*****/cons of either power plant? Trying to find the best combo for a 427. Any problems with the mains on the LS7? Dry v. wet sump? Some of you guys have alot more brain power than I have with these engines, educate me on what you think. Any opinion would help.

 

I am building a 427 LS7. I did a lot of research and found alot of companies would not touch a resleeved block. If you are going FI I would say the Darton sleeves in the LS2 would be alot stronger but for a NA application the LS7 will be plenty.

 

Katech does high quality work on sleeving blocks. I consider their work to be art.

 

It depends on what you want and the costs. The LS7 was more than the sleeved LS2 and had no boring options. There have been talks of lower pricing, but I have yet to see it. The resleeved LS2, done by one of 2 shops, (Katech or R.E.D), should be the best bet IMO. Using the LS2 case with the Darton LS7 sleeves allows for alot more bore options, thus more cubes for less money. You also get longer sleeves, which allows for the use of longer strokes, which once again equals more cubes. The only advantage to the LS7 is billet mains, and I see no use for them unless your going for 1000 hp. In a cubic inch battle, the sleeved case is far superior to the LS7.

 

Just ordered my 427 LS7 from LME and the price of the block went down something like 700 bucks!

It really did go down because I waited until they had the new pricing before I ordered.

I'm going NA so I wasn't concerned about any strength issues, and now that the LS7 block is cheaper than a sleeved block, it was a no brainer for me.

Even Brian at LME said he would do the LS7 block over the LS2 sleeved for various reasons including the main caps are better. You won't go wrong either way but the LS7 is now damn affordable.

Matt

 

+




Brian is the man. I have dealt with him in the past and I would put LME up against Katech any day. If Brian recommends the LS7 over the resleeved LS2 I would not question his opinion the guy knows what he is doing. Good luck with your build. I think you will be very happy you went with LME.

 

I talked to Brian at length about what they do to their LS7, I liked what I heard. Since this is for a 69 I'm trying to determine the oil issues with the conversion/swap.

 

how bout a resleeved LS1? is there really any advantage of an LS2 over it?

 

Who the hell's LME??


I wonder what the weight difference between the two blocks is? One being the LS7 block and the other being a sleeved LS2 done by some of the two shops just mentioned.

 

The sleeves in the LS7 are not as strong as the aftermarket ductile iron sleeves and the ones on the end cylinders crack on power adder cars usually or eventually where they have the gap between the block and the sleeve. I do think the LS7 is great for a more normal or NA only buildup for sure. It is a very nice block.

 

Katech and LME aren't even near the same level. You talking about a fully staffed engineering, product development, C5R race team vs. a engine building shop in Houston. I'm sure LME is great with there engine building, but they can't even begin to compete with Katech. Just 2 diffrent levels there. Money being no object, between the 2, I'd have to let Katech build mine.

Well, it's 2 diffrent sleeves. The LS1 uses the MID block, which is great, but more expensive. The LS2 block is dry sleeved. Dry sleeving a LS1 dosen't allow a safe overbore because of the the placement of the water jackets in the LS1 block. The LS2 block is solid inbetween the cylinders which allowed for a thicker sleeve and more support thus allowing more safe bore and a stronger block. The MID wet sleeve LS1 would be the strongest of any of the blocks talked about due to the fact that it removes all the material between the LS1 cylinders and uses siamesed sleeves to replace that area. At this time, the LS1 MID and the LS2 dry allow the same safe over bore, but the LS1 is going to be stronger for the power adder guys.

 

Yeah I've heard good things about LME, but Katech is just in a completely different league.

 

I thought RED was doing LS2 wet sleeves now also ??? that is what I was referring too. I'm wondering if there is any advantage of an ls2 MID over an LS1 MID. I'm doubt it strength wise, but anything else?

also, an dry lined LS2 with an LS7 sleeve, will only go to 4.190, with an ls2 sleeve it will go to 4.155, an ls1 MID will go to 4.200. as far as I know anyway...

 

Yes, I am now doing MID installs on LS2 blocks. Attached is a photo of the first block I did being machined. Darton will soon have MID sleeves for the LS7 blocks as well.

I consider the LS1 with MID sleeves the strongest of the sleeved blocks. Second would be the LS2 with MID until the MID sleeves become available for the LS7.

The LS7 is a nice piece. I have a couple left here. I'm going to save one for a build for myself.

I resleeve quite a few LS7 blocks with Darton dry liners. Almost as many as the LS2. The advantage of sleeving the LS7 is the ability to go larger bore and much greater strength of the Darton ductile iron material. The stock factory sleeves have a tendency to crack if you really lean on the engine, nitrous or even normally aspirated. Erik is sending one in to resleeve. One of my CNC machine customers called me last week telling me of his customer's NA block that cracked.

In any event, if the stock sleeves crack, the LS7 blocks can be repaired.

Steve

 

I wasn't sure if the MID was avalible in 4.200" yet, so I kept my size on the safe side. I know there was talk about it, but wasn't sure if it ever happened. Either way, it looks like Steve just cleared it up.

 

I have done several LS1 MID's to 4.185" bore. The limiting factor on going to 4.200" was the head gasket. There was a tolerance problem with some gaskets overlapping the bores if you went much bigger than 4.185".

Cometic is correcting this problem with a 4.210" bore gasket made to closer tolerances. That is as big as can be made by them by the way.

Steve

 

The stock factory sleeves have a tendency to crack if you really lean on the engine, nitrous or even normally aspirated
Steve, I'm going to jump in and ask how much you mean by "lean on it" with a NA motor. I'm only looking for an increase of aprox. 100 extra ponies with a stock engine.

 

he's talking about a LOT more than that. probably 800+

 

If the engine detonates the stock sleeves will most likely crack. Too much compression, too lean, too hot a plug, bad tuning (too much ignition advance).

This cracking due to detonation is typical of any late engine be it LS, Honda, Nissan, etc. I just repaired a three cylinder Rotax See Doo racing engine with a cracked liner due to poor tuning.

Keep it out of detonation and you should be fine with an an extra hundred horsepower build.

Steve

 

Here is something related. C5R blocks vs sleeved blocks

https://ls1tech.com/forums/generation-iii-internal-engine/310618-c5r-block-info-vs-sleeved-blocks.html