Trick Flow PowerPort 195 vs 225 on a street 351C
Engine dyno, as configured — flywheel horsepower. Standard test config: stock manifolds through 18" of pipe, air cleaner lid flipped, no accessories driven. Factory SAE net ratings are measured as‑installed and read 15–25% lower. Rev ceiling for this combination: 6000 rpm.
Where each one wins
| RPM | PowerPort 195 | PowerPort 225 | diff |
|---|---|---|---|
| 2000 | 308 | 319 | +11 |
| 2500 | 333 | 345 | +12 |
| 3000 | 361 | 375 | +13 |
| 3500 | 398 | 413 | +15 |
| 4000 | 433 | 445 | +12 |
| 4500 | 450 | 460 | +9 |
| 5000 | 443 | 453 | +10 |
| 5500 | 429 | 441 | +12 |
| 6000 | 407 | 422 | +15 |
Torque, lb-ft, at the flywheel. Everything except the part named is identical between the two runs.
Trick Flow sized the 195 deliberately close to the factory 2V port, and the 225 is the big one. Same casting family, same valve angles, different runner volume.
On a 351 with a street cam the 195 is usually the right answer and the 225 is buying top end you will not use. Put a stroker under them or a much bigger cam and that flips.
The rule is not "bigger head, more power." It is "match the port to where the engine spends its life," and this pair is the cleanest way to see it.
The build
| Block | Factory 351C 4-bolt main (Boss/HO) |
|---|---|
| Crank | Eagle forged 4340 — 3.50" stroke / 351 ci (~$700) |
| Rods | Aftermarket I-beam forged (Eagle/Scat) — to ~600 HP |
| Pistons | Generic flat top (0cc) |
| Head gasket | OEM compressed (.040") — neutral |
| Cylinder heads | Trick Flow PowerPort Cleveland 195 (62cc CNC) |
| Porting | As-cast / stock |
| Camshaft | COMP XE274H — hyd flat (32-246-4 · 230/236 @.050 · .562"/.565") — Holdener +44 HP vs Boss cam |
| Valve springs | COMP 916-16 dual |
| Rocker arms | Stock stamped 1.73 rockers |
| Intake manifold | Edelbrock RPM Air-Gap |
| Carburetor | Holley 750 cfm — street/strip sweet spot |
| Exhaust | Long tube 1-3/4" — hot street |
| Ignition | MSD Pro Billet distributor + 6AL box — ~8,000 rpm |
| Fuel | Pump 93 octane |
| Air cleaner | Stock air cleaner, LID FLIPPED — DYNO STANDARD |
The other one
| Block | Factory 351C 4-bolt main (Boss/HO) |
|---|---|
| Crank | Eagle forged 4340 — 3.50" stroke / 351 ci (~$700) |
| Rods | Aftermarket I-beam forged (Eagle/Scat) — to ~600 HP |
| Pistons | Generic flat top (0cc) |
| Head gasket | OEM compressed (.040") — neutral |
| Cylinder heads | Trick Flow PowerPort Cleveland 225 — 339/244 cfm (published chart) |
| Porting | As-cast / stock |
| Camshaft | COMP XE274H — hyd flat (32-246-4 · 230/236 @.050 · .562"/.565") — Holdener +44 HP vs Boss cam |
| Valve springs | COMP 916-16 dual |
| Rocker arms | Stock stamped 1.73 rockers |
| Intake manifold | Edelbrock RPM Air-Gap |
| Carburetor | Holley 750 cfm — street/strip sweet spot |
| Exhaust | Long tube 1-3/4" — hot street |
| Ignition | MSD Pro Billet distributor + 6AL box — ~8,000 rpm |
| Fuel | Pump 93 octane |
| Air cleaner | Stock air cleaner, LID FLIPPED — DYNO STANDARD |