How to make 300 hp from a 351 Cleveland 2V on a budget
within 1% of peak across that whole range
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: 5900 rpm.
Three hundred from a 2V is the cheapest real horsepower on this site, and the reason is in the factory numbers. A 1970 351C 2V was rated 250 gross with a 2-barrel, cast-iron manifolds, and a cam so mild it was designed around emissions. You are not building an engine; you are removing three restrictions — the 2-barrel, the manifolds, and the cam — and leaving everything expensive alone.
The order matters because the parts interact. The 4-barrel intake on its own does almost nothing on the stock cam, because the cam cannot use the airflow. The cam on its own overheats the stock springs and floats by 4,800. Do all three together — intake, 600 cfm carb, XE256H with its springs, 1-5/8" long tubes — and the number up top is a conservative figure for the combination, not an optimistic one.
What to leave alone: the heads (the 2V port flows plenty at this level), the bottom end (factory I-beams and cast crank are fine to 450), and compression (9.7:1 on flat tops runs on pump 87 without drama).
Three hundred honest horsepower out of a 2V is a cheap build, because you are not touching the heads. A mild hydraulic cam, a four-barrel intake that fits 2V ports, a 600 and a set of long tubes.
The 2V head is not the limitation people say it is at this power level. It flows plenty for three hundred, and it keeps the port velocity that makes a street car feel strong off idle.
Springs are the one place not to save money. Whatever cam you pick, buy the springs that match its lift or the cam cannot do its job.
The build
| Block | Factory 351C 2-bolt main (stock) |
|---|---|
| Crank | Stock cast iron — 3.50" stroke (351 ci) |
| Rods | Stock I-beam (factory) — builders' guide ~450 HP |
| Pistons | Generic flat top (0cc) |
| Head gasket | OEM compressed (.040") — neutral |
| Cylinder heads | 2V US open chamber (75cc) — the common head |
| Porting | As-cast / stock |
| Camshaft | COMP XE256H — hyd flat (32-241-4 · 212/218 @.050 · .487"/.493") |
| Valve springs | COMP 987-16 dual |
| Rocker arms | Stock stamped 1.73 rockers |
| Intake manifold | Edelbrock Performer 351-2V #2750 — 4bbl flange, 2V ports |
| Carburetor | Holley 600 cfm 4150 |
| Exhaust | Long tube 1-5/8" — street |
| Ignition | Pertronix Ignitor II — hotter spark · ~7,000 rpm |
| Fuel | Pump 93 octane |
| Air cleaner | Stock air cleaner, LID FLIPPED — DYNO STANDARD |
The 12 hp between a driveway tune and a dyno tune on this combo is mostly timing. A 2V with 9.7:1 and a 256 cam will take more total timing than the factory setting on pump 87. Set it on a dyno or set it with a timing light and a plug read, but set it. Calibration note: no published dyno pull exists for exactly this combo; this page is anchored to the factory 2V rating at one end and to the 4V tests at the other. If you dyno one, send the sheet.
Change these numbers yourself