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Thread: 351w ?'s

  1. #1

    Default 351w ?'s

    I traded my falcon I had for an 82 Mustang GT that had a 351w in it. The kid lost bearing messed up crank and took chunks out of bottom of cylinder walls. Guessing that block is **** now. I have another engine that I am going to be getting looked at and checked out to see if useable. The car ran in the 11s I was told but can't verify. The engine had windsor jr heads on it with comp 1.6 rockers and springs set up for comp 35-250-4 cam and a vic jr intake. Has 4.10 8.8 in the rear and a c4 tranny.


    Questions are....


    1. Since engine is being rebuilt should I stroke it out to 393 or leave it stock?
    2. If build back to stock should I use the heads as they are or should I have them ported?
    3. If I go stroker (I am on a budget) would the heads be good the way they are?
    4. I need to run on pump gas so how much dish would I need on pistons?Name:  20180324_170743.jpg
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  2. #2
    FEP Super Member xctasy's Avatar
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    Don't junk any 351W block...reclaim it.

    Crack test the cam, and ensure its not bent or impacted.

    Decide on budget, then decide on better than stock 351W rod bolts so this doesn't happen again. The block, rods and stroker upgrades are going to force you to consider ensuring nothing like this happens again.

    All aged Cast iron has cracks, just like a cement floor or wall in a building does. Everything cracks. As long as the cracks aren't propogated through the bores, mains and camshaft tunnels, and it holds kerosene in the oil and water cooling spaces under 3 bar or pressure for a day, your good to rebuild.

    Aftermarket blocks have no engine numbers, and although they are wonderfull, if your car sees street duty, then it'll most likely need some kind of not stollen, factoy engine no. identifier, and only a stock 351W block from the Windsor Ontario or Cleveland plant can do that for you. The aftermarkets have no EO interchange like you get if you use a stock production 351w block.

    Reclaiming process.

    Pop the cam bearings. They have to be removed to check if the block is free from hairline cracks at the oil galleries.

    Put the damaged block on a Vibrating table, and shake it for two hours. This is a shaking device used normally for soil compaction Laboratory tests, and is great for items around 165 pound or less, perfect for a cylinder block. It can be used to stress relieve the block. All good engine rebuilders know where to get access to one.

    Then Magnaflux and pressure test the block for cracks with kero with a little fluroscene die tracer. If thats good, chemically clean the block, then apply Die penetrate, and black light it. All cracks show up. If okay, have the block smoothened at the chips, then look at a resleeve the two cylinders.

    Have the block Gyptol coated after heat and quench seasoning.

    Cap walk and poor rods are common on rebulit two bolt 351W's. The 351w is a truley great thin wall engine, much better internally than the 351C and 302w's.

    A 351W block that checks out okay for crack testing is fine to use. No strokers unless the block is 100%. If it is go ahead.

    Do three things.


    1. good Crank girdle requires a better capacity sump, like Milodon 351W Fox swap pan and

    2. DSS make a perfect girdle and windage tray (MSS1020....351W/5.8W Production Block)

    and

    3. Valley Girdle Pro VG351w makes upper ties.

    Internally balanced Stroker cranks are all for specialised stroker Race Clevelands or Windsors, and rare and expensive, and often have 2.75" main bearings, not the stock 3" mains. 400 Ford cranks aren't anything special, and are ex 400 Fords with 28.2 Oz unbalance. The aftermarket make Scat, Eagle and some other brands with 3.85 or 4" stroke cranks with 28.2 or 50 Oz unbalance.

    I'd personally buy the fully balanced zero balance 351W stroker 408 or 393 crank, and have the serpentine pulley zero balanced, and use the F150 4.9 zero balance flexplate if at all possible. Get a balancer with a removable weight. The cost is goning to be a rebalance fee and mallory metal check weights. The old Ford SVO cranks like the 351c M-6302-E351 steel semi finished NASCAR crank, they were internally balanced and lighter than the externaaly balanced 4MA or cast cranks, even the aftermarket 3" main stroker iron cranks. They are around, and are bullet proof, with a stroke capacity of 3.60-4.0", and they You can have them welded up to 3" mains, they are 2.75" mains normally, but can be offset ground to a Chevy Big Block 2.1" crank pin rod

    The money you spend upfront prevents buying a heavier casting block, like the World, Dart, or Ford Performance block.

    The crossover point is about the time you have more than 8 grand of your own money in the engine. Then its time to get a 3 grand aftermarket block.

    For me, the old iron thin wall blocks start to give up the ghost when the rod to stroke ratio is below 5.955/3.85, or 1.55.

    The 351w rods are pretty good, as good as 5.78" 351C rods or the nearly the same as Windsor 6.01" Aussie "reverse stroker" 1971-1983 302C rods.

    My fourth step would be to get some better rods.

    4. Read th this http://www.dragzine.com/tech-stories...-351w-stroker/

    OEM style I-Beam rods are great for lower RPM, if preped and with ARP bolts.

    Lastly, anytime you have a fixed CFM head, the maximum rpm point is decided, and it varies not so much by cam duration choice, but by the CFM at peak valve lift.

    Your heads quickly become too small with a cam devised for a 30 thou over 351w with a cam that suits those allo heads ans that capacity. Just adding 36 extra cubes will drop the peak power band down below 4500 rpm with most 393's. With that little engine speed, its hard to get more than 350 hp. You could get that with the same heads on a stock block 302 , stroked out 331, or 347 stroker.

  3. #3
    FEP Super Member cb84capri's Avatar
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    Great link for figuring out engine compression ratio:

    http://www.csgnetwork.com/compcalc.html

    Those heads should have 58cc combustion chambers.

    Those heads will be kind of small on anything larger than a 351w. Since I have those heads, I would suggest taking them apart and checking them out before planning a build around them. Mine apparently went to hell and back before I got them, and I had to have bronze valve guides put into mine. The cast guides were pretty torn up, I don't know if this is typical of these heads but it's worth checking out. Also, if the springs are the World Products ones still, they are junk. After only a few summers of driving, my seat pressures were dangerously low on my replacement springs I bought directly from Bill Mitchell Products. If memory serves, I paid to have my spring bosses resized so I could run a quality PAC set of springs when they were freshened up for my 347.

    It sounds like you're pretty budget conscious about this build, so I would suggest sticking to a stock 351w game plan with your current heads. Buy a set of forged Scat I beam connecting rods for it, quality forged pistons, and some ARP fasteners. If you want to spend some money, get some Howards Cams link bar hydraulic roller lifters and put a roller cam in it. Otherwise I would go to mechanical flat tappet. I would avoid the F4 roller block altogether - they have a tendency to crack. I think a hydraulic flat tappet camshaft is asking for a camshaft failure. For what you spend now on the roller setup, you will spend over the years on special oils or additives to keep the flat tappet alive. But if you want, I will give you my old mechanical flat tappet CompCL31-334-4 camshaft and their direct lube lifters. Stroking this thing is going to add a lot of cost, and personally I would rather run a stock crankshaft than a cast Scat crank.

    Porting the heads is something you can do on your own if you feel like investing the time (and believe me it takes a lot of it). I could go on and on, but look up headbytes porting on youtube for a lot of pointers. I would concentrate on doing some nice bowl blends, and really smoothing over the exhaust ports and cutting down the guide bosses in there to get them out of the way. If you have BBK headers, you'll want to grind back the big welds inside of the primaries, too.

    Cale

  4. #4
    FEP Senior Member Matt J's Avatar
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    Part of your decision needs to be what you plan to do with it. If it's just for street use, then you can build a stock 351 to give you all the power you need without a ton of modification. If the story is correct, and the car was running in the 11s, that's pretty fast for the street already! Machine shop work is very expensive, and you might do better by replacing top end stuff for the same money and still get you where you want to be (if it needs it, sounds like you have some good stuff to bolt on from the old block). It also makes things easier to work on later, in terms of finding parts. If you want to run pump gas (I read that as "regular" gas), keep an eye on what your modifications will do to compression ratios.

    Oh, if it doesn't have them already, you'll want subframe connectors with that much power under the hood!

  5. #5

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    I have this block to send off and get checked out. If it is useable then i will just build it to 357 and work from there. I will be getting subframe connectors put in soon. Gas i think is usually 92 maybe 93 but its limited around here. The heads will be getting checked out at same time as the block. I was told had springs swapped to match the cam so i will have those checked out also. Do i need the forged rods if i used the truck rods with arp bolts? As far as cam if i swap to roller and retrofit this block then what cam suggestions do you have?


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  6. #6
    FEP Super Member cb84capri's Avatar
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    For what you'll spend on connecting rod bolts, having the used rods resized, and all the cumulative wear that is already on those old rods... $300 for Scat I beam rods that have ARP 8740 bolts in them and are ready to go is money well spent IMHO. I wouldn't use the block pictured in your first post.

    Cale

  7. #7
    FEP Senior Member droopie85gt's Avatar
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    I bet if you look around on craigslist you can find a 70's or 80's 351w block or shortblock pretty cheap. I found one that was reman and has less than 2000 miles on it for $300
    1985 GT, Sunroof, 5 Lug, Rear Discs, 01 Graphite Bullets, 88 forged piston shortblock, 2.02/1.60 Alum heads, Weiand Stealth, Holley C950 TBI, BBK Long tubes

  8. #8

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    What is considered a good set of forged pistons? Any cam suggestions?

  9. #9
    FEP Super Member erratic50's Avatar
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    Just about any properly fit forged piston is a good piston. Chrome rings are money well spent too on a street motor. TRW forged is what the good years of the ol 5.0L HO motors had...

    I would learn the physics of ring velocity in feet per second when assessing max RPM at a given stroke.

    hint - when using a stock style piston, ring, and rod package then you start running into undesireable forces and velocity around 6000 RPM with a 3.4” (342-347) stroke. Heading there with a stock bottom end 351W is asking for trouble.

    Stronger cranks, rods, istond, rings, and balancing make well north of 6000 a worthwhile and relatively low risk endeavor.

    Same FPS math applied to a 3” says 7000, 3.25” says 6500, 3.4” 6000, etc.

    Now figure your CFM on the intake side vs your CID. A 302 with 230 CFM revs to 8700 before running out of air, 331 to 7400, 347 to 6750...... and so on.

    There are many documented examples of 408’s with AFR 185’s and a good intake making north of 600HP.

    As for compression ..... on 91 octane I’d shoot for 10.5:1 and no more than 11:1. Detonation will totally trash a motor so know the signs.

    Injecting or jetting for E85 can pick up as much as 15% more power via higher octane. It requires 35% more fuel and liquid does not compress so your cyl pressure goes way up which makes more power. It also allows for more timing advance.

    good luck with your build.

  10. #10
    FEP Super Member cb84capri's Avatar
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    To get a pump gas friendly 10:1 compression with those iron heads, I would have the block 0 decked for these pistons:

    https://www.summitracing.com/parts/s...6f30/overview/

    You can use either Fel-pro 1133 MLS head gaskets, or Fel-pro 9333 depending on what you want to spend.

    If this is primarily a street car that sees occasional strip, I would ditch the Victor Jr in favor of a Professional Products Typhoon and use Fel-pro 1262s3 intake gaskets. If you don't buy the s3 version, you will have problems. The 1250s3 is very close in size to the Windsor Jr port size, and could protrude into the ports when the manifold is tightened down.

    In this combination I'm proposing, this is the off the shelf camshaft I suggest:

    https://www.summitracing.com/parts/c...view/make/ford

    It will be a lot of fun on the street. Anything that costs more than that, I would call up a company like Bullet Cams and for $400 get something custom ground for your application. If the strip is more your thing, a dual pattern will likely net you better track times. Also, use a standard volume Melling M83 oil pump. There is no need for a high volume pump in this application.

    Nice looking car btw!

    Cale

  11. #11

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    Got bills wife wants paid off and when your married to a midget you got to chose your battles lol. So just need engine put back together to get car running so I can at least drive it to and from work every now and then. At the end of the year I get a pretty decent bonus and I will be using most of that to build the engine. That's where I am at right now kinda suck but it's life.

    If I just put it back together the way the kid had it for now if I don't smash the pedal all the time right. Do any of you see any issues with this and is there anything you suggest I get done when I rebuild it to help with longevity or performance?

  12. #12

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    OK wondering if I should keep the heads or sell them and use money to purchase new ones? If I sell them, what is a good price for them with the cam and rocker arms?

  13. #13

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    What are the procomp 3037 heads like? There is a set near me.

  14. #14
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    Quote Originally Posted by KrystyonWayne24 View Post
    What are the procomp 3037 heads like? There is a set near me.
    I have no hands on experience with the Pro Comp heads. From what I have heard they are cheap hit or miss Chinese heads.
    '89 XR-7 5 Speed
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  15. #15
    FEP Senior Member droopie85gt's Avatar
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    I've got a cheap set of heads....They were called PBM Strike Force...210cc 2.02 1.60. They actually have been pretty decent. No idea on flow numbers, but I picked up .7 in the 8th when I changed from E7 and shorties to these and 1 3/4 bbk long tubes.
    1985 GT, Sunroof, 5 Lug, Rear Discs, 01 Graphite Bullets, 88 forged piston shortblock, 2.02/1.60 Alum heads, Weiand Stealth, Holley C950 TBI, BBK Long tubes

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