and even more with a bigger combination. 48mm intakes together with a 38mm to 40mm exhaust in good ported heads, a cam at around 295-300° and a c/r of 9:1 is all you need, besides a pair of 44mm IDF's and a good flowing exhaust system. If you take a 78mm or 80mm crank into that combo, you will go up to 15-20HP more, go with 48mm carbs and over the 300° durations, you'll receive even more. You see, there's no real need for NOS and btw, a combo in 103mm x 71mm is even cheaper than any other 78mm x 96mm! If money plays no role, go even bigger with the crank, then you've got it. If reliability is a thing for you, Use a 78-84mm crank to 96mm bore combo, but then with excellent build-on goodies.

At least, we've got 2l street engines (high compression, high duration) done here, that reach the 165-170HP, too. Our Cup engine produced slightly above 180HP, with a 74mm x 92mm combo and loads of goodies. That engine runned in several races and was just overhauled one time a year. Top HP was reached at 6900rpm.