[Sirrotica]

Originally Posted by dmac

Then the job becomes more than a simple head swap. Dished pistons, new rings, more shop costs adds up for the average American making $30k per year. You may as well pay a couple hundred more and just buy KREs with the bigger chamber. Not having the bigger chamber cuts the potential market in half- not good for a company trying to break into the market.

I was building the engine from scratch, so dished pistons were the same as flat tops. The gist of the post is that it can be done if you want to run the cheaper, small chamber heads on a 455. Is it the cheapest route to aluminum round port heads, probably not, unless your building the engine in question as you are installing the aluminum heads, it can be done though. The post proceeding my post left the conclusion that there was no way to get to the end result of having a 455 with small chamber heads on it, my post said that the dished pistons were the way to solve the problem.

I'm thinking someone isn't just swapping heads onto a mostly stock short block and trying to run it as hard as they want to without something substantial under it. I'm more used to running on a dirt track, and if you just did a head swap on one of those engines without everything being top notch in the short block, in one night of racing you'd be picking the parts up off the track. I've tried it more than once, and that's the result. Cast pistons and tight clearances won't last when subjected to added strain, (more than squealing tires leaving the Dairy Queen) and higher power.

You may, or may not know, that Pontiac was more selective about parts and clearances when assembling round port engines at the factory. They weren't built the same as a station wagon 455 was, for a reason. The RA IV and the 455 SD also got forged pistons, the SD 455 with the long stroke also got forged rods, again for a reason.

The theory is that if they had the 87 cc heads available, you could pull a head swap and just not worry about the engine self destructing, until it happened...... Did the $30,000 a year guy save any money in the end?

[JLMounce]

Originally Posted by Sirrotica

I was building the engine from scratch, so dished pistons were the same as flat tops. The gist of the post is that it can be done if you want to run the cheaper, small chamber heads on a 455. Is it the cheapest route to aluminum round port heads, probably not, unless your building the engine in question as you are installing the aluminum heads, it can be done though. The post proceeding my post left the conclusion that there was no way to get to the end result of having a 455 with small chamber heads on it, my post said that the dished pistons were the way to solve the problem.

I'm thinking someone isn't just swapping heads onto a mostly stock short block and trying to run it as hard as they want to without something substantial under it. I'm more used to running on a dirt track, and if you just did a head swap on one of those engines without everything being top notch in the short block, in one night of racing you'd be picking the parts up off the track. I've tried it more than once, and that's the result. Cast pistons and tight clearances won't last when subjected to added strain, (more than squealing tires leaving the Dairy Queen) and higher power.

You may, or may not know, that Pontiac was more selective about parts and clearances when assembling round port engines at the factory. They weren't built the same as a station wagon 455 was, for a reason. The RA IV and the 455 SD also got forged pistons, the SD 455 with the long stroke also got forged rods, again for a reason.

The theory is that if they had the 87 cc heads available, you could pull a head swap and just not worry about the engine self destructing, until it happened...... Did the $30,000 a year guy save any money in the end?

Lol, I did exactly that. Threw a roller cam and some KRE D ports on my 455. Granted, it's not a bone stock build, it was built by a previous owner, but retains the factory rods and crank with TRW slugs.

I've been beating the crap out of this thing for a while now. I think this situation is probably a bit more prevalent though than having a bone stock 455 you yanked out of a wagon.

Dish pistons are certainly an option if you're building at the time of purchase. These speedmaster heads wouldn't have worked for me because I needed more chamber size.