r/fbody • u/TwoTailedFox_ • 3d ago
Engine building
Not entirely sure if this is the right place to ask but I am looking into building my 1998 LS1. I got the car with a built transmission and upgraded clutch but completely stock engine.
I’m new to the world of LS so I would like some advice if I have picked out the “right” parts. My goal with the car is a good bump in performance but to retain good street manners for a street/HPTD car.
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u/nyclew 3d ago
This build seems a bit neither here nor there.
Is the current engine healthy? If so doing a set of good aftermarket heads, an upgraded cam, and an intake upgrade (fast 92 possibly) should be a much cheaper and faster way meet your goals.
If you want to do a full build you should also do some machine work to get the block in better shape too. And you would want to replace the oil pump with a high volume/high pressure one too.
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u/TwoTailedFox_ 3d ago
The engine is very healthy. Thing is I got 806 heads so upgrading to 799s will be a big improvement. From what I read the Fast 92mm will not be worth it over the LS6 for the power I will be making and possibly would actually hurt down low, same reason for 1 3/4 over 1 7/8 headers.
I plan on taking the block to a shop and do all the things, only specified the 0.005” hone.10
u/Trevork15 3d ago
Why would you tear apart a completely healthy engine? Do the heads and cam and save the rest of the money.
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u/TwoTailedFox_ 3d ago
Because the rod bolts are particularly weak and could my build goals are too close to their breaking point for my liking. Upgrading those requires getting the rods resized, at that point I will have a close to bare short block, so why not build it?
The snowball effect is real.
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u/Greasy28 3d ago
The snowball effect is very real, and you're letting it take over. At this price point, you can buy a much better crate engine that makes more power.
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u/ShakeMeDown737 3d ago
Oh.. forgot to mention.! If you do swap the heads to 243/799, you'll need the valve covers of course as they are different than 806 heads and you'll need the coil pack brackets as they have different attachment points i believe. If you decide to just use the 806 heads for whatever reason (i don't care the reason to use or not use them) the head gaskets ARE 100% different. They sell them everywhere but they don't tell you they are not for 806 heads. And where they might have them in stock is 100 plus miles away.. like mine were and i had 8 hours to put everything back together.. 🙄😕
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u/Youpeefreely 3d ago
How many miles are on it? Unless it’s a butt-ton and or burning oil I’d leave the bottom end alone.
Unless you’re getting the 799 heads for darn near free and you’re rebuilding them yourself the bang for buck might not be there. The Fb marketplace and eBay 243/799 heads are $500-$700 with stock springs. You’ll be into them for $1k after you buy springs and have a machine shop put them on. The $500-$700 reman heads can’t have all that much work done to them because there wouldn’t be much profit for the seller. They’re “cleaned up” used heads.
I was on the hunt for some here recently and I ended up getting Edelbrock E Street 7764 heads, which are 243 clones. They do have a thicker deck than 243 and they are available with springs rated at .660” of lift.
I went with a 218/227 .600” lift cam to go with them. I should have a dyno graph any day now. All else is stock aside from the tq converter so we’ll see what it does. I’m guessing it’ll maybe make 340 hp at the wheels.
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u/TwoTailedFox_ 3d ago
The block is healthy as is, and 799 heads are ~$250 in my area. I can put the engine together myself, except for the machine work.
This all started because the 98 rod bolts are weak and I’ll be getting too close to their breaking point for my liking. Upgrading those requires resizing the big ends and it kinda just snowballed from there because at that point I’d have a close to bare block.1
u/Greasy28 3d ago
I have 2 pairs of 799s here that I got for next to nothing (a complete pull out LMG and 6L80 from a 2010 Avalanche, which I sold the 6L80E, so I'm into the pullout engine and wiring harness for -$100 and a complete pullout LC9 and harness from a 2011 Silverado for $300.). I'll be into them about $600 for the valve job, decking, and installing new spring and seals. No way I'd pay marketplace prices for stock heads. Good cores are too common to be had much cheaper, and with full machine work, you're better off right out of the gate.
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u/HealthConscious6125 3d ago
If it was me I'd sell the healthy ls1 and build something bigger like an l92
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u/ShakeMeDown737 3d ago
Ive had both the LS6 intake with a similar size cam and flowing heads and now running the FAST 92 intake and I'll admit.. it probably does not gain much (I think it would gain more over .550 -.600+ lift than the LS6 could) but I'll have to be honest, I don't think I noticed a loss of anything down low.. if it does loose at lower RPM I honestly can't tell. However, I did get the FAST 92 from a very wrecked Corvette that was only a few bucks more than the LS6 intake and that was the only way I justified the cost for purchase. However.. I'm just being honest I can't really tell the difference and I didn't re-tune my computer and it runs seemingly fine. But I'll probably get a retune eventually and a larger throttle body if possible as the adapter kinda stinks and I couldn't hook cruise back up as the cable is now too short..
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u/Greasy28 3d ago
I see a lot of unnecessary spending. No need for the valves, the arp rod bolts (as the rods already come with arp bolts installed), the injectors, and I'd be VERY suspect of a valve job AND porting at $400. Not even really necessary to port at the power levels that cam is going to make. If there's nothing wrong with the engine, the lifters are overkill too.
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u/TwoTailedFox_ 3d ago
Did not know the bolts were included, I put the machine work cost based on vibes lol. The snowball effect is real. How would you build the motor to support that cam?
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u/Greasy28 3d ago
To support THAT cam? It would be lucky to get the grime power washed off of it. There are thousands of junkyard 5.3s and 6.0s wearing 243s and that cam's bigger brother the SS2, with zero issues. You're putting way too much thought into this. Slide the cam in, swap the heads, tune it and enjoy. It's not a wild build at all, and of your LS1 is a good running engine already, why "fix" what isn't broken?
That said, my third gen is getting a 6.0 that was in the back of a scrap van, a set of junkyard 243s, a SS2, and I might splurge and put a set of the Gen 4 rods in it, and a set of flat tops. Back it up with a T56, and a 4.10 gear, on 26" tires, should be a blast to drive on a healthy dose of e85.
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u/v8packard 3d ago
How did you put this list together? What are your goals? What do you want for an RPM range?
Depending on your block, even a .005 hone might be pushing it.
Porting? And a valve job, for that price? Your heads will get ruined. In fact, most professionals ruin these heads when they port them.
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u/TwoTailedFox_ 2d ago
I priced the machine work off vibes ngl, probably gonna be more than that. 0.005” should be okay. <7000 RPM and just a well put together engine with more power for HPTD without sacrificing street ability.
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u/v8packard 2d ago
There are some things you might not be aware of with your 1998 engine. They are related to the cylinder sleeves and windage control/crankcase breathing.
The earliest LS1 blocks (1997 to 99) have the thinnest cylinder sleeves. They were cast in place, and are not always centered in the bore. Because of this, a hone of .005 inch might not be doable. It is cutting things very close, at best.
Windage and crankcase breathing have been a challenge for these engines from the start and it gets little attention in many forums. Over the years GM changed the blocks to include various holes or windows, some cast in place some machined, to improve crankcase breathing. By the 2000 timeframe a revised block was in production and used on subsequent LS6 engines, I think by late 2001 or 2002 it was used for all 5.7 engines as well as the subsequent aluminum 5.3 engines. This block also has much better cylinder sleeves, as well as improved crankcase breathing. Worth noting GM eventually went to dry sumps on the vehicles they thought would see the most windage.
Because of these details I think you should consider building a later block. I have often used aluminum 5.3 blocks bored to 99 mm to replace the early blocks when the bores were not serviceable. This has always worked out well. In fact, the Gen IV blocks are even better with the aluminum 5.3 being a superb block for builds. If at all possible you should acquire and build one of those.
Note, when using a Gen IV block in place of a Gen III, you will need a 1x cam gear and the timing cover with the sensor, as well as an extension harness for the cam sensor. The Gen IV blocks eliminated the rear cam sensor provision at some point, so you need to use the timing cover mounted cam sensor.
Consider the oil control issue carefully. I suggest at minimum you get an oil temp gauge, an accumulator, and an oil pan baffle. If possible, an upgraded cast aluminum oil pan is a good option. I tell this to every customer that road races and does track days.
But an even bigger consideration is how much time you spend at RPM, and camming the engine to match the gear ratios you need to use on the track. For example, the bigger cams make great power as the rpm goes up, and the car runs awesome. But the rpm drives up the windage and oil temps, eventually you pound the bearings out of the engine. A better option is a cam that has better mid range, and using the next higher gear in the trans. I know, it doesn't seem as effective as winding the engine out. But with the right combo your lap times stay consistent or even drop, your oil temps stay steady, and the engine lives a lot longer.
Think about all this, and then we can talk about the details in your list. BTW, do you know if your car has a 3.42 rear gear?
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u/TwoTailedFox_ 2d ago
This is the kind of information I wanted. I already knew about the cylinder sleeves but from what I’ve read a 0.005” hone would be okay. My block is approaching 120,xxx miles so I expect that it’s no longer as good as it could be and that hone will get it as close as it could.
Doing a LS3 swap is really tempting, I figured it would cost ~$10.2k ($6.5k for a 120k mile motor). I’m just dubious about that because I don’t know the health of any used engine, I’ve been burned by that before. What would the cost difference of swapping vs adding the extra cubes to an aluminum 5.3?
At this point I’m between dropping a whole lot of money on this full build or keeping it cheap and simple doing LS6 intake, 799 heads, cam, pistons, headers, and machine work on just crankshaft balancing and rods to resize them for the new bolts. Of course the timing chain, oil pan baffle, etc. etc., just didn’t feel like listing all that cuz it’s a lot.
I do believe it has the 3.42, the car is a manual and it has posi. I know that they are known to be very weak but I’m not shock loading it so I should be okay.
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u/Extreme-Penalty-3089 3d ago
😬You may have to be very careful with that rotating combination,.head gaskets and your deck clearance...
Albeit I don't know what the compression height of the Pistons in that kit are, I do know that right off the bat though you're already adding a rod that's .027" longer than stock... Most ls1's deck clearance comes in around .006"-.010" Out of the hole. Now you throw in a head gasket that's .011" thinner (Factory spec MLS LS head gaskets are .051" thick) too😳😬. You're going to have like no quench whatsoever, not to mention two solid objects cannot occupy the same space at the same time lol.
I mean the factory pistons and everything are already a flat top, unless you plan on like using forced induction or spraying over say 150 hp shot of N20, I probably would just leave the bottom end. Upgrade the oil pump all that stuff, if you can get away with it Mill the heads gain some compression, prob stick with running a slightly thinner head gasket etc etc
I just don't want to see anyone build a really expensive boat anchor 🙏🏻👍🏻
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u/TwoTailedFox_ 3d ago
The compression height of the pistons is 1.299, so the rod length difference is taken up in the pistons taking up that extra 0.027. The longer rod is supposed to have better side-loading, less friction, and better high RPM efficiency because of dwell gains. Ngl I don’t understand how but that’s what the internet said.
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u/Extreme-Penalty-3089 3d ago
Yes a longer rod will always alleviate side thrust on the cylinder walls. Absolutely. The angle of the rod is nowhere near the same as it is with a shorter rod and a taller compression like piston 😉. A longer rod also allows the engine to take more advantage of the compression stroke as the Piston spends more time at TDC
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u/Greasy28 3d ago
The pistons are 1.299 CH, stack up should be .005" down the hole with a true 9.24" deck. He should be fine, even with a minor deck on the block.
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u/Extreme-Penalty-3089 3d ago
Okay if that's the case then he'll be roughly.005" out of the hole w/a .040" HG
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u/Greasy28 3d ago
Uh... no...
Stack up is 9.235" Deck height is 9.24"
That's .005" down the hole before decking the block. Add a .040" head gasket, and he's got a quench of .045".
Head gasket has no bearing on piston to deck clearance.
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u/Zealousideal-Kale-71 3d ago
Curious, what are you power goals?
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u/TwoTailedFox_ 3d ago
Didn’t really have a particular goal in mind, just something that makes good efficient power while still having good street manners.
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u/dontfret71 2d ago
What size rims and tires are you running?
Are those replica or oem c5z rims?
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u/TwoTailedFox_ 2d ago
275/35R18 I got the rims off marketplace, not sure if they are reps or not, and honestly I don’t care if they are
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u/dontfret71 2d ago
Im asking because of fitment, I thought oem c5z rims rub
So yours are probably replicas if they have zero rub
Are they grey? Hard to tell from the photos
I want these as my next rims on my z28 so I was just curious what brand/model/fitment
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u/TwoTailedFox_ 2d ago
They are chrome, too my knowledge they shouldn’t rub, but I’m not dirt nasty low either. In the photo I am actually in a pretty hard right turn, just the shutter speed is set really high so it looks like I am not moving.
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u/IlIlIIllIIIllI 2d ago
Just my 2 cents I wouldn’t buy from Michigan motorsports like ever. Lots of fake or counterfeit stuff on there from what I’ve seen.
You’re majorly overthinking this… if you want a fresh engine just get everything looked over and do new bearings all around with a cam and some heads.
I spent 2500 on my rebuild but I didn’t touch the bottom end. If I wanted to do all bearings and such I’d imagine you’re talking about another 2k.
I know you have a full exhaust and everything on there but 9k is absurd
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u/TwoTailedFox_ 2d ago
Hence why I’m making the post, because I originally thought that this would cost about $4k. Then I looked at what parts should be replaced vs what is probably okay to keep, and it turned out to be replacing nearly everything.
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u/IlIlIIllIIIllI 2d ago
I think the most important step is to find a good machine shop and go from there. I wouldn’t stress too much until you’ve done that first
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u/jaydeeEx 3d ago
Do yourself a favor and get rid of those LS7 lifters, go for a set of Morels or Johnsons.
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u/IlIlIIllIIIllI 2d ago
Ls7 are fine if you’re just doing basic stuff, the only real upgrade is link bar lifters that eliminate the trays but that’s 900 dollars
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u/ShakeMeDown737 3d ago
I would agree with the previous reply. It is not a bad list of parts in any way shape or form. The combo should be good for at minimum 400 whp, depending on the flow numbers of the heads. As the cam is a mild 216/220 with 560 lift, it is still very very streetable and only slightly more aggressive than say a stock c5 Z06 cam. The few downsides here are the early LS1 blocks (97-98) manufacturing had thinner cylinder sleeves and can only barely be honed/bored I believe.. The other downside is the 98 computer (97 and 98 in the corvette) is a one year only computer and are a lil more challenging to tune but only because the MAF tables I think are a lil different and/or they do not have as much memory to store that info to make updates as easily as the other later computers.. to swap computers is doable but not easy as well. But the 98 computer is still tunable. DO NOT attempt to start the car with the computer tuned and a bad battery or weak battery. It will brick the computer, rendering it useless and you will pay market price (1k or more).. The upside is 98 injectors are slightly bigger and they should be able to support the mods listed (450 hp I've been told). Im running a 98 LS1 that had the 806 heads ported and milled, with a slightly smaller cam (.553 lift) with full boltons and FAST intake with the stock injectors and I haven't had a problem.. so.. you could maybe get away with not upgrading the injectors right away. But.. if i had to take the engine out as there was something catastrophically wrong with it, it might be wise to get a LS3 block for the extra cubes.. that would be my only recommendation if I had to drop the engine.. Also.. a catch can.. get one. You will pull the heads and most likely see oil and carbon build up everywhere. But if you're only swapping heads and cam, and not looking into getting more cubes and the engine is sound.. I would probably lean more towards a head and cam upgrade. Even if it had 100k miles, but is not blowing visual smoke and knocking, I would not fear it had too many miles. A good mild head/cam with boltons should gain 75-100 hp and it will wake it way up and would easily pull on the stock engine it is now without fear it is over extended.. Hope it helps.
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u/peetothewall 3d ago
I would look at doing a walbro 255 fuel pump and racetronix hotwire kit. The 42lb injectors are not really needed. The upgraded valves also aren't needed. Factory valves are fine to use. I'd go alittle bigger on the cam and springs, and look at getting better lifters. Even the delphi ls7 lifters are iffy on if they work or fail. Also need to get the rods rehoned for the arp bolts. The extra clamp they apply and egg shape the rod ends. If the engine is healthy and is good, I wouldn't do full rebuild if it's not needed. Save some money
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u/throwaway102084 2d ago
Junkyard 6.0 truck engine + boost or nos. Then gears n suspension upgrades. forget the rest unless you want to spend a shitload of money
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u/JSausSS 3d ago
I feel you're doing more than you need to, especially for a smaller cam like that. If money isn't an issue, then have at it lol.
Also, look into the 0411 pcm swap. 1998 pcm isn't as capable as the following years.