Performance work turns out to be very similar to restoration work. The following list really isn't complete and accurate. I really don't want to know exactly how much this whole thing cost. What you have here is a rough idea about the cost. Remember, different things are going to be added, or subtracted, if you actually do this work on your Corvette. The interesting thing is that the cylinder heads, which was the purpose of this whole odyssey, represent very little of the actual cost. I actually paid more for the intake manifold than I did for the used cylinder heads. We won't even discuss what the completed cylinder heads cost. Also, look at the simple fact that half the total cost was labor.
When you're all done with this job, you've spent more than your Corvette is worth. The wholesale value on an '85 Corvette is $5000 if you're lucky. We spent that much, and a little more, by the time we finished. On the other hand, I lost a lot more than this over the past year in tech stocks, so why bother counting? The real problem is explaining to the family why you just spent over $8,000 on a $5,000 Corvette.
The real-world figure for performance, once you get past the bolt-on stuff, is going to be between $75 and $100 per horsepower. For instance, Vinci Performance sells a package for the C5 Corvette. It adds just over 100 bhp to your C5. It'll also cost you about $10,000.
You can look up just about any of the performance packages on the Internet and check out what horsepower costs. Keep in mind that the actual total bill, installed, will be more than the Internet price. You'll quickly see that about a $1,000 per horsepower is what serious power is going to cost.
All of these numbers actually make the bolt-on stuff look like a real bargain. Everyone laughs at the airfoils that fit into the throttle bodies, but they actually give you two or three horsepower at a cost of just around $60. Throttle bodies are another item that's a real bargain. Vinci Performance sells a polymer throttle body for the C5 Corvette that will give you about 8 hp for $129. This figures out to just over $16 per horsepower, assuming you install it yourself.
If you're looking for power per dollar, then you seriously need to look at some bolt-on items.
If you want real knock-you-back-in-the-seat power then you better start looking at the balance on your Visa card. When you put this whole deal on a cost basis, we see some real bargains.
For instance, a really strong ARCA or BUSCH motor will be around $55,000. This means you're only spending about $65 to $75 per horsepower. It's really cheaper to call Hendricks Motorsports and have a motor dropped at your doorstep than it is to have your local shop modify your current engine. Then again, the Hendricks motor would have a stupid carburetor on top.
I'm really not into retro power all that much.