Hey guys, I am in the process of building a GSR motor for boost. Its going to have Wiseco 81.5 pistons, eagle rods, and stock sleeves, headstuds, and main studs. The bottom end is from an LS motor. Im looking to make in the area of 500whp at around 22ish psi or whatever gets me close to 500. my question is, wil my bottom end need balanced? i know there are several guys on here with high horsepower Hondas. What would you recommend? Thanks! -Micah
Definitely! Get the entire rotating assembly checked AND balanced. I am assuming you already had the block bored/honed for those specific pistons right? If not, do it, then balance and you’ll have a durable setup.
Do it.
what rpm do you plan on hard limiting at? its definitely worth it… go with the lightest crank and flywheel you find find 
Might as well gram match the rods/pistons too while your in there…
I do have the block bored and honed. And i plan to take it to 8000 rpm. I have an 8.5lb flywheel; will an LS crank be cutting it for “lightest crank i can find”? Im on a tight budget but also dont want to scatter my motor. So it would seem as if balancing is the way to go. Ill give the machine shop a call today. Any other suggestions? Jason, what is gram matching?
uncut oem b-series cranks are extremly well balanced from the factory, but balancing is cheap insurance and a good piece of mind! stick with the ls crank it will give you a longer stroke/ more displacement. If u are using a gsr block with an ls crank you will have to remove the oil squirters so your piston skirts do not contact them and plug the holes. Golden eagle makes a plug kit. Gram matching is making sure all the pistons/rods weigh equally the same. I dont have any experience with eagle or wiseco but i know my cp’s were within .1 off the shelf. Use b16 rod bearings beacuse the ls rod journals are wider than gsr and the ls bearings are not as durable as the b16’s. Use gsr main bearing with the ls crank. I reccomend using oem bearings but sometimes they are hard to decode sizes without a chart.
Heres the chart u will need
Main Bearing thickness by color
Blue 2.013-2.010 mm 0.0793”- 0.0791”
Black 2.010-2.007 mm 0.0791”- 0.0790”
Brown 2.007-2.004 mm 0.0790”- 0.0789”
Green 2.004-2.001 mm 0.0789”- 0.0788”
Yellow 2.001-1.998 mm 0.0788”- 0.0787”
Pink 1.998-1.995 mm 0.0787”- 0.0785”
Red 1.995-1.992 mm 0.0785”- 0.0783”
Rod bearing thickness by color
Blue 1.510-1.507 mm 0.0594”- 0.0593”
Black 1.507-1.504 mm 0.0593”- 0.0592”
Brown 1.504-1.501 mm 0.0592”- 0.0591”
Green 1.501-1.498 mm 0.0591”- 0.0590”
Yellow 1.498-1.495 mm 0.0590”- 0.0589”
Pink 1.495-1.492 mm 0.0589”- 0.0587”
Red 1.492-1.489 mm 0.0587”- 0.0586”
def balance it…eagle rods are cheap for a reason they are very very close in weight but they can be better. I alwasy have it done no matter what…i like to do things once…but it is up to you
good lucj
Just get a Set Of ACLS There are Like OEM greens. I havent came across a motor yet that they dident come within Spec.
Thanks for all the info guys! Hopefully ill be ready by the next FLD’s at Beaver Run!