I am thinking about 4.100 bore and 4.100 stroke this would be 433 cid. I am not interested in putting LS7 heads on a smaller bore. I want a larger bore and cheap price, low weight. I have one of my local machine shops looking into the max bore question.

 

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Why don't you just contact Shirl or one of the many sponsors who do engines? It's not a common thing to do, so you're not going to find many people on here who can vouch for the setup.

 

shirl is the only one I've seen that has done it.

 

I dont know who Shirl is to see what they say. My machinist is supposed to have an answer for me next week.

 

Yep, he made a bad azz 441( 4.1 x 4.1 ) using a L92 block.

Keith

 

That is what Im trying to do. I forgot to call my guy today. I will try to call tomarrow.

 

Alright I called around to some sponsors today when my guy couldnt come through. Basically they all said that you could go to 4.085 without a problem. You can go to 4.100 if you get the block sonic tested because when the block is cast around the sleeves they are sometimes not quite centered. So if you bore it way over it may be thinner on one side of the bore compared to the other. I have heard of LS7 heads being put on as little as 4.060 bore but Im sure the larger the bore the less valve shouding you will have. Right now I cant justify buying a block, having it sonic tested, and having it come back that I cant bore it to 4.100.

 

im thinking if i cant get a L92 4.100 bore with my 4.100 crank 433cid, i just might just go with 4.085 bore 429.88 (430)cid

 

I dont get the topic of debate here. 4.085 vs. 4.100 is a VERY minimal difference. Talk about shrouding, which would only be on the intake side really. You are looking at gaining .0075 of cylinder for that side. You are splitting hairs man, really. I would be more concerned about the casting flaws in that specific block that have come up. If you are dead set on getting a bigger bore than 4.085 get the LS7 block. Not that much difference in price. Also consider running the TFS 235 on the 4.060/4.080 bore, that would really shine as well.

 

We are not debating the difference between bore size. I asked the question "what is the max bore of an L92 block". I didnt get very much responce so I call all of the sponsors
on the right. None have a definate answer. Those who knew anything say you could probably go 4.085 without a strength problem. One said you could go to 4.100 with a sonic test that indicates your block had no core shift and good sleeve placement. There is a $1,000 dollar diff. between a new L92 and a new LS7 block. So there is a need for a cheap alternative. Ok we can all say " use a head designed for a 4.0 bore " but it has been proven over and over again there is no replacement for displacement. If you can get more cubes, larger bore, and use a head that has massive flow, why wouldnt you for the application said above.

 

I would not recommend a 4.100" stroke in an L92 block if you are using any nitrous whatsoever. You are stuffing a lot of stroke into a block with a 5.50" cylinder length. This can make for a "train wreck" on building a piston that will survive. Our 427 cid L92 uses a 4.080" bore and 4.100" stroke, and it will make for a nice street application. However, it is not a setup that should be built for any power-adder in my opinion. The shorter cylinder length makes the high pin placement necessary for adequate piston stability at BDC. Due to the high pin placement, the thinner .043"/.043"/3mm ring pack is required. You can end up with a CD under 1", and it all adds up for a risky setup with any power-adder whatsoever. IMO, I would build a 418 cid L92. You'll have a much larger safety margin with a setup that can take some abuse on nitrous. The added 9 cid of the 427 cid L92 vs. the 418 cid L92 is just not worth the risk if you want to run any power-adder whatsoever. The 4.10" bore can be done, but at this point we do not feel that the added potential of the additional .020" of bore is worth the added risk. We want to maintain a certain safety margin on our engines.

Trevor
Texas Speed & Performance

 

Thanks for the input. I understand what your saying and I think Ive come to think that this build is not worth it.

 

I get where you are coming from bro. All I meant was the fact that you are going a few cubes and very little cylinder clearance isnt worth testing the limits of 4.085 vs. 4.100 bore. Dont fret the cylinder head deal either. It isnt a big deal to take a head intended for 4.030-4.060 and move up the runner size, seat throat dia, and chamber width to accomodate a bigger bore if you want to go that route. I dont see why you would be turned away from doing what you are saying by anything in this thread. Just rethink alittle and move forward.

 

It can be done......i have one
https://ls1tech.com/forums/generation-iv-internal-engine/629035-433-cid-stock-sleeve-l92-engine.html

 

I'm working on building a 4.100 bore l92 setup with our PRC CNC ported LS7 heads. I'll let you guys know what kind of power it produces on the engine dyno.... We've been talking over getting the ls7 head on a l92 block for a while.