...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!
...to 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