351W vs 302 HO

Discussion in '1994 - 1995 Specific Tech' started by mo_dingo, Nov 22, 2003.

  1. I've been searching google for an article that shows the differences between the production 351W and the 302 HO......but to no avail.

    I am under the impression that the 302 HO has the same block as a 289. Also, I've been told that the 351W is a 302, just bored .060 over, and has a "stroker" crank.

    For production 351W, are the heads E7's, or something else? I know the intake manifold won't say 5.0 HO, but is the stamping the only difference on the intake manifold? I've also heard the head bolts have a different diameter (7/16 - 5.0, 1/2 - 351W).

    How far can a 302 be bored/stroked without risking too thin of cylinder walls? I have heard of people going to a 408 from a 351W, but I may be mistaken.

    If anyone can post a link to an article answering my questions, it would be a great help. I need to show a friend the article because he has a 351W bronco (1990) and wants to know any and all differences between the 302 HO and the 351W.

    Peoples opinions are appreciated, but an article is what I am ultimately looking for.
  2. I thought the block is taller so the stroke can be greater and the bore is the same on a 351W?
  3. a 302 can go to 347 safely, and a 351 can go to 408 safely....and as said before the deck hight of the 351 is taller and thats why it can run a lager stroke
  4. Who ever said this is a complete idiot. a 302 can only be stroked to a 347, that is wit a .060 bore. 351 is a completely different engine. the 302 is not a 289, the block is longer take a look at a 96-98 mustang you will see about 5-6 inches between the fan and the engine a 94-95 only has about 3-4.

    I don't know about the heads, but the intake is wider than a 302 being that the engine is wider. The Head bolts are different but you can put a 302 head on a 351 being that the mounting points are the same.

    The 302 can be safely stroked to a 347 and bored 60 over without causing a thin cyl wall situation, but it also depends on the motor

    http://www.fordclassics.com/enginespecs.html this is very basic
    You might want to go to a library and check out a bronco shop manual, they should have the diameters of evey nook and cranny in them of both blocks.

    All I can tell you is that they are two different blocks, the 351 has thicker walls, and can be bored out to 400+ ci and that it too is a small block. They made two different 351 engines a cleveland and a windsor, but the windsor is the one that will fit into a mustang engine compartment.
  5. A 302 is an enhanced version of a 289, Ford extended the cylinder bores for better stability. A 351W has the same 4.00" bore that a 302 has, but a 3.50" stroke (as opposed to the 3.00" stroke on a 302). There are different versions of the 351W available with different deck heights, late model production blocks are 9.5". The 302 has a 8.2" deck height. Heads for 302 and 351 are interchangeable, but the head bolt size is different, as you mentioned.

    347 is typical for the 302, 408 is typical for a production 302. There are some aluminum 351W versions that can be stroked to 454. DART 351's can go to 468.

  6. 96 and new use a SOHC 281 which is completly different but he was talking about the 289 block form older mustangs and it is the same basic block.

    also i didn't relized that the dart block could be taken so far...i am only aware for the specs for factory block i haven't delt much with after market blocks
  7. Yeah. I believe the Dart 302 block can also be stroked to about 385 cubes (maximum recommended on their site). They offer them in 8.2 and 8.7" deck hieghts.

    I'm looking at the Dart blocks myself. They're fairly strong too. Too bad they cost so damn much.
  8. I beleive that a 347 is .030 over with 3.40 stroke and 5.400 length

    And FMS makes or did make the R-block which is 8.2 deck height and is a 4 bolt main and the S302 which is a four bolt main with a 8.7 deck height which would allow for a larger stroke just like dart.
  9. 351w has a different intake, firing order is different than a non-HO 5.0 but the same as a 5.0 HO. You'll need a new flywheel too I think.

    351W block is just as strong as any aftermarket 302 block save for the Dart blocks...
  10. Actually 289 & 302 is basically the same block. The cylinder lengths have been measured and were found to be the same. In other words, 302 is a stroked 289, with 1/8" longer stroke - not much difference there.
  11. ps sorry to bring up an old thread...didn't see that :(
  12. 351W and 302 differences

    The 351W is identical to the 302 from about 8.5" up the deck downward. Both are 4" bores but the 351W has a longer stroke and longer deck (longer piston bores). Both are SBFs and will bolt up to the same bell housings, motor mounts, etc. Even the timing chain cover, etc is identical. There are custom 351W engines (www.dartheads.com) with extended deck heights allowing strokers to 468 or so cubic inches. Dart makes a 351W in aluminum or iron with 4 bolt mains and Cleveland crankshaft bore diameters (smaller for more velocity).

    There are stroker kits for 302 engines and a common one is 347 cid. This doesn't mean that that engine can be safely stroked to 347 though... it depends on your application. To get 347 out of a 302 there is some grinding away of clearance points on the bottom of the cylinder walls and elsewhere to allow the crank clearance to turn. Also very short skirted pistons are used... this causes more oil blow by and slop and so more piston wear. This is especially true on turbocharged or supercharged engines. My recommendation would be to stroke to 331 cid for blown engines (or NOS engines). Same with the 351W engine... just cause it can go to 468 it doesn't mean this is safe for your application.

    Another thing... someone called someone else an idiot for thinking the 302 SBF was the same engine as the 289 SBF. I can tell you the indeniable truth is that these are identical blocks in everyway you can measure. You can take a 289 block and drop a 302 crank into it and you have a 302. You can take a 302 block and drop a 289 crank into it and you have a 289. The bore is the same... so is EVERTHING esle. The stroke is different.

    I have a 289 block with a 302 crank overbored 0.060 in my Stang right now. It is bored out some so I get about 307 cid out of it.
  13. Not true... the 302 cylinder bores are identical to the 289. In fact... I challenge you to tell me where there is any difference in measures in either engine block. There is none.
  14. 351W are often stroked to 408. You can push any of these engines further by compromising the strenght of other components like pistons, cylinder walls, etc. You could go to a maximum displacement on an engine that was to operate at lower rpms, no NOS, no supercharging, compression of 10:1 or less (swag)... the key is that you would have to make some compromises to ensure a lasting engine.
  15. Hey JayD, how are you quoting HairyCanary in your posts when Rootus was the one that said that?
  16. Cause Rootus is Hairy Canarys new name.
  17. I see. Deception is the key to understanding :D Was he the MysteryStanger? :rolleyes:
  18. The mains in a 351w are also bigger (diameter) than the 302. So, the crankshafts are not interchangeable.
  19. The bores are the same, the skirts on the 302 were made longer for piston stability. That is the only difference that I know of for sure, I believe the rest is identical.