JadXtreme

The 6.0 L76 in my G8 is making some ominous noises, sounds like it's knocking. I hate it but at least it gives me an opportunity to go thru the engine and do with it what I want.
​​​I want to make this 6.0 into a 421 cubic inch engine (Pontiac 421 HO throwback). I plan to max the over bore to 4.030 and give it a 4.125 stroke to accomplish my goal. Will do my own port and polishing of the heads and upgrade to an LS9 set of valves. I may use a stock LS3 cam with 1.8 rockers not not 100% sure on the cam choice as of yet.
Right now, I'm just in the planning stage and will be slowely gathering parts I need to do the build.
I will start by pulling the engine out soon to make sure the block isn't trashed and can be bored and clearenced for the long stroke.
Also will be trying to keep this on a strick budget and will be doing all the work, minus machining, myself.
This isn't a lofty goal with this 6.0 block is it? Also if I can find a wrecked 5th gen Camaro SS, I'll use the LS3 for the base of the build. Just depends if I can get one or not.
​​​​​The goal of the build is to have a stock looking, mostly stock sounding, stock driving G8 that the wife would feel comfortable driving. But when you want the power, it's there.

Patron

The correct pistons and engine build process will do well. 4.00 crank is even better not as much side load nor pulling pistons down as far. For most strokers 6.0 rod should be used to have a taller piston. Correct pistons and tapered bore is key.


*Oh if it's a aluminum block same thing goes sleeves are a hair longer. Diet Coke did a 430 Ls3 with the 4.125 crank. Did say a few things about he wouldn't have run it but rather a 4 inch crank. It can work just gotta have a competent short block builder. Most will recommend staying at 4 inches. 5.8 long sleeves help but add cost.

Patron

http://www.yellowbullet.com/forum/sh....php?t=1546674

64post

iTrader: (5)

Forget the .030 over part if it's a true L76 aluminum block.

KCS

iTrader: (20)

Tapered bores are bad, I think you meant chamfered.

6" rods are a bad too, not sure who you got that from but you must have misunderstood. A 6" rod is going to pull the pin down further in the bore for the same stroke, as well as cause the crank manufacturer to have to cam cut shorter counterweights, which could make it more difficult to balance. Most builders will use a 6.125" rod because it just makes more sense.

64post

iTrader: (5)

An LQ block bored .060 with 4.100 stroke would be a better, safer combination IMO and would put you just over 421c.i.by 3

JadXtreme

Yeah I want to keep the aluminum block. Not making a race car. My preferred base for the build is a LS3 and I may hold out till I can find one.

Patron

KCS your correct on the wording for the bottom of the cylinder bores. But on a 6.0 rod that would make the piston pin move down some to not have it go into the rings. I noticed it on the Lsx 454 6.0 rods are used. Noticed a few other larger than 4 inch cranks using 6.0 rods.

MuhThugga

I'd forego the 4.125" stroke in favor of a 4" stroke. Your engine will be much happier and I doubt you would even notice the cubic inch loss.