hey ed, i'm not trying to start anything with you about the rpm's. but i have dynoed hundreds if not thuosands of big blocks that dont make power anywere near 7500+ rpm's. i guess i'm a little confused on what your saying. are you saying build all big blocks to rev over this rpm's? are you saying all engines worse rpms are 6600-6900 no matter what cam profile or valve train is in it?
Hi,
No problem. I can not understand why you have not seen max horsepower rpm at any higher ranges unless you are dynoing them on Chassi dynos.
No matter what engine we are talking about for drag racing even a Vw Bug engine or a low rpm 430 Lincoln engine the same principles do apply. Rev beyond maximum Horsepower rpm so the rpm into the next gear will not be too far below the torque peak rpm. Inthe older days and actually even now in class racing it is very helpful to reach maximum hp rpm quite a ways before the finish line traps, for ET but for mph you want to reach max hp rpm right in the last beam. So you gear and tire accordingly.
The information about the rpm of most harm for a BB Chevy came from a very good and trusted reliable source that has worked all of his life in researching engine valve train issues and how to avoid them. His name is Noel Manton. Currently he is closely working with more than one NHRA Pro Stock teams, Brad Anderson's operation from time to time as a friend and professionally with one of the top Blown Top Alcohol Teams that is running today. When the 454 was popular in the different sizes and on the way up to the bigger engines he studied them and tested continously to learn how to get more li9fe from them.
Second Source of info about this is David Reher. On the Reher Morrison webpage is a bunch of technical articles that were first published in National Dragster.
Obviously if the engine is not built for it and the components are not designed for it, the higher rpm will not help much and could even hurt. I would think though that in the year of 2007 that everyone racing would at least be as far up to steam as we were back in the early 1970's.
In the early days I had no ability or capability of using any dyno services, most others didn't either. We did however have the capability of seeing how fast and how quick our cars were at the track, just like we all have today. It is by function of trying so many different approaches and different shift rpms that we learned where our cars worked the best.
In todays world, the only engines I have been priviledged to get dynoed were Big Big Blocks. By that I am meaning of 572 cu in to 738 cu in versions. I have not seen one of even those that max horsepowered at below 7,000 rpm. My typical 615 cu in to 646 cu in will max horsepower at 7,400 rpm to 7,600 rpm. This of course does depend on several different variables. With those max hp rpms that is meaning that if run as all motor they would want shift points of 8,000 rpm or higher. I know for a fact that the new not revealed engine of one of the top Pro Mods to be installed toward the end of the year is making hp all the way up to 8,000 rpm and that one is 880 cu in.
Maybe I was over revving my old 460 cu in engine way back in 1984 but it still put down slightly above 1,000 hp way back then. That is not dyno hp. That is hp by calculations of 154 mph in a car weighing with driver 2,980 lbs.
If your BB Chevys are maxing hp at lower than 7,000 rpm, I will be happy to talk with you and hopefully be some help. 972-633-0563.
Ed