been side tracked for too long time to order pistons. i have a tall deck 59deg r3. i have a billet 3.55 stroke crank and i have too sets of rods.first set of rods carrillo 6.525 lgth .927 pin 2.1 big end 800grms second set k1 6.123 .984 pin 2.125 big end 720grms. should i grind the crank to 2.100 and use the carrillo rods with a 1.28 compression height piston or go with the k1 rods with 1.680 comp height piston. the motor is going in a dart for the street with procharger 8lbs boost port injected efi and mild roller cam .525 lift 230 duration .050

I would think that you'd want to get the compression height down. You'll be limited in compression ratio, and you might need to get the piston down in the hole (or a big dish) to get there. Putting the pin up high might prevent that?

Call whoever is going to make the pistons and let them decide. That way you don't screw yourself on accident.

I am just guessing that you will not want to push it on the compression height with boost.

the car will be my daily driver in good weather not raced every weekend the engine will have 10.5-1 compression, aluminum heads boost shouldn't be an issue with 8 lbs max.on the street the engine will rarely see boost and only start to see boost above 3000 rpm with a standard transmission.

Hope you don't want to run that on pump gas.

Yeah 10.5:1 won't fly with 8psi on pump gas...

Mine is 9.2:1 (iron head), and I could only get 16 degree's of timing into it on E85 at 12~13psi...

with water/meth injection and the fuelinjection it should be fine at 10.5-1 the question was about the connecting rods and pistons. would you run a heavier rod and light pistons or the lighter rod with a heavier piston?

I would run k1 rods and large piston ch.

Good luck.