347 Stroker vs 351 Windsor: Which Should You Build?

A 347 stroker and a stock 351 Windsor end up within a few cubic inches of each other, but they start from different blocks. The 347 is a 302-family block (8.2 in deck) with a 3.400 in stroke and 4.030 in bore; the 351W is a taller 9.5 in deck block with a 3.500 in stroke and 4.000 in bore, and a stock 351W block can be stroked to 408; the 427 kit we list needs an aftermarket 351-family block. Choose by the space in your chassis and how far you want to go later.

Key takeaways

  • 347: 302-family block, 4.030 in bore x 3.400 in stroke, 347.0 ci, 5.400 in rods in the kits we list.
  • Stock 351W: 4.000 in bore x 3.500 in stroke, 351.9 ci, 9.5 in deck height.
  • The 302-family block is shorter (8.2 in deck), so a 347 keeps the 302's block size.
  • We list a 408 kit for a stock 351W block (Scat 1-94306, plus Eagle 14129030) and a 427 kit (Scat 1-46580BI) for aftermarket 9.500 in deck blocks with 2.750 in Cleveland-size mains.
  • Measure your chassis and send us your goal before you pick.

347 vs 351W compared

Displacement = bore x bore x 0.7854 x stroke x 8, rounded. Specs are from each manufacturer listing on our store. Stock 289/302 and 351W figures are Ford factory specs. Deck heights are nominal.
347 stroker Stock 351 Windsor 351W stroked (kits we list)
Block family 289/302 351 Windsor 351 Windsor (408); aftermarket 9.5 in deck, 2.750 in mains (427)
Deck height 8.2 in 9.5 in 9.5 in
Bore 4.030 in 4.000 in 4.030 in (408) / 4.125 in (427)
Stroke 3.400 in 3.500 in 4.000 in
Displacement 347.0 ci 351.9 ci 408.2 ci / 427.7 ci
Rod length (kits we list) 5.400 in - 6.200 in (Scat 1-94306 408), 6.250 in (Eagle 14129030 408), 6.250 in (Scat 1-46580BI 427)
Kits we list Eagle 14003030, Eagle 16003030, Scat 1-94160, Scat 1-94165 - Scat 1-94306, Eagle 14129030, Scat 1-46580BI

Still deciding? Tell us your combo or call 310-784-1010.

Which should you build?

  1. Measure your engine bay: the 351W block is taller than the 302 family, so headers, oil pan and hood clearance can change.
  2. Decide whether you want room to grow: a stock 351W block takes the 408 kit we list; the 427 kit needs an aftermarket block with 2.750 in mains and a 4.125 in bore.
  3. Check the block you have, or plan to buy, with your machine shop.
  4. Pick the kit from the listings: crank and piston material, rods and balance.
  5. Send us your vehicle and goal, and we'll help you choose.

Frequently asked questions

Is a 347 or a 351W better?

Neither is better for every build. A 347 puts about 347 ci in the shorter 302-family block (8.2 in deck height); a stock 351 Windsor has about 351 ci in a taller 9.5 in deck block that takes a 408 stroker kit; 427s need an aftermarket block. Tell us your car and goal and we'll help you choose.

Will a 347 fit where a 302 fits?

The 347 is built in a 302-family block, so the block itself has the same deck height and outside size as the 302. Oil pan, headers and accessories still need checking for your chassis, so measure and send us your vehicle.

Can a 351W be stroked further?

Yes. A stock 351W block can be stroked to 408 (4.030 in bore, 4.000 in stroke): we list Scat 1-94306 (6.200 in rods) and Eagle 14129030 (6.250 in rods). The Scat 1-46580BI 427 needs an aftermarket 351-family block with a 9.500 in deck, 4.125 in bore and 2.750 in (Cleveland-size) main journals, such as a Ford Performance BOSS 351 9.5 in deck block; it won't fit a stock 351W block (3.000 in mains). Ask us about your block first. Scat 1-46580BI comes internally balanced.

Ask a Coast High Ford builder

Ford strokers are what we build. Send your engine, goal and transmission, and a Coast High builder will get back to you. Or call 310-784-1010.

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Written by the Coast High Performance tech team. Checked by CHPTech Nov 4, 2026. Last updated November 4, 2026. Specs come from each manufacturer listing on our store. Questions? Call 310-784-1010.

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