Machine Shop Services
Machine Shop Services
Pontiac V8 machine work done by people who build Pontiacs every day. Blocks, rotating assemblies, cylinder heads — measured, machined and documented, not just run through a machine and handed back.
Most shops can bore a block. Fewer know what a Pontiac block does when you bore it, which castings have the wall thickness to take it, and what the deck height needs to be for the pistons you actually bought. That is the difference here. Every job that comes through our shop is measured before it is cut and documented when it leaves, so whoever assembles the engine is working from real numbers instead of a factory manual written sixty years ago.
Currently accepting machine work only. We are not quoting new assembled engine builds at this time. For our fully assembled engines, see our Butler Built Crate Engines page for the latest builds, ready to ship. You are welcome to send your block or heads in for machine work, and we will help you or your builder put it together.
Get a free, fully customized, no obligation quote before sending your parts.
Cylinder Block
A Pontiac block that has been in a car for fifty years is not a known quantity. It has been hot, it has been apart, and somebody has probably already machined it once. Everything below starts from that assumption.
Cleaning, inspection and sonic testing
Nothing gets measured until it is clean. Blocks go through a three-step cleaning process — baked, blasted, and washed — then get inspected visually, magnafluxed for cracks, and sonic tested for cylinder wall thickness.
Sonic testing is the one that saves blocks. Published overbore figures are averages, and averages are how blocks get scrapped. Core shift in the original casting means two blocks with the same casting number can have very different wall thickness on the thrust side. A sonic check tells you what your block will take before a cutter touches it — not what the general run of that casting will take.
This matters most on the thinner castings and on any big-bore plan. If you are looking at a large overbore, have it sonic tested first. It costs a fraction of what a replacement block costs.
Services
- Wash and degrease block
- Burn and blast block
- Measure and inspect — bore size, main bore size, deck height
Align honing and align boring
The main bore is the foundation. If the mains are not straight and round, nothing you do downstream will save the bearings — and on an old block they frequently are not, because the block has relaxed, been apart, or had a cap spun.
Align honing brings the main bore back to true. Align boring is the step up when the bore has moved far enough that honing alone will not correct it, or when a cap has been replaced. A spun main is often invisible until the align hone starts to shine up the journals and the grooving shows.
Services
- Align hone — 2-bolt block
- Align hone — 4-bolt block
- Align bore to nominal bore size
Boring and honing — with a torque plate
We bore and hone with a torque plate installed. A cylinder that is perfectly round unbolted is not round once the head is torqued down; the plate simulates that load so the bore is round in the condition it actually runs in. Without it you are honing a shape the engine never sees, and the rings never fully seal.
The bore is cut to your pistons, not to a catalog number. Piston-to-wall clearance varies by alloy and by manufacturer, and the figure on your piston box wins over any published band. Send the pistons or the piston specification with the block, and the hone is finished to match the ring package the piston maker calls for.
Services
- Cylinder hone — deck plates, nominal size
- Cylinder hone — piston fit to deck plates
- Cylinder boring — .030″ to .060″+ depending on sonic testing
Decking and deburring
Square decking cuts both deck surfaces true to the crank centerline and to each other. That is what makes deck clearance a number you can predict instead of one you discover after assembly — and deck clearance is what sets your quench with a given head gasket.
Deburring is the step most shops skip. Casting flash, sharp edges around the oil passages and the bottoms of the bores all shed material into a fresh engine. Our full prep takes over a day on its own, including tapping every bolt hole and cleaning every oil galley, followed by a final jet wash and wipe down.
Services
- Deck block — cleanup cut
- Deck block — max .030″
- Deburr block — major surfaces and edges, oil passages, bottom of bores
Sleeving, cam bearings and stroker clearancing
A cylinder that has been bored past what it will take, or damaged, can be sleeved — one hole or all eight, installed and decked. It is also the route to putting a standard bore back in a block somebody already took too far.
Stroker clearancing is its own operation and it is not optional. A longer stroke swings the rods and the crank counterweights into parts of the block that were never in their way at 3.75″. We clearance the block for the assembly going into it, and the combination gets turned over by hand with a piston and rod installed to confirm it — every block is a little different because of factory casting variance, so this is checked, not assumed.
Services
- Install sleeves
- Install roller cam bearings
- Install and remove cam bearings — regular bearings
- Clearancing for stroker crankshaft assemblies
Rotating Assembly & Balancing
Most suppliers “box balance” — they balance to the weights the parts manufacturer published. We do not take anyone else's word for a weight on parts we stand behind. Every rotating assembly we sell, regardless of brand, is balanced in our shop by our own machinists.
- InspectionEvery part in the assembly goes through a multi-step inspection before anything is weighed.
- WeighingRods and pistons are weighed individually on gram scales — the actual parts, not the catalog figures.
- Pin fittingRods and pistons are pin fitted as needed so the assembly goes together the way it was measured.
- Computer balancingThe crankshaft is computer balanced to the rest of the assembly, so the counterweights match the parts that are actually bolted to them.
- DocumentationEvery weight and every figure is recorded on a balance card that ships with the assembly.
Sending us weights for a balance job
Our balancing system works from individual component weights — piston, pin, rings and locks, each weighed separately in grams — not from a single computed bob weight. If your machine shop has gram scales they can supply those figures. If all you have is a bob weight, get it to us and we will tell you what we can do with it. Anything you have purchased from us, we already have the weights on file.
Piston and Rod Work
Pin fit and rod bearing clearance are two of the measured items on a blueprinted engine, and both are easy to get wrong with the wrong equipment.
| Service | What it covers |
|---|---|
| Remove rods from pistons — press fit | Pressing apart a press-fit piston and rod without distorting the pin bore. |
| Remove rods from pistons — full floating | Separating a floating setup, locks removed and preserved. |
| Pin fit rods | Sizing the rod small end to the pin. |
| Pin fit pistons | Sizing the piston pin bore to the pin. |
| Rod bearing clearances | Clearances set to application. |
| Connecting rod reconditioning | Resizing the big end back to round and to size. |
A note on rods and spun bearings. If an engine spun a rod bearing, checking clearance alone will not tell you whether the rod is still usable — a big end can be out of round and still measure acceptable clearance at one point. The rods have to be checked for roundness. While you are there, pull the galley plugs and the cam bearings when the block is cleaned; debris left behind a galley plug will find a rod bearing again.
Cylinder Heads
Heads are where a Pontiac makes or loses its power, and where the most guesswork usually happens. Ours go through a documented process and leave with a build sheet recording every part used and every operation performed.
Valve jobs
Three-angle valve jobs cut on Serdi equipment — the same class of machine used in Formula One and top-level racing work — for precise seat and guide concentricity.
Porting
Hand porting and CNC porting, matched to what the rest of the combination can use. A head that flows more than the cam and the bore can exploit is money spent for nothing — tell us the whole combination and we will tell you where the ceiling is.
Flow testing
Tested on SuperFlow equipment, one intake and one exhaust port, so the number on your build sheet came off your heads rather than a catalog.
Guides and assembly
Guide installation — 16 guides installed and honed to size — plus disassembly, degreasing and reassembly with valves, springs, locks and retainers selected for your camshaft.
Milling heads — and what it does to your compression
Milling a Pontiac head is how you raise compression without changing pistons, and it is the step people most often guess at.
- .006″ of mill removes about 1cc of chamber volume. This is our measured figure, not the commonly quoted .005″ you will find online — and the difference adds up fast over a real cut.
- .080″ total is the working limit. We have gone to .100″, but beyond .080″ you are into questionable territory — core shift in the casting, and clearance between the valve and seat.
- That limit is cumulative. If a head has already been cut once, what is left is what you have. Ask before you plan a cut on used heads.
Final compression depends on your actual chamber volume, deck clearance and head gasket together. We pin it down once the parts are measured rather than quoting a ratio off a chart.
Head and intake services
- Mill cylinder heads
- Mill intake surfaces — with or without china wall
- CC chamber
- Add fuel injection bosses
- Disassemble heads and degrease · assemble heads
Why the intake side matters. Mill the heads and the intake manifold no longer fits the same way — the angle between the head and the manifold changes, and the intake has to be cut to match. If you are milling heads, plan on the intake surfaces at the same time.
What Gets Measured
A blueprinted engine is one where every figure below is a number somebody measured, not a number out of a factory book. This is the short version of what goes on a Butler Blueprint & Assembly build sheet.
| Measured | Gives you |
|---|---|
| Main journal & main bore, with bearings | Main oil clearance |
| Rod journal & rod bore, with bearings | Rod oil clearance |
| Crank endplay and rod side clearance | Thrust and oil throw-off |
| Cylinder bore & piston size | Piston-to-wall clearance |
| Piston pin fit | Piston/pin clearance |
| Ring end gap, top and second, each cylinder | Ring seal |
| Piston deck clearance with chosen gasket | Quench |
| Chamber cc + net dome cc | True compression ratio |
| Piston-to-valve clearance after degreeing the cam | Valve clearance, intake and exhaust |
| Valve lash / lifter preload, per lifter | Valvetrain setup |
Rod bores are always measured with the bolts torqued to final value. The bore changes shape when the cap clamps down, so a measurement taken loose is not a measurement.
Sending Work In
You can ship your block, heads and components to us, or bring them by the shop in Lawrenceburg. A few things make the job go faster and the result better:
Send the parts together
Block and pistons together, heads with their valvetrain. Bores are cut to your pistons and valve jobs are cut for your springs — parts machined in isolation get machined to an assumption.
Tell us the whole combination
Engine and year, block casting, bore and stroke, heads, cam, intended use and fuel. The right machine work depends on what the engine is for, not just what it is.
Say what has been done before
Previous overbore, previous decking, previously milled heads, a spun bearing, a replaced cap. What is left to work with depends entirely on what was already taken.
Talk to us first on big bores
If the plan involves a large overbore or an unfamiliar casting, call before you ship. A sonic test early is cheaper than a scrapped block later.
Machine work is quoted per job. Deposits are typically required before work begins — we will go over the specifics when we quote yours.
Tell us what you're building
Every Pontiac combination is a little different, and the right machine work follows the build. Call and talk it through with someone who does this every day.
866-762-7527
Butler Performance · 2786 Hwy 43 North, Lawrenceburg, TN
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