Stock Crankshaft Strength

**z28misfit** · 04-18-2007, 04:10 PM

Just trying to get a good idea of what people are pushing their stock cranks to. I've really been trying to narrow down what I want to do to my stock bottom end before I go purchasing heads and a D1-SC procharger. I've been thinking about getting lower compression forged pistons and some forged rods. Now, I would really like to make over 600rwhp, so now my question is Can the stock crank handle that? If not for the $ I may as well skip the whole bottom end and just save up for a 408 shortblock assembly. I don't feel like putting a $3,500 or so stock cube rotating assembly or even a 383 kit in it. If I'm going to bigger cubes I want 400+ cubic inches. Sorry if this post is vague , but trying to get others views and experience before I go and get rods and pistons and skip the crank and find out I was a complete idiot for not just doing everything.
Mods as of now on the engine are G5x4, lt's, FAST 90/90,ory, underdrive,85mm maf, lid.
I was just considering using my stock bottom end for now and just go ahead and run the TFS heads with a D1-sc. I just thought if I could save the bottom end from flying apart I may as well strengthen it.
Any input is appreciated in advance!!

**Mr. Luos** · 04-18-2007, 04:47 PM

Stock crank is solid.
It is the rods and pistons that can cause problems.

**Hi-Po** · 04-18-2007, 06:37 PM

But for 600 rwhp? I would trust the stock crank... for alittle while. I wouldnt skip the last piece of the "chain" IF I was building the engine.

**z28misfit** · 04-19-2007, 11:40 AM

Originally Posted by Hi-Po

But for 600 rwhp? I would trust the stock crank... for alittle while. I wouldnt skip the last piece of the "chain" IF I was building the engine.

I understand what you're getting at. I was thinking the same thing, just if I found out that the stock crank is plenty strong I would consider leaving it. This is kind of a tough decision, because 1. I could test my luck out and leave the whole bottom end stock. 2. For the $ of a stroker kit, I may as well just save a couple more $'s up for a 408 shortblock or something from LME. Trying not to jeopordize myself. End up going with heads and the procharger and 2 months later the bottom end decides its had enough.

**FASTSS** · 04-19-2007, 12:40 PM

Originally Posted by Hi-Po

But for 600 rwhp? I would trust the stock crank... for alittle while. I wouldnt skip the last piece of the "chain" IF I was building the engine.

With 600 hp you will not break it. There have many that have lived under 1000 rwhp, 600 will not hurt it.

There has never been a documented case of a stock LS1 crank breaking from too much hp.

**z28misfit** · 04-19-2007, 12:50 PM

Originally Posted by FASTSS

With 600 hp you will not break it. There have many that have lived under 1000 rwhp, 600 will not hurt it.

There has never been a documented case of a stock LS1 crank breaking from too much hp.

That's what I thought. I believe I saw something on TV one time, and they had a program on GM's LS engine family, and I thought they said something about the stock cranks being very strong up to 900hp capabilities. But that was a while ago that I saw that. If you look in that book on "How to build LS1/LS6 engines" it says that the if you're looking to make more than 550hp then a different crank should be considered. I thought they underrated the stock crank at that power level.

**Hi-Po** · 04-19-2007, 08:25 PM

Originally Posted by FASTSS

With 600 hp you will not break it. There have many that have lived under 1000 rwhp, 600 will not hurt it.

There has never been a documented case of a stock LS1 crank breaking from too much hp.

Well, I guess I agree with you. I dont have any info of stock cranks breaking ethier. I just think, if your gonna get 3/4 of the reciprocating assembly forged and bullet proof, why not get the last piece. But no doubt, there are many, many guys and girls s/c on stock cranks for sure. I agree wit hothers for now, Your young, got a nice car and solid engine. If I was in your shoes I would probaly do the same thing. Good luck ethier way

**bluethunder2** · 04-20-2007, 06:47 AM

Stock crank will be fine for over 600hp. I'm over that with nitrous. Your blower won't hit near as hard as my nitrous does. You should be just fine.

**z28misfit** · 04-20-2007, 10:09 AM

Thanks everyone, hopefully more people keep posting up what they have experienced with stock cranks.

**z28misfit** · 05-08-2007, 12:28 PM

Like I said before, thanks for the input from everyone, but I decided to call it quits with the motor for now. The car runs pretty solid the way it is with stock heads. I think my only upcoming engine mods are gonna be better pushrods and more than likely Harland Sharp rockers. I didn't think my taxes were going to be as bad as they were this year so it kinda pulled the plug on any plans on modding the motor.

**Spaz** · 05-10-2007, 11:49 AM

i split my crank in half before i had anything with the acception of free mods done to my car... i got luck and it spun around and caught again enough so that i could drive home from the track... worst freakin ride EVER...