why are block cylinders tapered

[Challenger340]

Found a cheaper machine shop that didn't use torque plates for boring and when I asked why? he said it's only if you want to squeeze the most hp you can from a motor. He didn't seam too concerned about not using them.  BTW I'm not building a bracket racing motor , but don't want a shop thats not paying attention to the thousandths  of an inch that blow motors.

It matter's not a Bracket RACE motor, or just a good solid street engine... that has best longevity and sealing over Time.
It may be helpful for you to simply google search "Why use a Torque Plate" for yourself ?

Knowledge is essential to good decisions, and at least you may then gauge for yourself yes or no as req'd for what YOU want.

[DanielRobert]

Thanks for the reply. I asked because I wanted real world advice. I coulda Googled the torque plate thing but I'm lazy and this site is easier to get live answers to and not an article to read. Better knowledge in my opinion.

[justcruisin]

I am far from an expert but my current engine was rebuilt to stock with a 0.040" overbore (no plate). After only 3000 miles I pulled the engine as i wasn't happy with the performance. Had a torque plate fiitted up to measure and the machinist claimed  0.002" out of round, and said the bolts were showing a bulge to the cylinders although I don't recall how much, he advised to bore it. I took the block back and measured the bores - perfect, then fitted up some RPM heads and measured from underneath, I got less than 0.001" out of round. Just a street car so I fitted the new pistons with just a light hone to the bores, JE file fit rings. After a thousand miles I did a cold leak down and was at 7% with 185psi cranking. If I thought it needed to be bored I would have the plate used though, If you are going to the trouble of boring it I can't see why you wouldn't.

[Bronzedodge]

Hot Rod ( I think) did a more recent article in torque plates where they honed a block without plates and illustrated the distortions.  It was a noticeable difference.

[Challenger340]

I've personally Bored/Honed probably somewhere in the neighborhood of 600+ BB Mopars over the last 40 years ? Race... Brackets.... Street..... even Industrial applications.
And over the last 25 years I've had the opportunity to actual DYNO test the finished products as well ?

I would not even think about NOT using a Torque Plate on a 440 Mopar ?... even it if was just for my Wheel-Barrow !

As is said... "excuses satisfy only those who make them", so attach whatever rationale YOU want in justification as to why YOU don't need a Torque Plate while Boring & Honing YOUR Engine ?

But that said...
all I am saying is this.... Don't anyone tell ME there ain't a significant difference in Engine Blow-by, sealing, power and longevity in ALL applications.
Unless of course,
you yourself have also Bored & Honed 600+ BB Mopars over the decades, and DYNO'd lots of the results..... in which case we can then agree to dis-agree.