351W Block question.

most any 351 block will do fine except as noted the 69/70 blocks have a shorter deck height so pistons may be a problem, i'd advise contacting the piston manufacturer to see which block the particular pistons are designed for. for instance the long rod 351w i plan on building the KB pistons i'm going to use are designed for the 71-later blocks and they said that the pistons would stick out of the block if i used a 69/70 block. also the late 70's and early 80's 351 blocks aren't as strong as the earlier or later blocks i believe because they used a higher "gray" iron content.

bnickel said:

most any 351 block will do fine except as noted the 69/70 blocks have a shorter deck height so pistons may be a problem, i'd advise contacting the piston manufacturer to see which block the particular pistons are designed for. for instance the long rod 351w i plan on building the KB pistons i'm going to use are designed for the 71-later blocks and they said that the pistons would stick out of the block if i used a 69/70 block. also the late 70's and early 80's 351 blocks aren't as strong as the earlier or later blocks i believe because they used a higher "gray" iron content.

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Irregardless of the metal used, the early (69-74 or so) 351w blocks have much, much thicker main bearing web supports. This is a known fact and it was very apparent when I compared my old 71' block to my 89' block. There was no question structurally as to which is stronger when both are compared.

If one were so inclined, it is possible to drill 4 bolt main caps on the early blocks, the later block has no real meat for it.

In the end, unless you are putting out much over a true 500-550hp, ANY year 351w block will work. You can go higher than that, but you must pay more attention to your tuning. If you want more than 550hp, save your pennies for a Dart block. Also save up for the suspension and drivetrain that such a monster will require.

Trust me when I say that a 500hp street engine is more than a handful for most people and definitely leads to severe cases of the pucker factor. . . .

I have a collection of about a dozen C9 and D1 351W blocks. Without re-hashing what's already been said, these blocks have noticeably beefier main webs than the later D2 and D4 blocks. The next 351W block that had beefy mains was the E3 H.O. truck block used for 3 years. It overlapped production with the E4 truck block, which eventually replaced the E3 as the H.O. block. While it's very likely that D1 production overlapped D2 production, as Ford seems to do some really crazy things with their engine lines, I have only actually seen 69 -71 Fords with either C9 or D1 351W blocks. One big benefit of the C9 or D1 block is that they were cast with bosses to accept 4 bolt mains. Of course no production block ever came with them, but they are easily added. I put splayed caps on mine, although they were designed for vertical bolts. There is enough meat to use a splayed cap, and they pull on the sides of the block to strengthen the bottom end. Quality of machining and assembly will play a key role in how well your engine holds up. A local drag racer who runs mid 9s in a 70 fastback with a 408 stroker hasn't had a problem in two seasons of racing. A local dirt tracker cracked a C9 block last season, and he was only making around 550 hp tops with a stock stroke.

my last 2 351w's were both D0OE blocks. they are out there. i currently have a D1OE block and am looking for an F4TE block.

Hmmm... I have noticed a lot of people are saying 500 is the limit of a 351w?

I have sen many many over 500 hp Windsor motors. Infact one of them is mine. I was pushing 600 plus at the rear wheels and have had no problems what so ever. In fact I know someone that had a stock rotateing assemnly but with forged pistons push over 800 but he ended up bending his connecting rods. It seems that the connecting rods are the weak link to the 351s. I think if your goal is 500 you are more than safe with a 351w just make sure you have a good machinist and a good balance with quality fastners and hardware and you should be fine. RPMs it what seems to kill the blocks so build something that makes power to about 6,000.

And about the 302s. The late model years are "thin cast" walls. They are usually only good up to 400-500 wheel hp. If you can find an earlier "Mexican" block they have thicker main caps and that is were a lot of the blocks tend to crack. I have cracked a late model block with and with my estimates was around 400 hp.

Like mentioned above even a TRUE 400 wheel HP car is a handful on the street. I have ridden in many wannabe 400 hp cars and then I let them ride in my acutal 400hp car they can't believe the difference.

Thats just my .02 cents.

Also a good company I have used in the past is Ford Perfomance Solutions. They are very helpful and decent prices. That is were I bought my last short block from and he worked with me cause I wanted a low compression motor with I-beam rods to make close to 800-900 hp. I haven't gone that far up and I don't think I will since I like to keep my engine going! Also we made it so I redline at 7200 with the long rod 357w But I am keeping my revs down to 6000

Just as a side note, I believe the urban Ford legend of the high nickel content may have come about in late 1982 or early 83, when Ford got back into racing and cast a run of 351 Cleveland blocks in Australia for use in Winston Cup racing. This was the fastest way to get back into racing as they didn't release the 351W SVO block until March 1984. I haven't found any literature to back it up, but I recall some advertisement back then or perhaps a magazine article that referred to the new (for 1983) Aussie Cleveland racing blocks as having a high nickel content. These were never meant for production cars, so the extra wear on machining tools would be tolerable.

And for BNickel, I didn't say there is no such thing as a D0OE 351W block, just that I've never run across one in over 15 years of collecting early 351W blocks. I've seen D0OE 351W heads on C9OE blocks, but no D0OE blocks.

69gmachine said:

And for BNickel, I didn't say there is no such thing as a D0OE 351W block, just that I've never run across one in over 15 years of collecting early 351W blocks. I've seen D0OE 351W heads on C9OE blocks, but no D0OE blocks.

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i was just saying they are out there.

My uncle also has a 69 351W! I'm thinking he should save it for parts for my 70 Mach 1

i split my '69 351w block in no time.

paul302 said:

i split my '69 351w block in no time.

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I hope I have better luck. Was it the block that failed? Or a casuality of another part failing?

From what I've heard, stock 351W blocks are good to around 650HP.

BottleFed70 said:

I hope I have better luck. Was it the block that failed? Or a casuality of another part failing?

From what I've heard, stock 351W blocks are good to around 650HP.

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the block cracked (#2 main to the cam journal). everything else was fine, luckily.
i'm making more than 650hp, so i'm not blaming the block.

Use the one you have on hand and/or can afford. There are too many choices to list and argue over. C-4, C-6, FMX, AOD, E4OD, T5, Toploader 4 speed, yada, yada, yada.