I did my Stage 2 without a torque plate and it has zero blowby after hundreds of passes. I did use zero gap CA rings, though.... All my others used a plate. It would be interesting to do 2 motors identical except the torque plate and test leakdown.
I am using iron heads. Well hell, orange crush head gasket sets are $110 each. And I would need one set for TP and one for assy. ouch.
No need to go through all that work when all you needed to do is just measure the cylinders with a bore gauge that has .0001" increments without the heads on and then with the heads torqued on with gasket. Have to flip block and take measurements by inserting bore gauge from the bottom side when heads are bolted on. The sbb that Mart mentioned only had a .0001" variance which is almost nothing that rings wouldn't even notice.( a .0001" variance can be from a speck of oil on the spot measured is how small .0001" is) If the OP did this test he may have saved himself some trouble if in the results were like the sbb mentioned above. Both engine blocks have blind holes which might be why the sbb 350 didn't move enough to be concerned about and why the BBB 455 cylinders might not move either?
I'm Not a machinist... I have seen oodles of blocks being honed, Never once have I saw a per say custom HG used for honing with a plate. I'm using OC head gaskets on my build, For honing we just used a standard felpro that was laying around. FWIW. I cant see why you cant use your old head gasket for honing... I sure others will say No you cant... Ask your machinist... Reality your building a car engine. Not a airplane or submarine. If it breaks down on you your on land. call a tow truck..
The old wisdom was "Iron heads = iron torque plate. Aluminum heads = aluminum torque plate." I don't know how applicable that really is. To me, ANY torque plate is better than no torque plate. The advantage to iron is that you can use any head gasket. With an aluminum torque plate, you need an aluminum-compatible head gasket or you risk damaging the torque plate. You need THREE head gaskets. One for the torque plate, two to assemble the engine. Pontiac has blind head bolt holes, anchored to the block walls and not the cylinder. Pontiac blocks move around like crazy when you bolt the heads on. I would like to see that testing done on the SBB. Call me Doubting Thomas. At absolute minimum, you'd want the fire ring of the head gasket used with the torque plate to be exactly the same diameter as the fire ring on the head gasket used for engine assembly. Ideally, you use the SAME brand/part number for honing as you do for assembly, because it's the head gasket (especially the fire ring) that transmits the stress from the torque plate to the block deck. But again, ANY torque plate and ANY head gasket is better than NO torque plate and gasket. When there is no torque plate available, a stack of washers for each head bolt hole, and a bunch of short Grade 8 bolts is better than NO torque on those bolt holes during honing.
You know, I made this plate to be used on either side. Far as I'm concerned, he can bolt it down one side, brinell away, flip it over for the other side and brinell that side too. I just NEED it to make one engine. I could just send it out and have it blanchard ground each use. My mechanic friend gave me a bunch of crap about making it aluminum and not steel. My thoughts were, it only has to work once and it is a hell of a lot better than not using it at all. Hopefully I can get the last of my parts and haul this beast into the shop in the next week or two.
I know the whole idea is to totally replicate as many variables as possable.......but think everytime it get torqued it will change some. look at connecting rods, they change every time they are torqued. Some of this sounds more like splitting hairs. I'm sure your plate will work better than no plate, better than a stack of washers, I would used cheap new or used gaskets.....cost you more the have that thing cleaned uo than gasket . And without gasket I would be more worried about the deck surface of the block b4 I worried about the torque plate
