If one is going to set up a B series DOHC Honda motor, I have some questions:

1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).

2) Can one replace the rotating assembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.

3) If this all works out, is there any need for modification to the block or the cylinders? Will the 2mm longer stroke affect anything?

4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotating internals versus GSR rotating internals?

5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.

What are your thoughts?

 

LS internals make more power partial due to the added stroke and partially due to the r/s ratio (generally lower is better for a little more low end power). The GSR pistons wont fit on LS rods without milling the rod or piston just a bit. In general for a car making under 250-300whp, OEM pistons are the way to go. They generally last longer and dont make as much noise.