mikelopez

So I have a ls3 that needs a rebuild desperately and wanted to do a 416 stoker on it. Was gonna do n/a but now looking at doing the apg tt kit in the future, will stay n/a for a while. So should I have my cr low already to begin with? Or have it setup for na then change out pistons when ready for boost? I was looking at the Smeding performance 416 kit the 1300hp rated kit, they told me to go with the 15cc pistons for boost. New to ls building and wanting to do it myself as I’m somewhat mechanically inclined

The BallSS

iTrader: (9)

Compression is going to depend on intended fuel used, pump gas I'd stay around 9.5:1 and E85 I'd stay around 10.5:1.
Build it for boost up front, you won't really notice it much.
I drove my last car for a year N/A but setup for boost and it was still plenty fun, was just more fun when I put 14 lbs. on top of it with a single 7875.
Put a boost friendly cam in it too so when the time arrives to add boost, you don't have to open the engine again.
Just my $.02

mikelopez

yeah I’m really just gonna stick to 91 pump gas that’s the highest around me in SoCal, could probably even get 100 octane at my local gas station. If I do the 9.5:1 how would using e85 differ from the 10.5:1

The BallSS

iTrader: (9)

E85 has a higher ethanol content than pump gas so it's less detonation prone as well as having a cooling effect on combustion so you can push it a lot harder.
I'd stick around 9.5:1 for straight 91 pump, you can run 14-16 lbs. reliably with good turbos then splash some race fuel in there if you intend on racing the car hard or dyno pulls just for a little safety.
Race gas has gotten stupid expensive and a barrel of E85 runs under $600 so if you don't mind having a drum in your garage that is an option, you could also install a methanol injection system as well.
E85 will allow you to push a lot more boost but a 416 with a good pair of turbos will still make a lot of power on pump gas at 14-15 lbs.