was at a machine shop the other day under consideration as a place to get my spare block bored and honed and no torque plates were in evidence at the boring machine or on the block in position for boring on the machine(a SBC) Though i won't be using this engine for racing or other hard usage,i do want nice round bores-should i check out other shops to see if they use torque plates or is this not a big deal with a .030 over 350?

 

If other shops in the area use a torque plate you might as well do it. If you don't get it done it is not the end of the world. I've built a few engines without torque plate bore/hone and they have came out fine, held up to lots of abuse, and have good ring seal.

 

That is a critical step when it comes to 400's who's bores do move around alot.In any case it costs more because of a the labor involved.

 

I've never worried too much about the machine shop using a torque plate on anything I've built. I can't see it making a huge difference without tying the torque plate to another torque plate on the other side (simulating heads/intake) but then again I'm not a professional.

 

It's one of those reasons why 2 engines built from the same bill of materials don't run the same...

It duplicates the stresses and distortions in the block that bolting on the heads will produce, thereby making the pistons fit and the rings seal that much better.

On the list of block prep "details" that REALLY ADD UP in maximizing the result of a motor build, I'd put it right up at the very top; along with decking the block SQUARE and EQUAL.

 

Hehe-never thought about unequal deck heights,but yeah i have seen sloppy workmanship in SBCs beforeI might have the block decked if shop looks like a good one because even with normal original GM pistons,looks like they are sitting ~.030 or more down in the bore.

 

Decking.Use the parts stack method to add up to .040 squish/quench.SCR on iron heads of 9.5 or on aluminum 10.5 and dcr of 8.5.