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Why is the Ford 302 block better than the 351W?

116K views 63 replies 22 participants last post by  machine shop tom 
#1 ·
OK, I know there are differing opinions here. Not being a "Ford gal" myself, I thought I'd pose this question to all you Ford fans out there.

I did some race engine shopping for a friend of mine this summer for his race truck. We wound up ordering our motor from Keith Craft Racing engines and are as pleased as pie. When talking with the engine builders about building this motor, all the builders that were really good and knowledgeable about Fords, wanted to work with the 302 block. While the builders who primarily work with Chevys, wanted to work from the 351W block. The hardcore Ford builders claim they can build a much better motor out of a 302 block (we wound up with a Ford Racing 302 block stroked to 331). Most of the high dollar stock car motors these guys build are based off the 302. Even Ford Racing themselves lists their 302 block as capable of 1200 HP, while the 351 block is only listed as capable of 750. Is this because of a different angle of the "V" that just works better or what?


Thanks in advance,

Barb
 
#2 ·
First of all the V must be 90 degrees or else the cylinders will not fire 90 degrees apart. This is why the crank throws are 90 apart also. My guess involves the main webbing. Being used to small block chevies, the first time I took a small Ford apart I couldn't believe the wimpy looking webs. While the Chevy is solid, the Ford is rather thin - a materials and weight savings for a stock engine I guess. As far as I know, the stock blocks differ only in deck height which would allow the 351 to have a thicker deck for better head gasket seal but I don't know if Ford did this. Can someone educate us? Good question!

The Vandal
 
#3 ·
Ford Motorsports blocks have nothing in common with factory engines installed in motor vehicles, the difference is probably in the way the Motrosports blocks are cast. Why one person likes one engine over another is anybody's guess, likely you are seeing personal preference more than anything else. Just like why some Chevy guys love 327 over 350's.

The 351W has a longer stroke and also a 1 inch higher deck height to fit a decent length rod into the engine, they are otherwise very similar engines except for the 49 cubes.

I doubt there is a real valid theoretical reson to prefer one or the other except for the extra 49 cubes, parts are cheaper for the 302 though.
 
#4 ·
The 351W has a heavier block casting wise, and looks like Ford intended to offer 4 bolt mains and never did ( the block has the metal for it). I don't believe the 302 is a better block from an engineering standpoint (probably the opposite) it does however have a lot more available parts. The big advantage is probably the smaller main and rod journals that slow down bearing speed and use up less HP. Overall a stock 351W is hands down stronger than a stock 302, thicker deck,cylinder walls,bigger head and main bolts, so it may be that the 302 is more easily built.
 
#5 ·
Originally posted by 4 Jaw Chuck:
<strong>Ford Motorsports blocks have nothing in common with factory engines installed in motor vehicles, the difference is probably in the way the Motrosports blocks are cast. </strong><hr></blockquote>

I'll agree with you here. Ford Motorsports may cast their 302 blocks to handle more ponies.

Stock for stock though, the 351W will handle more HP than a 302.

You can also get the 302 in an A4 block, which has a 4 bolt main.

[ September 18, 2002: Message edited by: BigBlockBabe ]</p>
 
#7 ·
Originally posted by BarbWire:
<strong> The hardcore Ford builders claim they can build a much better motor out of a 302 block (we wound up with a Ford Racing 302 block stroked to 331). Most of the high dollar stock car motors these guys build are based off the 302. </strong>
<hr></blockquote>

I wanna know who you talked to that you consider "hardcore". Everything I've read and been told says that the 302 is just weak. There's no way the stock car guys are using 302s.
 
#8 ·
i agree with woodz, there is just simply more metal in the 351 windsor block so logically, it should be stronger. but just like barb wire said, the 302 race block can handle 1200hp while the 351 race block only 750. i just looked in my ford racing catalog to confirm. Now that I think about it, it kinda makes sence. Its like having a pole thats 6 feet long versus a pole thats 12 feet long. If you held it strait out and have weight put on the end, the longer pole will obviously break or bend (depending on the metal) first. Maybe this is why the 302 block is stronger. Its more compact
An interesting thing to point out in the Ford Racing catalog is that they sell race 302 blocks in 2 different deck heights (8.2 and 8.7). The taller smaller one limited to 360ci and the taller one, 380ci and both rated for 1200hp. the stock production 302 block can only handle 347 and rated at 450hp and the stock 351(9.2" deck height) can handle 427 and and i dont know how much power. So here a question for you...Why even bother with the 351 race block when you can buy the taller "302" race block that can handle more power and keep up with displacement? THIS is probably why they recomended the 302 block.
 
#9 ·
Some of the Ford racing blocks use the 351C main sizes (between the 302 and 351W) for less bearing speed. I don't have my FRRP catalogue here to know whether it is th 302 or 351 block.Those Winston cup guys are also making that power with restrictor plates and little carbs ( I think 390 CFM ).
 
#10 ·
As I recall, several years ago there were some Ford engines built in Mexico that were preferred because they have more nickle in the cast iron. I think these were 302" blocks, but could be 351" as well, can't remember for sure. The Mexico blocks have "MEXICO" cast into the block somewhere, I think it is in the valley area. Anyway, these were the blocks that the "real" Ford guys were seeking. This was before Ford Motorsports came into being, so I am assuming that the SVO blocks are probably more desirable than the Mexico pieces.
 
#15 ·
Thanks for all the posts guys. And yeah, the Ford Racing catalog does offer a higher deck height 302.

As far as who I heard this from, I guess the best authorities I would post here would be Roush Racing (too expensive for our blood, but we did price them), and Keith Craft Racing Engines (which is where we bought ours from, these guys were great). There were other engine builders who stated the same (302 being a better build than the 351W), however, these are the only two I would consider to be big nationally known names.

It's pretty tough not believing them too, considering that the way the Ford Racing Blocks are rated...


Thanks guys!

Barb
 
#16 ·
There a few reasons why I think that the 302 block is listed as stronger. It may be hard to believe but a well casted 1969 351w can hold as much as 900HP when properly preped. I have seen a few. I personally have run these blocks well over 600hp. With a stock block being this strong you dont have a need for an after market block unless your wanting to get a larger bore size. The 302 block is different is alot weaker. The only option in stock blocks are the 302 boss which you wont find or the "Mexican block" which is really same the boss block but doesnt have 4 bolt mains. Mexican blocks do not have more nickel in them but they do have thicker webbing and mains. These blocks are getting pretty rare too. So the 302 has a real need for an after market block, so this may be a reason that they are as strong as they are because there is more of a market for it. Although the after market 351w block is only rated at 750 it doesnt mean it cant take more. Keep in mind some of these blocks are offered with larger bores and strokes to get more people to want them, so they are rated at its max bore size and max possible stroke. That block at STD or .030 may take 1100-1200hp.

Also one person mentioned that the 302 has a smaller bearing diameter, Just to note the 351w windsor bearing size is actually stronger in some aspects, the bearing size is really more RPM related then HP related.
 
#19 ·
Crankshafts for the 351W are several pounds heavier than the stroker 302/347 cranks... reciprocating weight is higher also...

Rotating and reciprocating weight costs horsepower.

Also remember the shorter the connecting rods, the more they flop around, and have more force trying to break them.
 
#20 ·
4 Jaw Chuck said:
Ford Motorsports blocks have nothing in common with factory engines installed in motor vehicles, the difference is probably in the way the Motrosports blocks are cast. Why one person likes one engine over another is anybody's guess, likely you are seeing personal preference more than anything else. Just like why some Chevy guys love 327 over 350's.

The 351W has a longer stroke and also a 1 inch higher deck height to fit a decent length rod into the engine, they are otherwise very similar engines except for the 49 cubes.

I doubt there is a real valid theoretical reson to prefer one or the other except for the extra 49 cubes, parts are cheaper for the 302 though.
The only valid point is that the 302 will fit into more unibody Fords than the 351W. That is, if you want a decent sized header.
 
#24 ·
302/351w

The 351W is built like Ford intended it to be a heavy duty 302 with 49 more cubic inches. All the bolts are bigger, all of the castings are beefer and the crank journals are bigger as well. It is in the same family as the 302/289 but not a lot of parts will interchange between them. In fact if my recollection is correct the only thing that interchanges without modification is the water pump, valves, starters, mechanical fuel pumps and the bell housing bolt pattern is the same. The crank shaft is larger in the journals, timing chain is longer, distributor shaft is longer, head bolts are a larger diameter and the camshaft has a different firing order, but if you change the firing order it will work.

These kind of things are what makes Ford confusing to some people. But think about this motor for a moment, it has excellent oiling, a strong block, a super camshaft thrust plate (no walking and no buttons required) and it shares crankshafts with the 351M. Aha, another confusing motor (save this one for another day). Well except for the rods and crank the 351m and the 400 are the same engine. So what does this mean? Well if the 351W shares the crank with the 351M and the 351M and the 400 are the same motor then lets bore the 351w 30 over, cut and relieve the block for crank counterweight clearance, drop the 400 crank in it, stick some Chevy valves in the early heads with screw in studs and guide plates and go spank some Heavy Chevy Donkey! It is a little bit more complicated then this but in 1982 I did this very thing. I had it in a Ford Futura with a C6 and a 9 inch. Street raced it often. Had a lot of fun with it and was never beaten!

Ford Motor Sports now offers a kit to do this and the last time I read about it you could take the the 351W block up to 454 CI. Can you imagine that? A 454 CI small block and it won't run hot on the street and you could drive it every day. With 454 CI you would be able to get an easy 500 hp out of it.

Now look here all of you die hard Chevy Fans, I cut my teeth on Chevys and I love them! But Ford is cool too. You just have to use your brain a little more.
 
#26 ·
One man's opinion is another mans rectum. Go to Ford Motor-sports and read about the 454 Windsor block. I did not say you could take the 351w to 454 I said Ford Motor-sports now offers a kit. Check your journal dia between the 351W and the 351M, believe me it fits. Do some study on the early 351w four barrel heads these are the ones that Edelbrock modeled theirs after.
 
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