piston quench/compression question

May seem stupid but I have a question. I found a set of rods that will work with my Ford combo which calls for a 4.5 stroke, 6.8 rod. I also found a shelf set of Diamond pistons that will be about 12.2-1 compression with a 6.8 rod. So, the rods I found are 6.76 length and are priced reasonably. Will they work and lower the compression enough? Wondering if it would be bad to have the piston that far in the hole. This is for a mild blown alcohol motor making max of 20 pounds. Chris

 

you can always put a little thicker head gasket on it and get the desired compression. so, that being said they should work just fine. you can always CC the deal and find the compression, thats how we like to do it. hope this helps.
Darren Russell

 

I thought about the head gasket thickness also but the reason I asked is because the rods I found are 6.76 and the pistons are spec'd for a 6.8 rod. Didn't know if it would hurt having the piston .040 down in the hole but I guess it wouldn't hurt since I need aluminum rods. Thanks! Chris

 

What we watch for is maintaining .055" clearence between the piston and the head.
So if the pistons are .040 down theoretically you could run a .015" gasket. i wouldn't run that thin because the thicker the copper the more irregularities it can mask. So in your case I would deck the block .025 and use .040" head gaskets.

 

Its an Eliminator Ultra block, 4.5 stroke, 4.5 bore. I need a 6.8 rod but found some 6.76 rods for a good price that I was considering buying but I guess I should just stick with the 6.8's to avoid any problems. Heads are Trick Flow A460 heads, 86cc. Thanks! Chris

 

Still don't have pushrods or head gaskets yet. I'm going to just wait and get the 6.8 rods and not worry about saving on the set I found, sounds like a few headaches will come up later. Thanks, Chris