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Hi everyone I am new here. My name is Jay an I have some questions. I bought a block off of a friend of mine and I am looking for some direction on what to do here. I am pretty mechanically inclined however this is going to be my very first engine build ever from ground zero.
Like I said I bought a block off of a friend of mine. It is a 4.8/5.3 Gen III LS Iron Block manufactured May13th 2004 from what I can gather from the codes it.
I'll post up some pictures at the end of the thread here. I currently have a Y87 Performance package V6 Firebird that I am turning into a WS6, I bought it earlier this year and it's my project car. Mainly because I have always wanted a WS6 and can't seem to find them around here. I'll post some pictures up of that on here too at the end.
With that being said, back to the engine. I want to bore it out to a 5.7L However like I said this is my first engine build. My question is, what size do I bore it out to? The machine shops I have talked to around here seem to think that it can't be bored out to a 5.7 because none of them have ever done it. They are asking if it just gets bored out 10-20 thousandths with a different crank to make up the difference in the cubic inches or take it out the full 220 thousandths to a 3.905 bore.
That is why I am turning to this forum and looking for some expert/seasoned advice. I originally thought I might want to do a 383 stroker motor but when I seen the prices of such I think that's going to be pretty expensive and I might just build a normal 5.7. The issue lies with this block I bought, it has a few scoring marks on the cylinder wall of number 7.
If I absolutely have to keep it a 5.3 how much should it be bored out to in order to get rid of the scoring on cylinder 7 and to also keep it a 5.3 and what would that bore size and pistons be? I can feel the marks ever so slightly with my finger and i can catch them with my fingernail ever so slightly, however the person I bought it from said it ran great and had no issues with oil pressure.
So a few different opportunities with this block but my main goal is to make it a 5.7 most likely without doing a 383 stroker. I feel Id be happy with a normal 5.7. coming from a V6.
Thanks for giving my thread a look and I look forward to becoming part of the community here. Thank you again!
Before and after shots of the Firebird from when I bought it on day one in February this year to how it looks now at the end of October.
Engine Block
Scoring on cylinder 7
Side of block
Top of block
4.8/5.3
Date code May 13th 2004
Last edited by blackdragonws6; Oct 26, 2016 at 01:36 AM.
Boring it to a 5.7 is not an issue. I would suggest finding a machine shop that is familiar with LS engines. Hard to say what those scratches would need to clean up if you stayed in the 5.3 range.
When you have full control over how much air the engine breathes, increasing displacement has severely diminishing returns. The money spend doing so has even greater diminishing returns. You're likely going to trash your block and rotating assembly at some point and make less HP than the stock shortblock 4.8 guys are making.
basically, use forced induction with a stock engine to avoid opening an engine. saves you time, headache, and of course $$ on expensive parts that get "trashed". Funny how when I came to this forum people laughed and called me names for having this point of view.
SVSlow, I think I have found a good shop, they explained that cleaning boring, honing, new galley plugs, new cam bearings, testing and checking the block was just a little under $500 out the door, I feel like this is a pretty good price. I found out some more info on the block and found out it is a LM7 iron block when I checked the codes on the side of it. My question now is, do I do a bore of 3.89 or take it out to the 3.905? An if I go to a 3.905 is that safe?
...if it was my project OP, I would use the funds dedicated for a rebuild to instead purchase an LQ4\4L80E combo for your swap. That takes care of your drive train deficiencies and bolsters you for future upgrades.
SVSlow, I think I have found a good shop, they explained that cleaning boring, honing, new galley plugs, new cam bearings, testing and checking the block was just a little under $500 out the door, I feel like this is a pretty good price. I found out some more info on the block and found out it is a LM7 iron block when I checked the codes on the side of it. My question now is, do I do a bore of 3.89 or take it out to the 3.905? An if I go to a 3.905 is that safe?
It depends on what you want to spend on pistons. If you know of a good set, or are able to find a good set of factory ls1 pistons, then I would mic them and bore appropriately. The cheapest set of aftermarket pistons you will find will be about 750 bucks for pistons and rings. Always remember, the larger bore you go, the less cylinder wall you have, the less safe it is to make big power.
What power level are you trying to reach? If you're shooting for 400-450 naturally aspirated, that is VERY doable on the 5.3.
If it were me, i'd see if those scratches could be honed out and keep factory pistons with new rings, then spend the left-over cash you would've spent on pistons and spend it on a set of 799 heads and a good camshaft.
I have read many people recommend finding a stock LS1 rotating assembly and making your
5.3 a 5.7.
Just take those pistons to the machinest and have them bore to fit the pistons. Iron LS1
if the car is a daily, if you actually want to drive the car, here is some "BAD" advice
basically, use forced induction with a stock engine to avoid opening an engine. saves you time, headache, and of course $$ on expensive parts that get "trashed". Funny how when I came to this forum people laughed and called me names for having this point of view.
Nope you're still giving bad advice, Did you not notice he's starting with a bare block? So how is he going to avoid opening an engine in this case?
You usually want to bore the block to about .005" less than the final bore diameter. That .005" will be taken out with honing.
If you're not building anything too wild, just use a stock ls1 rotating assembly. The machinists can measure the pistons and decided what to bore and hone the block to. Honing should be done with a torque plate, and if the machine shop is not very familiar with LS1 engines, then they may not have an LS torque plate. In that case, I'd look elsewhere.
I see my fan club still helping me create and nurture my infamy. thanks for the support, I look forward to additional sigs in the near future spreading my name.
It doesn't stop "him" and others (my post is always directed towards the tens or twenty of readers, not necessarily the op) from using stock engines, or buying spare stock engines. Since when does owning a bare block, or one hundred bare blocks, stop someone from buying a spare, unopened junkyard engine in good shape for various reasons? You act like just because they own a hundred bare blocks they can't buy a single or multiple next used engines. Stop thinking like you are in a tunnel, open your minds. Owning more engines is a good thing. Having spares, also a good thing.
Start using yours! He asked for rotating assembly advice and you tell him to use forced induction so he doesn't have to open up his engine...that happens to be a bare block lol. Yep that great advice lol
You still have no business giving a single person advice let alone the next " tens or twenty of readers"
I'll make a deal with you, Stop giving advice and I'll stop correcting you and the rest of your correction fan club may also.
Last edited by LLLosingit; Nov 15, 2016 at 02:24 PM.
Start using yours! He asked for rotating assembly advice and you tell him to use forced induction so he doesn't have to open up his engine...that happens to be a bare block lol. Yep that great advice lol
You still have no business giving a single person advice let alone the next " tens or twenty of readers"
I'll make a deal with you, Stop giving advice and I'll stop correcting you and the rest of your correction fan club may also.
Just because somebody owns 100000 bare blocks doesn't mean that they can't install a used engine from a junkyard for the time being, or even change their mind about building it. This way they can drive the car while they build their engine. Its good advice if you want to drive the car right away. I prefer to build a car in 3 days, not 3 months or 3 years. The engine you install today is a "test engine" and gets things going while you build the "actual engine", if you actually enjoy driving the vehicle this is the ideal route.
When you have full control over how much air the engine breathes, increasing displacement has severely diminishing returns. The money spend doing so has even greater diminishing returns. You're likely going to trash your block and rotating assembly at some point and make less HP than the stock shortblock 4.8 guys are making.
Notice the emphasis on the stock shortblock, as a reliable option over building an engine. Building an engine is still a viable option and has its merit; however, it might take months or years to complete. By using a stock engine, or test chassis, (same principle) you can have a reliable "test" vehicle/engine to drive in the mean time (i.e. having fun today), and sometimes the test engine lasts longer than the built engine.
What the hell is wrong with you Kingtalon? He asked a rather simple question and your answer has nothing to do with it, He didn't ask what the weather was going to be tomorrow either but in your mind you'll probably feel the need to advise him what to wear!
To the OP sorry about mucking up your post with this nonsense, Maybe a moderator can delete all this crap.
Hi guys, sorry for my delay on my reply. I'm working on the car in stages. Stage 1 is converting the body style to the WS6 style and stage 2 is doing suspension brakes etc and stage 3 will be the engine an finally stage 4 will be the interior.
I'll post some pictures of some recent updates. However I appreciate all the engine advice. I'm not going to be racing or doing anything crazy like that. I don't want to go turbo or even supercharger or what have you. I am going to be satisfied with something close to the stock power of a 5.7 Maybe a little more power if I can do so with other internal engine components but Im not interested in the sound of a blow off valve on a domestic, I guess its just not my thing.
Also super charger would be way out of my budget. If I did anything it might be a little nitrous but even then I dont think I would do nitrous so I am just looking for a clean build to something a little better than stock. I'll be honest this is my first time starting from a block on up I have never worked on anything this deep before I am looking for a good foundation for a start and some reputable advice on what to start with.
With that said, here are the new updates on the car. (The Leather bra is just for some added protection for winter. It will come off when I get the car out for the season.)
Took off the old 16 inch chrome rims, replaced the rims with C4 ZR1 Corvette rims 17 inch 9.5's went with a bigger tire. Yokohama S. Drive 175 40 R17
New Front Plate Cover. - One didn't come with the car when I bought it so I ordered a new one.
New badges and emblems all the way around, took off the old firebird badges and put on Trans-am badges as well as the back panel firebird logo as well. Added a little extra "Last of the breed badge." It's winter here so I have her all covered up till spring.
Hey guys, I wanted to give you an update on the engine build for my V6 Firebird. Here is a picture of the new engine, almost ready to install. I have been working on it through the winter
since November hoping to have it done in a month or so.
Engine Build 
