jasonprobasco

I may have a chance to pick up a bare LS3 block cheap. I've been considering a stroker for my car and I'm looking for some input. I'm leaning toward a 402 LS2, but a 427 is much more appealing. I know I can get a stroker kit for an LS3 ,4.065" bore with a 4" stroke to make a 418 or 4.065" bore and a 4.100" stroke to make the 427. Although, from what I've read on CF that stroke seems to be less favorable, and I'm not trying to slam anyone with that stroke, I'm sure it works fine. My question is has anyone bore the LS3 to 4.125", the bore of the LS7. That combined with the 4" stroke will give me the 427 I'm looking for. It would require boring the block .060"...is that too much? I've looked for any info on a LS3 427 that this forum has to offer and there doesn't seem to be very much. I appreciate any info I can get.

BTW...I don't have the money for an LS7 swap. I know that'd be the best way to go.

carlrx7

its been done.

tjwong

You can resleeve the block to get the 4.125 bore then use a 4" stroke crank of your choice to get the 427. Then all you need to do is to decide on which heads. A good alternative and relatively inexpensive is a set of the CNC ported LS3 heads and a LS3 intake. It will make tons of torque and power. I recently installed a 418 LS3 into a newer C6 with the same heads and it made excellent power and torque across the board.

LS1LT1

Personally I would only go 418 (416?) with the LS3 block, I think the rod angles generated by the crank needed to bring it to 427 are a little much. Though it will work.

02gt350

i have an LS3 416....427 has been done out of a LS3, but has its issues...i have done the research

If you want a 427, stick to a LS7 block.

Tavarez

I don't understand aren't they basically the same block? There are ls2 427's all over the place that are resleeved and stronger than an ls7 427

LS1LT1

Yes, the LS2 and the LS3 blocks aren't all that different in basic design but the LS3 does have the larger bore of course making it an extra 12 cubic inches closer to that magic 427 number than the LS2.
But I think what '02gt350' was referring to is what it takes to get to 427 when starting with an LS3 (or LS2) block. And as far as sleeving goes I don't anyone here even assumed you were referring to sleeving as a means to get there, just using a new crank (4" stroke) in an otherwise stock LS3 block which is how most now build a 416-418.
Sleeving is whole 'nother approach.

LS1LT1

I don't think that can be done safely, might thin out the cylinder walls/spacing too much.

1.8t

Agreed. Go 418 if your staying n/a and if your planning on a power adder, go with the 416

02gt350

?????????????

02gt350

call LME or Scoggin Dickey......they can tell you all the answers to yoru questions

0Jon@RedlineMotorsports

Incorrect. adding a 4.0 crank to the stock 4.065 bore will yeild 415 cubes.
A 4.1 stoke (which is too much IMO) will yeild 426. We don't go bigger than 4.0 in our LS3s

Yes, it absolutely is too much

Chris@East Coast Supercharging

If you have your heart set on an 427 use the LS7 block, if not you can easily do a 416-420 cu with an LS3 block. I would also stay with a 4 inch stroke no matter which block you end up with.

valdeztke

So for those using an LS3 block to get a 427 are building motors that are likely to fail (Charlie@RPM, A&A, etc)? Reason I ask, is that I'm looking at buying a car out in CA w/ a LS3 427.

Appreciate any feedback.

johnodrake

Which is why I don't have a 427ci LS3

pmj341

I have a Katech Ls2 427 sleeved and it is a great piece.
4.125 bore X 4.0 stroke, I love it!!!
no problems at all, call Jason at Katech !!!

valdeztke

Can someone expand on this a bit...I'm not quite sure I understand what this means for longevity or dependability.

QuikZilver

I looked at the different options for stroker LS3 short blocks. I decided to go with a 418 with steel top rings. I use my 08 as a DD and for drag racing. I wanted the option to add power adders (NOS, Turbo, SC, etc.) and the 427 LS3 was not recommended for FI. Texas Speed offers both the 418 LS3 and 427 LS3. The 418 I am having installed is coming from TS. Maybe give them a call as well and discuss your options.

valdeztke

Anyone? Redline? ECS?

Sparo2

Doesn't the strength and dependability of the block also depend on how it was resleeved? ....Using dry or wet sleeves.

I've heard they have even bigger than 4.125 bores for the LS2/LS3 blocks and turn out to be much stronger than the LS7 block itself.

Correct me if i'm wrong though.