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can anyone give me an opinion as to if this 400 FMX block that i can buy is even worth me buying. will a machine shop be able to even clean this block up so that i can use it..also will these piston cylinders clean up or will they need replaced?  the person wants 450.00  is this way to much56429268_566269067218770_1961544021151055872_n56584307_413908452503034_4837557966271938560_n57154561_330444637821991_7097110556703719424_n87023681_10215735307605436_2665323512666783744_n107869418_771621696912193_6310705085931102430_n


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Last edited by sonny
Original Post

...There are a couple of books with rebuild articles and dyno results. Look up 'FORD V-8' by Monroe. I am looking through a second manual 'Ford 351 Cleveland Engines' SA How-To by George Reid. Why is a 400 in this book, because the only difference is it's a "Tall Deck Stroker Cleveland", that receives No Respect!. (and probably carries different size bearings.

Some Dyno #'s.

Max. HP 675 @ 7000 RPM, Max. Torque 571 @ 5000 RPM

'Stock' Rebuild Useing: Flat top pistons, 9.5:1 CR for 568HP, (with 10.5 would break 600HP) and that's with stock 2 bbl heads. Imagine the Cleveland 4V Heads on this block, for 'Breathing'.

 Downside...2 Bolt Mains. The 'Weight Factor'. NO Respect because the 400 was first 'Issued' with 2V Heads, 2V Manifold and a 2V Carburetor !!

All, correct Me if I am wrong....I believe the Bellhousing Bolt Pattern Remains The Same ?? 

Most Shops will Know what they are doing with this Block. When You get it Back, it will look brand-new.  To Obtain Equal Big Cubes and Big Stroke. You will have to decide whether to Go Stroked Cleveland, which will Weaken it, where the 400 is already there and remains Strong.  We All Agree More Power Costs More Money. How Much do You wish to spend on this Engine? With the Correct 'Matched' Pieces and A Experienced Machinist, this Block could become a real 'Power Monster', In My Opinion!! You Would Surprise a Lot of Competition, AND Sustain It, for Hours! Or, just Taking Pink Slips! And the Engine would be Precisely Balanced (in and out), and rebuilt with a Lot More Attention and 'Love' than the 'Factory' had Time to give it. If You can Believe what I Read in this Rebuild Test article, they Spun this 400 Engine up to 7500 RPM for 664Hp 465Tq.

I Do NOT know if all 400 Blocks, are what You described as a 'FMX' 400.  

Others with Experience Building these Engines are sure to Contribute Soon. Good-Luck with It! answer Your first question...YES! the Pistons Will Have to be REplaced, because, to 'Clean-Up' the Cylinders, takes a 'Re-Bore', a Re-Hone and a Fitting of Larger Pistons. The fact is EVERYTHING Must be Inspected, checked, reconditioned, replaced, balanced...Polished?! 'Blueprinted'!

if You DIY, working with the Machinist, Shop doe's All the Work. You furnish all parts...$2500.-$5000. Shop does all work, and gathers parts for You (and marks them UP!)...$6000.-$10000. and More. Power with Precision Equals $$$$$$$$$$!!  "How fast do You Need to Go Fast, And How Fast??" MJ  

Last edited by marlinjack

...I can't tell if Your Block is Sound, by a picture!! Only a Machinist, who is experienced with Inspections and Sonic Testing, can answer for You, And Not Before. I can tell You All the Rust will be Gone....Like I wrote, earlier, You'll get the Engine Block back, Looking Brand-New, and Machined More Precise than the Day it was Born.

Call Around for 'Performance Machine  Shops'. They have the Answers Waiting for You.


Last edited by marlinjack

sir i am sorry that i worded my question to make you feel like i was asking you to tell me the block was 100% because it was not. i just wanted some experienced people on this site to tell me if something stood out really bad with this block. please except my apology if i came off like that because i really do thank you for your infomation 

you can drill & tap 1 of the 2, the other is not in the correct location.

passenger side US, IIRC these 2 are correct


drivers side US see where the rearward boss is out of place?


FWIW IMO $450 is not too much for a usable FMX block but the example you've found is rough, needs to be evaluated before it can be determined usable at all even with some repair. with that much rust / water damage i'd be concerned about cracking / freeze damage and excessive pitting.

$450 ? it's only money. they're out there, a couple on the FB page recently are not selling for a little more but much better condition going in


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Last edited by 4vandproud

thanks sir for your input and you will never know who much i appreciate it. i really have no knowledge of the fmx block per say. i just have a 351 Cleveland and thought if i every came across one i would put my D1AE-GA on it with some other upgrades so i could tell people i have a 400 which they think is a turd ,then when it runs at least with them or maybe beats them they will be scratching their  heads.i really didn't know about the motor mounts but i should have



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