Reply to "Yates Heads"

The compression alone makes the engine you reference an impractical street engine. With that kind of squeeze, and Yates heads on a Dart block, my guess is it would not be cammed accordingly either. If you did buy it, it’s doubtful that the short block would be useable as is. You likely would require different pistons as well.

I wouldn’t get too wrapped around the axle about the peak HP figure. It’s a pretty common misconception that leads toi a lot over over cammed and over carbed engine builds. I realize I’m about to start the whole thing all over again but strictly speaking, race engines make poor street engines and vice-versa. It’s an artful compromise for street performance. For the street, you need to consider many things including, reliability, required maintenance, required fuel, starting, idling, cost, etc. Few of the aforementioned are of much concern on purpose built race engines.

HP statements are merely a statement about that rate at which you’re making torque at a specific rpm. However, it rarely tells the whole story. But….everyone tends to compares peak HP figures and believe this means the engine will outperform others of lesser peak HP. For street cars and virtually every form of racing, maximizing the area under the torque curve in the rpm range you live will add up to harder acceleration and general performance. Drag racing usually can tolerate the narrowest rpm bands so peaky engines are the norm. IMO, the issue of reliability is a big driver and is a divergent parameter with power. Many people with the pocket book to put a race engine in a street car don’t have the skill or desire to maintain it like a race engine requires. Nascar engines don’t run in the same band as NHRA. That’s the difference between being built to live for 500 miles versus ¼ of a mile at a time.

From my perspective, street performance means 3000-6000 rpm. Will I ever see above or below that range? Of course. However, if you look at your tach during spirited street driving that covers a lot of ground. Some would bias my range up 500-1000 rpm or so but that’s all part of the compromise. With a 427 CI small block and hydraulic roller, I’m North of 500 ft-lbs at 3250 rpm, peak torque of 555 ft-lbs at 4750, and high 400’s at the top end of that rpm range. I’d have to go look at my dyno sheet (or retrieve my calculator) to tell you the HP but it will undoubtedly be well into the 500s and occur somewhere between peak torque and 6krpm. Will you win the Silver State with this engine? -Nope. But, for my money, any time you get a low maintenance (small block) street engine to give you North of 500 ft-lbs torque over that range, it’s bound to put a smile on your face. My 2 cents.

-Good luck with your build.

Kelly