FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Machspeed on March 09, 2017, 11:27:35 AM
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These have been out for some time and are sold by a few different companies but they are not available for an FE.
http://www.horsepowersales.net/
I'm in the middle of a 11.5:1 compression, internally balanced, 428 build that will be using a 105 block and will be seeing nitrous. I'm concerned about how long it will last. How much power does it take to kill a non cross bolt block? I know there's a lot of variables that contribute to failure but I'm just wondering how far I can go.
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Nope. I've seen lots of weak-assed OEM 5.0 (302 Windsor) blocks split down the middle after taking lots of heavy 250hp+ nitrous shots and lots of racing time.
https://www.google.com/search?q=split+5.0+blocks&rlz=1C1SAVS_enUS541US568&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj8mNif7cnSAhWJ8oMKHdPXCRMQ_AUIBygC&biw=1024&bih=490
But unless someone else here differs, I've never seen even one web shot of any FE block doing the same. Cam tunnel cracks yes, often diagnosed as a odd loss of oil pressure. Methinks Ford had it right when NASCAR testing and actual track breakage lead to cross-bolted mains.
Somebody else here will need to pipe up on how many horses...but even Ford's own literature on (Windsor based, not the newer FR9 engine) NASCAR grade block topped out at 750 hp. Perhaps not the best comparo but....................
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I think the old fashioned name for valley girdle is intake manifold.
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There is certainly a reason why the aftermarket FE blocks all have three ribs running across the valley, I'm sure it helps stiffen up the block somewhat. But I agree that the main issue with FE blocks is the two bolt caps on the non-crossbolted versions; I don't think it would make sense to reinforce the lifter valley without shoring up the mains first...
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There was a guy making an internal lifter gallery girdle for the 5.0L blocks some years ago but he got a lot of heat for selling snake oil and the 5.0L community drummed him out of town. Whether it worked or not who knows. But there is kind a lack of a good way to bolt it inside the block without drilling holes and making the block even weaker.
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Agree with babybolt. There's no good way to fasten such an animal to the block and get any meaningful structure benefit.
Want structure across the valley? Bolt on a 2V cast iron intake. I guarantee that is stiffer than any valley plate you could buy :D
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I know the horsepower limit of stock blocks has been questioned many times but how much insurance does crossbolting the block give you? I've read that pushing a stock block past 600hp will make it fail but I don't think anyone says if this limitation is for a 2 bolt block or a crossbolted one. My motor should make a little more than 500hp n/a and then I'm planning to hit it with another 125-250hp shot of nitrous. I'm planning to buy an aftermarket block later on so I'm wondering if I should spend the money to cross bolt this block or not. I have no interest in filling the block as I plan to drive the car on street from time to time and the filler may cause it to run a little warm. Jay, given your experience, am I asking too much from a factory block? Would crossbolting the block allow it to handle 700-800hp?
Sorry if I should have started a new thread for this...
Thanks for all the replies. I almost made a post that simply said "What killed your FE?"
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General rules of thumb, and my opinions only, on stock FE blocks:
- Stock run of the mill FE block: Good for up to 600 HP
- 428 block with additional webbing around the 2 bolt mains: Good for up to 675 HP
- 427 crossbolted block (or any FE block that has been crossbolted): Good for up to 800 HP
The above statements assume that the bores are in reasonable shape, and not overly thin. The main failures I've seen with FE blocks is cracks along the oil passage running from the main saddle to the cam saddle, on mains 2 and 4. Crossbolting makes a big improvement in these areas.
Also in my opinion, aftermarket blocks are good for well over 1000 HP, and probably more like 2000 HP.
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This is just my opinion. There have been several members of the FE forums over the years who have run nitrous, and every one of them eventually split the block below the cam tunnel. These weren't big HP engines either. I think Jay is pretty good with his numbers, assuming good quality machine work, but I'd feel a little uneasy running the old iron that high. Especially with nitrous, which is a whole different animal. The shock loads are really bad with nitrous, and the weak point on the FE is the webbing below the cam, right where all the stress is. It doesn't make sense to me to push a stock block to the limits with nitrous. It will fail. If I wanted to push 650-750 hp on nitrous, I'd seriously be looking at an aftermarket block.
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One more thing: detonation.
Regardless of the block, unintended detonation (bad fuel, timing, No2 fuel solenoids failing, poor tuning, oiled cylinders and more) will at high rpms kill just about any block. Even low amounts of detonation can cause cap walk, capfretting and more. So often those broken 5.0 blocks and maybe some cam tunnel stuff in FE's may or can be traced to this issue and not only pure block strength.
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All valid points. And let me add one more thing, track use. If you are dumping the clutch at 5000 RPM with slicks on the back of the car, or leaving on the trans brake, you will eventually wreck any non-crossbolted block.
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I agree. All valid points. I'm running a manual transmission with slicks in a sub 3000 lbs car. I'm planning to keep the launches on the conservative side, maybe 3-3500 RPM. I have experience with nitrous so I have an idea of what I'm getting into but as mentioned things happen. I called this morning about buying a Pond block and I was told that they have been on order since June. I'm looking at just crossbolting this block and running it until I can get an aftermarket block. Does anybody have any experience with the BBM blocks?
Again, thanks for the advice.
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Agree with planned usage being a huge contributor to block life. I have had a few 428 blocks split main webbing and cylinder walls, with well under 600 HP. However, these engines spent most of their "working lives" running very low 10 second 1/4 mile runs, with a 4 speed. Although I did not rev them really high (6000-6200 RPM clutch dump, 6200 RPM shift points, 66-6800 across the finish line), it still took its toll(s).In a mostly street cruiser, with an occasional full throttle blast lasting a few seconds or so, these blocks likely would have lasted for decades.
As for nitrous, I did play with it for a few years, in the late 80s. At that time I had a 390 and a C6 in my Fairmont, it was running 11.40s @ 117 MPH. I added a NOS "Cheater" system, with adjustable jets. With 125 HP jetting, it ran 10.4-5s, and almost 130 MPH, with no real issues, but a little later, I got greedy (easy to do with power adders), and switched to 175 HP jets. The ETs improved to high 10.2s, at 132 MPH, but after a few months, I had the pleasure (?) of sliding across the finish line at over 130 MPH, sideways, while sliding along in the oil and coolant that got under the rear slicks, when the 390 disintegrated. The 105 block had torn all 5 main webs out between the cam and crank bores, and broke the crank into 5 pieces. One cap split down the middle, the rest split right thru the main bearing bolt holes in the block. The oil pan rail was bulged out almost an inch, the flexplate teeth sawed thru the bellhousing, broke off the starter, and the C6s stator support/input shaft, etc, quite a mess. Sold off all my blue bottle stuff, and stay naturally aspirated ever since.
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Agree with all of the above.
Nitrous is the hardest power-adder (by far!) on the bottom end of an engine. When you hit 50-year old parts with the stuff, you get unpredictable results. The added oxygen spikes the cylinder pressures much more quickly than normal combustion - almost the way detonation does. The poor bottom end components have to absorb these huge sudden loads early, before the crank pin has come around enough to turn them into torque.
If you've got good new stuff, the engine will live. If not, you'll probably get to enjoy a Rory Rodeo!
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I think the 5.0 blocks have had a bad rap simply because of the crankshaft used and the 50 oz balance issue. I have seen the block used with a neutral balance crankshaft, flywheel, damper, and live quite well above 600 hp and more with nitrous. Balance and harmonics are vital to keeping any block together. Lighter weight crankshafts and rods/pistons always help. The stock 5.0 crankshaft is not my idea of a performance piece, but it does work well to 6200 rpm for a cruiser. Girdles in valley was debunked a long time ago as not helpful. Joe-JDC
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Joe, while I agree that the 50 oz imbalance on the "5.0L" Mustang engines is not a good thing for higher RPM use, I would be very leery about trying to use a stock 5.0 block approaching anything near 600 HP, again, depending on the intended use. Several years ago, a buddy made me a deal I could not refuse, for his old 331 cube SB Ford engine. It had a stock 5.0 (hyd. roller) block, an offshore 3.25" stroker kit with flat top pistons, a moderate solid flat tappet cam, out of the box AFR 185 heads, and a Holley 650 on a Victor Jr. intake. On a buddys engine dyno, it made 485 HP, and in my 3050 lb 85 Mustang Stocker platform, ran a best of 10.28 @128 MPH, using my 4 speed Jerico, shifting at 6800 RPM, hitting 7200 thru the finish line. It ran perfectly for a couple of years, and at the end of 2015, I decided to freshen it up. Good thing! Upon teardown, #1 main bearing cap came split thru the middle, and noticeable cracks were found at the main bearing webbing. Granted, my 331 has a 28 oz imbalance, rather than the more desirable internal balance, so maybe with a zero balance the block would have fared better. However, after looking at another 5.0 block I had laying around, I decided to use an earlier (1974) 302 block a buddy had laying around. I don`t know how much (if any) stronger the 74 block is, but unlike the 5.0 block, at least the main bearing bolt holes and head bolt holes SEEM better, in that they are blind. In addition, my machinest buddy installed a main cap girdle, which will hopefully help a bit. I would have much prefered something like a Dart or World block, I would rather have put that money towards FE stuff! Again, on a street type application, with occasional WOT blasts, the 5.0 block would have been fine, but I tend to lean on my stuff a bit more than that.