0401 H/O
Titan Response
Engine shootouts such as the latest Battle of the Titans never fail to aggravate someone, and this one did not disappoint. However, I would like to point out one major discrepancy that I ran across while reading all the installments of this battle. In the Sept. '04 issue regarding the Ford buildup, I thought it odd that the compression ratio was nowhere to be found. Both the Chevy and Mopar specs were given.
I work on the Federal Mogul technical hotline specializing in chassis and brakes, but I have access to all the same information as our underhood guys have who sit right across from me. Needless to say, I couldn't help doing a little homework and figuring out the Ford compression ratio. I was able to come up with a range of 9.5 to 9.7 compression for the Ford. There is a major difference between 9.5 and 10.4 or even 10:1.
I have personally built a 351W with 10.25:1 compression and iron heads that ran on pump gas with less duration than your cam. It had power disc brakes and I drove it everyday. Your combo could have definitely used more compression to give it more of a chance. Up the 351W's compression and let the chips fall where they may.
Enough ranting. In the future, please use specs that are closer to each other or have more of a guideline so that you can see each combination's true colors.
Matt Housewright
Wellston, MO
We agree with you Matt, along with the dozens of other readers who wrote in about the discrepancy in the cam timing figures for the Ford. You're also right on the money with the Ford's compression at 9.5:1. We received so much mail from the Ford faithful that we are going to shave the heads and bolt in a Crane cam that more closely matches the other two engines so the Ford gets its day in the sun. It should make for interesting reading, especially if the Ford ends up making more power!
HP Hoopla
I just read Jeff Smith's article on rear-wheel horsepower numbers in the latest CC ("The Brutal Truth," Nov. '04). It's a good look at the new phenomenon of RWHP figures and how to improve them, but it's a bit misleading if someone is looking for actual in-car performance increases.
Trying to convert RWHP figures into concrete acceleration data from a dragstrip is pointless. Improving RWHP figures of a given combo is very useful as a tuning tool, but comparing it to another car is meaningless. Telling someone to swap their "inefficient" high stall equipped auto trans for a manual will get them a significant increase in rear-wheel performance but will more than likely cost them a few tenths at the track.
Take, for example, Doug Kelley's '69 Road Runner in the same issue ("Midwestern 'Tweeners"). Swap out his 4,500-stall TCI trans for a four-speed and he has a 400-plus rear-wheel-horsepower car instead of the 364 quoted in the article. He also would probably end up with a 12-second car that mph's well instead of the mid-11-second machine it is now. Hell, turbo rice rockets routinely dyno 350-plus RWHP in much lighter bodies with lighter driveline components but can't match Kelley's dragstrip performance.
I've heard the Turbo 350 versus Turbo 400 debate as to the increased horsepower consumption of the larger trans, but in the real world, ask anyone who has upgraded after blowing their TH350 and the TH400 runs just as quick. Even though it is heavier and theoretically more "inefficient," on a higher-horsepower car the loss is so small as to be insignificant and well worth the reliability of the TH400.
All in all, it was a good, informative article and certainly relevant today with all the chassis dyno shops and the popularity of dyno contests. It's just that rear-wheel dyno tuning is just that, a tuning device and not a great predictor of real point-a-to-point-b performance.
Tom Scala
Warren, OH