347 Stroker Engine: Specs, Horsepower and Ford 347 Crate Engines
A 347 stroker is a small block Ford built on a 302-size block with a 3.400″ stroke crankshaft and, usually, a 4.030″ bore, which raises displacement from 302 to about 347 cubic inches. It keeps the 302’s external size, deck height and mounting points, so it fits where a 302 fits, but it adds torque across the rev range. The 347 crate engines we list are rated at 415 HP.
347 stroker specs
| Specification | Typical 347 stroker |
|---|---|
| Base block | Small block Ford 302 (5.0L) size, 8.206″ deck |
| Bore | 4.030″ (0.030″ over the 302’s 4.000″) |
| Stroke | 3.400″ (the stock 302 is 3.000″) |
| Displacement | About 347 cubic inches (5.7L) |
| Connecting rods | Most kits use 5.400″ rods, against 5.090″ in a stock 302 |
| Firing order | Same as the 302 it is based on; see our Ford firing order guide |
The displacement comes from the standard formula: bore x bore x stroke x 0.7854 x 8. With a 4.030″ bore and 3.400″ stroke that works out to about 346.9 cubic inches. Because the deck height does not change, the longer stroke is packaged with a shorter piston compression height, and in many 347 builds the piston pin sits close to or through the oil ring groove, which is why piston and ring choice matters in a 347.
How much horsepower does a 347 stroker make?
It depends on the heads, camshaft, compression and induction far more than on the 347 cubic inches. The new 347 crate engines we list are all rated at 415 HP, and the BluePrint 347 EFI engine’s specification table also lists 415 lb-ft of torque with 10:1 compression, aluminum heads and a hydraulic roller camshaft. Home-built 347s vary widely with the parts chosen.
347 vs 302, 331, 351W and 408
| Engine | Block | Bore x stroke | Displacement |
|---|---|---|---|
| 302 | 302 (8.206″ deck) | 4.000″ x 3.000″ | about 302 ci |
| 331 stroker | 302 | 4.030″ x 3.250″ | about 331 ci |
| 347 stroker | 302 | 4.030″ x 3.400″ | about 347 ci |
| 351 Windsor | 351W (9.480″ deck) | 4.000″ x 3.500″ | about 351 ci |
| 408 stroker | 351W | 4.030″ x 4.000″ | about 408 ci |
- 347 vs 302: the 347 adds about 45 cubic inches and noticeably more torque in the same external package. Our Ford 302 engine guide covers the 302 itself.
- 347 vs 331: the 331 uses a shorter 3.250″ stroke, which leaves more room for the piston and rod, so it is sometimes chosen for very high RPM. The 347 gives more displacement from the same block.
- 347 vs 351W and 408: the Windsor has a taller deck, so it can take a longer 4.000″ stroke and become a 408. It is a bigger, heavier engine; the 347 suits cars where a 302 is the comfortable fit. We list the BluePrint Windsor 408 (450 HP, 470 lb-ft), built on a two-bolt main block with a 4.000″ stroke crankshaft.
More on stroking in general: what is a stroker engine.
347 stroker kit or 347 crate engine?
A 347 stroker kit (rotating assembly) gives you the crankshaft, rods and pistons to build your own engine in a 302 block, which then needs machining, balancing and careful clearance checks. A 347 crate engine arrives assembled. We do not list a 347 stroker kit; our rotating assemblies include an Eagle 351W kit that builds a 427, and other stroker kits for Chevy and Ford engines.
347 crate engines we list
| Engine | Version | Rating | Price |
|---|---|---|---|
| BluePrint SBF 347 (BP3479CT) | Base engine | 415 HP | $7,199.00 |
| BluePrint SBF 347 (BP3479RCT) | Base engine | 415 HP | $7,199.00 |
| BluePrint SBF 347 (BP3479RCTC) | Base dressed | 415 HP | $7,949.00 |
| BluePrint SBF 347 EFI (BP3479CTF) | Base dressed with EFI | 415 HP, 415 lb-ft | $8,999.00 |
| Ford Performance 347 spec engine (M-6007-D347SR7) | Base engine | 415 HP | $15,019.99 |
The BluePrint 347 EFI engine uses a four-bolt main cast-iron block, a forged 3.400″ stroke crankshaft, forged 10:1 pistons, aluminum heads and a front sump oil pan. Prices change; check the product page for the current price and the exact included parts. Every order ships for a flat $75 to any US state. See all small block Ford crate engines and compare dressing levels in long block vs short block.
Before you buy a 347
- Balance: small block Fords are externally balanced, and the balancer and flywheel or flexplate must match the engine’s imbalance. Early 289/302 engines used 28 oz, later 5.0L engines 50 oz. The BluePrint 347 EFI lists 28 oz external balance front and rear.
- Oil pan and sump: front-sump and rear-sump pans fit different chassis. The BluePrint 347 EFI uses a front sump.
- Water pump rotation: the BluePrint 347 EFI notes that its timing cover suits a standard-rotation water pump and pulley kit only.
- Carburetor or EFI: EFI engines need a suitable fuel pump and lines. Compare the two in carburetor vs fuel injection.
Frequently asked questions
What is a 347 stroker?
A small block Ford 302 block fitted with a 3.400″ stroke crankshaft and pistons for a 4.030″ bore, which makes about 347 cubic inches.
How much horsepower does a 347 stroker have?
The 347 crate engines we list are rated at 415 HP. Built 347s vary widely with the heads, camshaft and induction.
What block is a 347 stroker based on?
The Ford 302 (5.0L) small block, so it keeps the 302’s 8.206″ deck height and external dimensions.
Is a 347 better than a 302?
It makes more torque and usually more power in the same size package. A 302 costs less to build and has more room for piston and ring design.
Will a 347 fit where a 302 fits?
Generally yes, because it uses a 302-size block. Check the oil pan sump position, balance and accessory drive against your vehicle.
Related: Ford 302 engine, stroker engines, Ford firing order, 2-bolt vs 4-bolt mains, 347 crate engines, all guides.
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