I'd say that sums it all up..."Bottom Line"...it's all Big Corporations care about, and let's face it, $800/unit per hundreds of thousands of units per year, is quite substantial...
And the differences in power or reliability seem negligible between the OHV and OHC, so where's the big incentive to change???

Nice discussion btw, very entertaining..

 

In the interest of trying to keep this Forum "above" what often takes place in others (as I know this is the wish of the folks that run the Forum), I'll do my best to do this in a "matter-of-fact" manner. Sorry to those that wish for more entertainment. I'll gladly go have some more fun in a more appropriate Forum - IMHO, I'm showing a LOT of restraint here. Please.....make my day.

Ditto.

On the same dyno, with the same operator, using the same procedures, I disagree. It should be noted that you CANNOT accurately compare results from the same car on different dynos.

Awesome. And what data did this produce to support the 15% "rule of thumb" that you have stated?

I contend that you do not have such data - nor have I seen it here. It requires that one has access to both an engine and chassis dyno, and comparison runs are made with no changes. I've seen some data like this (specifically from a fellow racer, Robin Lawrence, who also runs the NMRA series) - though haven't done the testing myself.

Don't know. Further, as I can show repeatability within less than 1%, I don't believe it matters in the context of this discussion.

I only know the very basics of the design differences (weight of gearing, rail design, minor issues like that), and thus I am also not qualified to accurately discuss it. However, as many of my fellow racers who have done similar testing know, there is a 10-15 RWHP difference between the trannies mentioned above. That is easily enough to vary the 15% "rule" by 3-4% one way or the other.

Thanks for the tip.

Cool. Could you please state your credentials? Do you test-n-tune, bracket race, class race, what? Do you use the dyno to tune, to baseline, to find the effects of mods, what?

Ditto, but not the point of this discussion, nor is is relevant.

Good for you.

Good for you x2.

I wish you the best of luck. Kindly tell us the results when you have them.

I am not a professional either, though I would love to be.

Irrelevant to the conversation at hand.

I've never been on 'Speed'. ESPN2.

Thanks.

No, that was not the question. Kindly go back and read my first response. There was nothing there about someone having 40 more HP in my class. It was about a blanket statement you made that 40 hp would make all the difference. That is simply incorrect, and I have provided documented, verifiable data to back up my assertion. You have provided....words. Folks can draw their own conclusions.

It should be obvious now that you telling me to "shut up" is quite useless.

See above.

Good day.

Fast LS1...just a note about being "under-square". The engine builder that did my 4.6 has a 97 Cobra with a stock bore (.020 over) 5.4 DOHC. He routinely spins it to ~8000 rpm, and has yet to experience a rod, bearing, or piston failure related to that rpm. The car runs 10.2x @ 134+ mph at 3350 lbs, N/A. 4.56 gear on a 26x10 slick if you would like to do the rpm vs mph math.

The engine is really quite mild, idles at ~900 rpm (cams are ~.520 lift and .230 duration), and keeping in mind that it needs to be fed 110 octane race gas, is very streetable. It makes in excess of 500 RWHP SAE (I don't have a link to a dyno run for that one - sorry). Regardless, I think that runs a bit counter to the idea that something being "under-square" cannot turn a respectable RPM.

BTW, so that those that wish to look it up can do so, the guy's name is Al Papitto, and he posts regularly on many of the Mustang Forums. He is a former IDBA Pro Stock bike champion, and up until very recently, built P/S bike motors (Suzuki) for many P/S racers. IE...he knows his stuff.

 

Bob--

What CR was/is that Cobra running (your engine builder)?