What is a 470?
Simply put, a 470 BBB is the cubic inches we ended up with, when machining the crank and bores to fit the most advantages parts available. It was just dumb luck that we ended up with a cool-
4.350 bore, 3.95 Stroke are the specs.
Two Challenges present themselves when building a Buick 455 for Performance. A brief discussion of these issues will help you understand why we build a 470 Buick.
Genesis of the issue:
Buick 455 pistons in the aftermarket today all are more or less "Blueprint spec" pistons. When the Buick engineers designed the engine, the created a set of specifications for the engine, one of which was compression distance on the piston. Virtually all Aftermarket pistons on the market now are based on that spec.
The problem with that is the fact that the stock piston was designed to be .030 to .040 below the deck surface of the block. This allowed for production variance in sizing, on everything from the crank, rods , pistons ... to the block itself. Pistons sticking out of the bores would be the death on the assembly line, so that could not happen. Hence the very conservative CD of the stock piston.
Nearly all aftermarket pistons available for the 455 Buick, have a compression distance of 1.975 to 1.985.
Where we end up:
If we do the math, we see that to reach 10.570, which is the deck height of the 455 Buick, we need a piston that has a compression distance of 2.02. If we were working with an NOS block, we would want a piston with a CD of 2.02. In normal rebuild situations, we have found that it takes a .020 cut to perfectly square and clean up the deck of the block, so with stock crank and rods, we would want a piston with a 2" CD in a rebuild situation, to produce a zero deck clearance.
What what happens when you use "inexpensive" pistons
To use previously available forged pistons, and achieve the preferred zero deck clearance, it is common to have to machine .040-
Why you should care about this
Your new Performance engine is the most efficient, the least prone to detonation, and the most powerful when the pistons are level with the surface of the cylinder block. This is know as "zero deck clearance", and is universally accepted in the performance aftermarket to be the most desirable situation. Why would you settle for less? We can accommodate special requirements for both CD and dish volume if the situation required it, for a small extra fee. We also can build zero deck pistons for stock rod/crank 400/430/455 Buicks, in any bore size required, without the full custom price.
Knowledge is Power
Even if you don't buy Pistons from TSP, and build a 470, you should understand the issue. Call your machinist and ask him how much he will charge you to cut .055 off the decks of your block. Most often, you will find that you could spend that money on the right pistons, and have better parts, instead of using it to support your machine shop. Your machinist won't mind, the last thing he wants to do is cut .055 off a block.
Stock Buick Rods -
For stock use, the Buick 455 connecting rod is plenty rugged, and the reason not to use them, even for moderate performance use, has little to do with durability. The problem with stock rods is that they are hard to work with-
• Factory bolts don't dowel the cap in place-
• Enter ARP Rod bolts-
• And finally, after you get past that hurdle-
It was not at all uncommon to have $300+ in a set of nice, prepped stock rods. And they are more susceptible to failure in a high performance engine that a good HD aftermarket rod.
The 470 combo
This combo is not new, we certainly did not "come up with it" at TSP. In fact, there were several builders who had built 470ci engines. The deal is pretty simple-
The problem was in the past, the custom pistons cost around 1K, so no cost savings were realized.
What had to happen is that 40 pistons had to be purchased from Diamond racing pistons, and with that buy-
Here are the specifics:
The stock Buick 400/430/455 crank pin has to be offset ground .050, which reduces it to 2.200, and increases the stroke from 3.9 to 3.95. It is also widened to 2". This allows the aftermarket BBC rod, and the BBC rod bearing to be used. Now we have a multitude of rods available. I chose the 6.800 inch length, as the longer rod reduces stress on the cylinder walls. Rod costs range from mid $400's to just over 1K, depending on the manufacturer you select to provided them. Rod bearing choices are excellent, and cost considerably less than what is offered for the Buick. Billet steel, Forged Steel H and I beam, Aluminum and I would imagine even Titanium rods are available. Finally, you can pay attention to the BBC section of your catalog for something!
The custom piston we created is from Diamond Racing Pistons in Michigan, and is an exclusive part created for us and sold only buy us. We do sell these pistons outright, it is not required to by an engine from us to get this piston.
The piston is exactly right to fit into a block that is decked .020. It goes in with no modifications to the rods, and the bore size is the desirable 4.350. It's 1.775 CD, a 6.800 long rod, and the .050 stroked crank, combine to produce the desirable "0" deck clearnace, without the need to re-
Our pistons feature:
Designed to zero deck your shortblock with just a .020 clean up cut on the block (10.550 deck height)
25cc spherical dish-
extra deep .300 x 15* symmetrical valve reliefs
.030 offset pins for quiet operation cold, with the .0045 piston to wall clearance recommended.
Standard duty Pins and Spirial locks included
Pin fitted and ready to go
Change any spec to customize your pistons, for just $8 per change/per piston. Up to 2 changes allowed-