Generation IV Internal Engine - Piston suggestions for my new 6.0L LFA

Hey guys,

Tonight I'm picking up a 6.0L LFA (http://en.wikipedia.org/wiki/GM_Vortec_engine#LFA) engine with 92k on it. It had valvetrain noise. Heres what I have planned for it right now.



Stock crank
New crank/rod/cam bearings
ARP bolts
L92 heads w/GM gaskets
LS3 intake/TB
LS7 lifters
Ed Curtis custom cam & pushrods
Comp Trunion'd stock rockers
LS3 oil pump
F-body oil pan
LS3 front cover & valley cover
3 bolt timing chain

This is going into my '95 Mustang. My goal is 500rwhp on a budget. I know that is going to be tough, but if it only makes 460+ I won't cry about it. I know I could get to 500 with a stroker kit and sick heads, but don't got the dough for it now.

Originally I was under the assumption that this motor was lower miles and I was just going to re-ring the stock 10.7:1 pistons. I'm not a fan of GM pistons or rings, but it suits the budget. Now finding out that there is 92k miles on the motor, I'm telling myself I better do pistons and rings. Question is what do I go with? This is going to be a pump gas street car, road raced and/or drag raced handful of times a year. I'd like to be around 11.0:1 CR. Can I clean up the cylinders and stick with a 4.000" piston or do I need to go larger?

I found this deal on ebay from SLP. Although its more than I want to spend, its like buying a set of pistons/rings and getting the rods for $150 more. I wasn't planning on doing rods, but for the deal....

http://www.ebay.com/itm/220964653627?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_3492wt_1139

What are your suggestions for pistons for my application? I have been looking for pistons for an LS2 application, seeing as this is a 6.0L aluminum block.

Thanks for your help!

I've been searching for about a day for piston options and wasn't happy with my findings so I made this post. Ironically, I just found these:

http://www.texas-speed.com/p-1106-mahle-ls126-4cc-flat-top-forged-piston-set-for-3622-stroke-stock-6098-rod.aspx

These are nice because I can clean up the bores to 4.005" or 4.010" whereas all the other pistons I was finding were either 4.000" or 4.030". I'm finding that these pistons would put me around 10.5:1, so it looks like the heads need to be milled to get closer to 11.0:1, huh?

Is there a benefit of going with a 6.125" rod? Seems like your piston options get a lot better when you have one.

You will not be able to run them pistons with ls3 style heads. They do not have the correct valve reliefs.

I believe diamond makes a set of Ls2 pistons in a 4.005 bore with ls3 valve reliefs.

I just found those Diamond pistons you were talking about, #11541. The problem I may run into is last night I picked up the engine and tore it down to find scoring in cylinder #1. I doubt a 0.005 overbore would clean this up:

http://sphotos-a.xx.fbcdn.net/hphotos-ash4/283634_10150941706994786_944520021_n.jpg

I was thinking I'd need at least a 4.010" piston.

I think the most cost-effective route for me to go (providing that a 0.010" overbore will clean up that cylinder) is to buy the Mahle pistons and fly cut them for the L92 valves.

Hours of more research later.....

I'm going to go with these Wiseco Pro Tru pistons:

http://texas-speed.com/images/product/large/771_1_.png

http://texas-speed.com/p-771-wiseco-pro-tru-4cc-dome-piston-set-for-3622-stroke.aspx

The Wiseco's seem like the better buy because they are 2618 forgings instead of 4032 forgings like the Mahle's are. The Wiseco's also have deeper valve pockets to clear the LS3/L92 valves, whereas the Mahles would probably need to be flycut. The Wiseco's also advertise a 11.0-11.2:1 CR (65cc head) where the Mahle's advertise 10.3-10.4:1 (66cc head).

The only con to using the Wiseco pistons is for my application I can only get 4.000", 4.005", or 4.030". So, if a 0.005" overbore doesn't clean up the cylinders (which I'm sure it won't) I'll be going 0.30" over on an aluminum 6.0L block. From what I gather, this is the max bore for this factory sleeve. If any problems were to occur down the road and the bore got damaged, I would either need to dry sleeve this block, or find another block all together. Given the mild nature of this build, no N20 or boost, I think I'll be fine.

Using this Wiseco piston in a 4.030" bore and a cometic 0.051" head gasket, it sure would be nice to have an idea of what my static CR would be on a un-milled L92 head. Any ideas?


Trying to remember if ls1tech.com is a still a forum or has it turned into a blog site? sure seems like a blog to me.... :nono: