McGonster Monster Motors LLC · Collinsville, Oklahoma · Est. 2026

Every Engine. One Network.

Free precision build tools for American iron — built by a working mechanic who got tired of guessing. Free tools. No paywalls. No BS.

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Tool network

twincamdyno.com predator212dyno.com 351clevelanddyno.com sbc350dyno.com m8dyno.com 454dyno.com

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Pick Your Engine

Every tool in the MMM network lets you build a full combination, see the dyno curve, and find the best price on the exact parts you just selected. All free. All built by someone who actually turns wrenches.

Harley-Davidson V-Twin

Twin Cam Dyno

Calibrated against Fuel Moto's published 103" shootout data. 31 cams, 14 heads, 12 induction options, full carb jetting for CV40, HSR42/45/48, S&S Super E/G, and EFI.

8 head castings with real lift-curve flow data. Holley primary/secondary jet recommendations, Edelbrock metering rod and step-up spring guidance, smart valve spring picker.

Predator 212 / GX200 Clone

Predator 212 Calculator

Full jetting for Mikuni VM22/26, PZ22/26, Tillotson HL, and Walbro — adjusted for your elevation and temperature. Rev limiter coil simulation, rocker arm pushrod calculator, smart spring picker.

Small block Chevy — the most-built engine in American history. Full cam, head, and induction combinations with real jetting recommendations.

Gen 1 M8 (2017–2023: 107/114/117). Cams, heads, big bore, throttle body, and tune — see the HP before you spend a dime.

Big block Chevy — build your 454 from the block up and see predicted HP and torque curves, calibrated against real dyno data.

From The Dyno

What The Numbers Actually Say

Every combination below was run through the tool on this site and written up with the full parts list and the dyno curve. These are the ones where the measured answer argues with what everybody repeats.

351 Cleveland — 351clevelanddyno.com

49 hp

The big 4V port gives up torque at every engine speed below 4,000 rpm to buy 49 horsepower at the top. On a flow bench the small 2V actually out-flows it until about .350″ of lift.

351C 2V vs 4V heads

2 points

Same ports, same valves, same flow numbers. The Australian 2V casting has a 58cc closed chamber where the American one is 75cc wide open — over two points of compression on identical pistons.

Aussie closed chamber vs US open

+40 lb-ft

at 2,000 rpm, and 83 more horsepower on top. That is the difference between a modern CNC head and an old big-port casting: the iron 4V trades bottom end for top end, the CHI just adds top end.

CHI 3V 225 vs stock iron 4V

3 lb-ft

is the entire spread between a 600 and a 750 below 4,500 rpm — and it favours the smaller carb. Everything the bigger one is worth arrives above that point.

Carb size — 600 or 750?

593 hp

Yes, a 351 will make five hundred with no stroker crank. The parts list is not subtle: CNC aluminium heads, a solid flat tappet at .629″ lift, and fuel the corner station does not sell.

500 hp with no stroker

349 hp

The only Cleveland Ford built with solid lifters, and famously soft below three thousand. That is not a fault — it is 58 degrees of overlap doing nothing at idle and everything at six grand.

1971 Boss 351

Chevrolet 350 — sbc350dyno.com

246 → 291

A dual-plane intake and a 600 cfm four-barrel, with the cam, heads, exhaust and ignition all left alone. The biggest single jump any bolt-on makes on a stock 350.

2-barrel vs 4-barrel

+47 lb-ft

at 2,500 rpm for the Thumpr, and twenty-one horsepower given away at the top for it. The lope comes from exhaust timing that deliberately hurts cylinder filling — you can hear it and you can measure it.

Comp XE284H vs Thumpr 279T

+7 hp

The nineties truck casting beats the sixties icon, and it wins at every engine speed in the table. It is also the cheaper of the two now that double-humps are collector items.

Vortec vs camel-hump heads

+34 lb-ft

at every single rpm, not just at the peak. That flatness is the signature of displacement, and it is why a stroker feels bigger than the peak horsepower number suggests.

350 vs 383, same top end

50 hp

between the smog-era iron casting the engine probably still wears and a modern CNC-ported aluminium head. Most of that is port and chamber shape, not the metal.

Iron vs aluminium heads

409 hp

Iron heads, pump fuel, no stroker crank and no power adder. This is the build most people should stop at — everything past it costs disproportionately more per horsepower.

How to build a 400 hp 350

Chevrolet 454 — 454dyno.com

0 wins

The rectangle port head does not beat the oval on a street 454. Not at the peak and not at any engine speed in the table, with the cam, intake, carburettor and exhaust all held identical.

Oval port vs rectangle port

+74 hp

for swapping truck peanut-port castings to early closed-chamber ovals. If you bought a 454 out of a truck or a motorhome this is the head you have, and it is the cheapest real horsepower on the platform.

Peanut port vs oval port

+50 lb-ft

and only nineteen horsepower, with the same heads, cam, intake, carb and headers on both. Displacement does not raise the ceiling — it fills in everything underneath it.

454 vs 496, same top end

−25 hp

is what the MUTHA Thumpr’s idle costs against the Comp grind beside it — despite being the physically larger camshaft on paper.

MUTHA Thumpr vs Comp XE284H

602 hp

on pump 93, with the factory bore and the factory stroke. No stroker crank, no big-bore block, no power adder. It is done entirely with cylinder head flow and valve lift.

600 hp with no stroker

+18 hp

from a straight bolt-in ratio change. The higher ratio multiplies the same lobe further, so you get more lift and more effective duration without touching the camshaft.

1.7 vs 1.8 rocker arms

Milwaukee-Eight — m8dyno.com

−3 hp

A 124 cubic inch big bore on standard heads, against a 107 with a cam and CNC porting. Seventeen more cubic inches and less peak power — the most expensive mistake available on this engine.

Big bore on stock heads

130 hp

at the rear wheel is what standard M8 rods and 107 flywheels are rated to hold. Bolt-on builds rarely reach it. Boost and nitrous walk straight through it, because they raise cylinder pressure rather than rpm.

The limit on stock rods

78 → 86

Exhaust, air cleaner and an ECM recalibration, with nothing internal touched. The gain is almost entirely the exhaust and the tune — the air cleaner contributes least of the three, which is the reverse of how they are sold.

What Stage 1 is worth

119 hp

Every performance part in the catalogue fitted to standard 107 cylinders, and the factory beehive springs still clear the cam. Past this figure the answer stops being parts and starts being cubic inches.

What stock cylinders will take

+7 hp

The largest single gain left once the bolt-ons are done, and the one people leave until last because the engine has to come apart to get it.

CNC heads vs stock castings

78 hp

at the rear wheel, exactly as it left Milwaukee. What holds it back is not the displacement — it is a cam that stops making useful power past 4,900 rpm and an exhaust built to pass a noise test.

Stock Milwaukee-Eight 107

Twin Cam — twincamdyno.com

+2 hp

The most common first modification on a Twin Cam and the one with the widest gap between expectation and result. The head pipe, the cam and the factory calibration are all still in place, and each one caps what a muffler can deliver.

What slip-ons actually add

4,700 rpm

is where the 551 runs out — a ceiling set by the camshaft, not by the engine. Peak horsepower on its own is badly misleading on this pair, which is why the delta table is the point of the page.

S&S 551 vs S&S 510

+6 lb-ft

flat across the whole range, with every part above the pistons identical. The only variable is the bore — 3.75″ against 3.875″ on the same 4-3/8″ stroke.

96 vs 103, same top end

102 hp

Triple digits at the rear wheel on stock displacement: a camshaft, ported heads, forged flat-tops and a matched tune. No big bore, no stroker crank, no power adder.

100 hp from a Twin Cam 103

55 hp

at the rear wheel, with the mildest cam Harley ever shipped in a Big Twin. The cam signs off before the engine has finished breathing, which is why a cam is the first thing that moves this motor.

Stock Twin Cam 88

121 hp

A 4.125″ bore on the stock stroke — the big-inch Twin Cam that needs no stroker crank, only cases machined to take the larger cylinders.

What a 117″ build makes

Predator 212 — predator212dyno.com

6.52 hp

Harbor Freight rate the engine at 6.5 and the model lands on it. The governor starts closing the throttle at about 3,600 rpm, so the peak arrives just under that — not because it has run out of breath, but because it is not allowed to continue.

Stock Predator 212

→ 8.37 hp

Nothing ported, swapped or jetted. Below 3,500 rpm the two curves are the same, because they are the same engine. Everything gained is above the point the governor used to intervene.

Pulling the governor

12.56 hp

A big cam, a race pipe, a rev coil and stainless valves, all breathing through the 18mm carburettor the engine left the factory with. The same build on a PWK24 makes 14.19.

What the stock carb costs

42 → 39

One engine, one build, two altitudes and nothing mechanical changed. At 5,000 ft it makes 9.40 hp instead of 10.26, and the main jet moves with the air.

Jetting for elevation

Gen 1 / Gen 2

Check the valve cover before you buy anything. Hemi covers are cast aluminium and rounded; Non-Hemi covers are stamped sheet metal, closer to a stop sign. Very little interchanges between them beyond the valves.

Hemi vs Non-Hemi

15.25 hp

The top of the naturally aspirated ladder on stock displacement. Be clear about what it is — a race engine, with no margin left for a mistake in assembly or jetting.

How to build a 15 hp 212

Our Story

Born in the Garage

Mike McGonigal learned to wrench from his dad. Not in a shop — in the driveway, on real cars, with real consequences. By the time he graduated high school he'd already built hot rods that ran. A '68 Mustang with a 351 Cleveland that ran elevens. An '83 Mustang GT with a 377 Windsor stroker that ran tens. Built by hand. Earned the hard way.

After school he went into sheet metal fabrication at Crane Carrier, learning how to run industrial equipment. Then the tower industry found him. Working for Rex Gotcher climbing communication towers, you don't just climb — you keep everything running. Diesel generators. Gas equipment. Trucks. Whatever it takes to stay on the air. Tower dogs don't call a mechanic. They are the mechanic.

When tower season slowed down, Mike went back to the shop. Dealerships. Independent work. Always wrenching. Eventually found a home as Chief Mechanic at Bottoms Up Chop Shop in Collinsville, Oklahoma. H-D Twin Cams, Shovelheads, Pan Heads, Knuckle Heads — he's turned wrenches on all of it.

These tools exist because after decades of building combinations the hard way, Mike decided to build something that helps every other builder skip the guesswork. The jetting numbers come from real carbs on real engines. The cam profiles are calibrated against published dyno data. The spring recommendations come from someone who's actually floated a valve into a piston.

McGonster Monster Motors LLC

Credibility

Lifelong wrench-turner

Hot Rods Built

'68 Cleveland · '83 Windsor

Best ET

10s in the '83 GT

Background

Tower dog · fabricator · chief mechanic

Current Shop

Bottoms Up Chop Shop, OK

Founded

June 2026 · Collinsville, OK

Admission Price

Free. Always.

How It Works

Build Your Combination

Every tool in the network works the same way. Pick your parts, see the result, buy with confidence.

Pick Your Engine

Choose your displacement, heads, cam, carb, exhaust, and every other variable that affects power. Each selector is stocked with real parts from real vendors.

See the Curve

The tool generates a predicted dyno curve — horsepower and torque vs RPM — based on real physics models calibrated against published dyno data.

Get the Jetting

Every carb in the network gives you a complete jetting recommendation — main jet, pilot jet, needle clip, fuel screw — adjusted for your elevation and temperature.

Buy with Confidence

Every part links to trusted vendors — Summit, JEGS, GoPowerSports, ARC Racing, and more. Compare prices, click through, and build it right the first time. Some of these are affiliate links — we may earn a small commission at no cost to you. It’s what keeps the tools free.

Shop Talk

Straight Answers, Honest Numbers

Engine building guides written by the same mechanic who calibrates the tools — anchored to published dyno data, not catalog promises.

Small Engines

How Much Horsepower Does a Stock Predator 212 Really Make?

Harbor Freight says 6.5 HP. Real dynos say it depends who calibrated the dyno. A working mechanic walks through what a stock, stage 1, and built Predator 212 actually make.

Read the guide

Harley-Davidson

The Twin Cam Upgrade Ladder: Stage 1 to 100+ HP, With Real Numbers

What a stock Harley Twin Cam 88, 96, and 103 really makes, what Stage 1 is honestly worth, and the cam and big-bore steps to 100+ rear-wheel HP — anchored to published dyno data.

Read the guide

Dodge V8

First Upgrades on a 5.9 Magnum: Where the Cheap Horsepower Hides

The Dodge 5.9 Magnum responds to one upgrade more than any other. Real dyno numbers for the cam swap, valve springs, and the honest upgrade path for a 360 Magnum.

Read the guide

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Contact

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