We - collectively as a consumer group - have done this to ourselves.

      In this entire thread, this is the message that needs to be understood, and then acted upon by this very group.   

      Expecting that we as a society can continue in our current purchasing practices, assuming that someone else should shoulder the responsibility to fix everything gong awry, whether that be the Business/Retailer, or the Courts, or then even Government, is misguided, irresponsible, and the very behavior that these unscrupulous vendors, manufactures and even Countries, count on; which unfortunately seems to scratch the itch that American consumers sadly seem to respond to.   

      Didn't your parents teach you anything!   

      Scott.

................. just changed the 8" diff in my 68 cougar from a 3.00 to a brand new, built by a local professional, 3.55. Nothing else changed, but now there's a driveline vibration that wasn't there before.

     This scenario is not uncommon, as the demon is the fact that the drive-shaft is now spinning faster, this at any comparable road speed than as before, and the inevitable remaining imbalance in the shaft gains a value sum that becomes now noticeably felt.   

     Scott.

If that short turn is close to the valve, IMHO as a total amateur porter I think you'd possibly aggravate an already iffy flow condition by increasing the valve size.

     If 'just' increasing the valve diameter and incorporating a machine throat opening below the seat angles into the casting, then generally yes.  But again generally if one is incurring the effort to increase the valve size and this is with performance in mind some sum of porting/blending is involved which mitigates the negative, with the limitation then becoming based on the effort and capability of the individual, and/or the castings' capacity.   

The tongues raise the floor and give the air a better shot at the valve which would make the port work better for the larger valve area.

      Well, maybe; and it all sounds good, but it just doesn't always work that way.  Remember, the goal in port modification is to provide a greater effect of coercing vs. forcing the air to follow the path set forth by the port pathway, and sometimes this requires an influence upon the air column ahead of the the intended action so as not to grossly upset the continuity in that column in the greater ulltimate intent.

      As an example, though somewhat removed, and yes there are many influences at work, but just for thought:  For the most part, in time, a winding river will generally increase the arc of of it's turns, the river moving outward and exaggerating the radiuses (O.K. radii  ; and so remember one doesn't want to purchase the property "on the river" on the outside of a turn!  ); and haven't you always been taught that "water will follow in the path of least resistance"?   

      Scott.

       First, one must decide if there is enough remaining material for reasonably proper function.  Most of the "steel" drag brake rotors do not present adequate material thickness to permit anything more than a deglazing or a very minor cleanup cut.  Remember, that automotive braking systems of this nature are designed around friction and heat production, and it is the responsibility of the rotor (disc brakes) to absorb this heat as produced, functioning as a heat-sink initially, before dispelling it into the atmosphere; and if your already overheating the disc now, this causing the resultant warpage, then how well do you think they're going to work after the removal of any significant sum of material?   

       I my opinion grinding is the best way of servicing the rotor, and I have cut them previously utilizing our flywheel grinder, this which is designed for just such types of items, and is the equipment I would advise in the attempt for a reasonably proper outcome.   

       As far as for the localized hardness formations, yes is a concern, and this will be very apparent upon the cutting process (even more so particularly if utilizing a lathe and cutting tool) and if excessive the subject part should be discarded, as not only will the coefficient of friction and effectiveness in the act of braking function be affected, but also significant ductility in the metal is lost and this could lead to a catastrophic failure!   

       Scott.

     Lifters tending to swage in the block bores is not uncommon; this particularly with replacement lifters presenting a different external barrel shape (particularly the location and width of an oil belt-line or weight reduction relief band, and/or with camshaft lobes of different base circles and/or lobe lifts, all of which positions the lifters load surfaces on territory within the bores not as previously utilized.  Therefore with engine block prep work we always lightly hone (no, not a "ball-hone", with a proper honing mandrel) the lifter bores to remove deposits, knock down steps and burs, and if only to make more visual, imperfections that might be concerning; then measure (generally not having removed more than a tenth or two at the most from the bores' original diameter), and I even keep test lifter examples that I can drop through the bores at the time of this work just as a quick fitment double check before completion.   

     Scott.

...............but now as I'm mocking up a piston and rod on cylinder no. 4 , it measures .007 in the hole and when I used the same piston and rod in no. 1 it was .005 in the hole.  Is this acceptable ?

     Note that although the decks might be off by the .002", this observation can also be caused by the crank throws being off this distance;  but I don't think I'd loose sleep over it , as from Ford Motor Co. day one they would have been off by generally twice that, and that would have been a "good one"!   

     My intention is not to condone any instances of substandard workmanship, but rather provide a certain sum of perspective and reality to the situation.   

     Scott.

I use Strange Heavy Duty U-Joint Girdles now.
https://www.summitracing.com/parts/str-u1610hd

     This is some of the stuff that just makes me wonder, W.T.F.!   

     Let's say I'm the manufacturer of this product, and I need a part number to identify it, why would one select the number "U1610HD"?  I suppose the "U" indicates that it might be a "U-Joint" and the "HD" implies perhaps that it might qualify as being special "Heavy-Duty", O.K..   But why the "1610"?  You know that there is such a thing as a "1610" type U-Joint, maybe not so commonly used in the light automotive applications, rather larger commercial trucks and heavy equipment, but why not utilize the "1350" nomenclature which would aid in identifying the intended application and just reduce the confusion?   

     Oh, and no, this won't fit a "1610" joint ("1350": 1.188" & "1610": 1.875" cap dia.).   

     Scott.

   

     Perhaps this would be interesting for those whom are of the ability to utilize these, or else perhaps their just "Man-Cave"/"Wall-Hanger" stuff?   


https://www.ebay.com/itm/166639688877?itmmeta=01HSBZEW5R2GT60CKRR70HZ29E&hash=item26cc7fdcad%3Ag%3A09YAAOSwhsZl7SeU&itmprp=enc%3AAQAJAAAA4FSfPOXbMk1RjeJls6CC0jP6KmuUZ%2BNC2auAxI0JCiC%2ByYB2sb3qEbKjLPpLxeSeNJcz2fR1PR%2BhmLEETUx%2F%2BOO5kQrbVmepkaDr9JWY2e1FogZQvxkmTAcq%2B8zjIGKguHxJ3JfeYNSXb%2FvxCllzvbYkHwQ%2BlQpPUc85B5BCSv7XQV2fqJ0t1n8H44xcy8Rb%2FrcXAiYCGN3YeDXTB59Q0cfcfAj0uXUQHJagS%2FTSGPODmGA%2FaJew%2FMeLIk3FNhQMOTxdTZwtvGlgRTqKTHaPjuzaOYMuMg4HxQXkbkkJDAj3%7Ctkp%3ABk9SR4zDu__KYw&LH_ItemCondition=3000

     Scott.