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I’m looking to do my first full engine build, and I could use some help. This will likely be a long term labor of love, as it will be a learning experience for me. I’ve done little bits of the process here and there, but have never taken a bare block and turned it into a bespoke working engine. With that, I’m not necessarily looking for top shelf parts, as I don’t want to be out $20,000 should I do something wrong. My ultimate goal is a 600 rwhp NA 24x aluminum engine for my M6 02 WS6. My car is heavy, very likely north of 3800lbs with me in it, so an aluminum block is a must. See some of my various threads to understand why. I probably added 100lbs in just my audio install! I want to be able to road race it a bit, while also pulling off 125-127 mph trap speeds in the 1320. Something that is capable of 10 second times near a 130 trap speed if I put the car on a diet, bolted on some good tires, and learned how to drive.
To start, I need a block. I’d love to know what everyone’s opinion on the best one for the money is. I want something that I can order finished, that is ready to accept bearings and the rotating assembly, but isn’t crazy expensive like an LS7, LSR, RHS, etc.
The second thing is a balanced rotating assembly. What have some of you used successfully out there? This is an NA build, so I would like to keep the rods and pistons light but strong.
Thanks in advance for your thoughts and experiences. This should be a fun build, and I’ll be sure to document the process here.
Last edited by Tang2; Nov 30, 2025 at 09:52 AM.
Reason: Details
Step 1 - Get an LS7 engine
Step 2 - DONE! Why reinvent the wheel??
Haha! That’s where I started, but they’re hard to find in good condition and/or for a decent price, especially for just a short block. I may have missed the boat on that one. Plus, I’m kinda looking forward to building something of my own.
LS7 sleeves are thin. If you want a 427, best to get a resleeved 048 5.3 aluminum block and aftermarket LS7 heads cause heads have poor guides. Do it once best and be pretty much done if budget isn't much of a factor.
If you just want a 400+, go LS3 block with 416 stroker kit and LS3 heads. Budget with later probably wanting and going with above 427.
If you want a great performing engine that's real reliable, makes 500whp+, and is reasonably fuel efficient, call Tony Mamo. You'll never be sorry you did. I think the post suggesting sleeving a 5.3 block is spot on. Have Steve@R.E D. sleeve it, buy your heads and cam from Tony, and you'll be set.....
Start with a good foundation for thr 400ci build. If it has to be aluminum then a 6.2 block would be the cheaper route over a resleeved 5.3 aluminum block, however the resleeved block by R.E.D. would be a solid foundation.
BTW my 01 SS has all of the creature comforts and a race weight of 3,840. That's an iron block build with tubular suspension and aluminum wheels as my weight reduction. Had I kept the aluminum driveshaft and the stock 10 bolt I would have came in even lighter and another thing..600 rwhp naturally aspirated is not a cheap build.
Thanks, everyone, I appreciate the input so far. No doubt 600 rwhp isn’t a cheap build, but perhaps doing a 427-440 based on a RED resleeved block may be the play. Doing a 416 would be the most cost effective bottom end, but probably more expensive to get north of 550whp with that. I’ll look more into these options.
I happen to have an RED sleeved block on the shelf and custom built Wiseco’s to go with it. Send me a PM if your interested…
Funny, I read a lot of your posts as I was researching this. If I didn’t want to build one myself you and I may have been talking about building one instead of just parts. Definitely appreciate the offer, I’ll PM for more details on what you have.
I had RED bore and sleeve a LS2 block.
Stroked it to 427 cubes with a Manely 24 tooth crank stroker kit.
With a built 4l60E auto It did 495 rwhp on the chassis dyno.
Small to medium size cam. 225I/230E .610 114 cl.
Stock LS3 heads.
Drove like a stocker until to punched it.
For 600 whp, you will need all the displacement you can get. Start with a 6.2L block. You can either order a complete rotating assembly, or piece one together yourself. It helps to have a good machine shop close enough to help with machine work.
To achieve your goal, you will need aftermarket heads, and probably intake as well. Having a manual transmission makes it easier, but 600 at the wheel is a lot for an NA build. The small bore LS7 heads would make it easier though. It just depends on how much you are willing to spend.
To achieve your goal, you will need aftermarket heads, and probably intake as well. Having a manual transmission makes it easier, but 600 at the wheel is a lot for an NA build. The small bore LS7 heads would make it easier though. It just depends on how much you are willing to spend.
Not to mention an intake that will flow that and fit under a stock cowl! There is a lot of cost to one that fits that build!
For 600 whp, you will need all the displacement you can get. Start with a 6.2L block. You can either order a complete rotating assembly, or piece one together yourself. It helps to have a good machine shop close enough to help with machine work.
To achieve your goal, you will need aftermarket heads, and probably intake as well. Having a manual transmission makes it easier, but 600 at the wheel is a lot for an NA build. The small bore LS7 heads would make it easier though. It just depends on how much you are willing to spend.
THIS ^^^^
Surprised no one else has sobered up the OP yet
600 RWHP N/A will never be relatively affordable nor is it easy to accomplish. It takes a solid designed combination with good parts to get there. If it was relatively affordable and somewhat easy there would be alot more people driving 600 RWHP vehicles.
If you crack 600 wheel NA in an LS pump gas street engine your probably in the top 5% of most of the N/A builds out there....open to debate but I bet that's a pretty close guess if you looking at ALL the potential builds that people embark on
To truly get there you will need cubes and likely more expensive LS7 heads if you want anything remotely streetable and that complete combination will cost you every bit of 20K if you build it yourself....more if you source it somewhere and have to pay for labor etc.
This hobby has gotten alot more expensive in the last four years unfortunately....its best to go into a new build with somewhat realistic financial expectations and somewhat realistic performance expectations.
550 is more doable but even that isn't an affordable venture....still requires a stroker engine and a good top end. Machine work is pricier also these days....it all adds up rather quickly
I would love to help you out but I felt it was important to reset your expectations a little. You won't touch anywhere near 600 wheel without spending at least 20K if your starting from scratch.
My advice is reset your expectations a little and/or your budget....hopefully there is a compromise of the two that leaves you with something you can work with
If you use an aftermarket block or original LS7 block, then yeah, it will cost close to $20k. If you start with a 6.2L block, you can build it yourself for closer to $10-12k. The 418 I just built cost me about $7k with an LS3 top end. The small bore LS7 heads/intake would have been about $4k more.
To build it that cheap, I had to find surplus parts from places like Facebook Marketplace. You can’t build it that cheap by ordering everything brand new from places like Summit or TSP.
If you really want a 600 whp N/A engine, it can be done. But as Tony said, you need to be realistic with your budget and goals.
600 RWHP N/A will never be relatively affordable nor is it easy to accomplish. It takes a solid designed combination with good parts to get there. If it was relatively affordable and somewhat easy there would be alot more people driving 600 RWHP vehicles.
If you crack 600 wheel NA in an LS pump gas street engine your probably in the top 5% of most of the N/A builds out there....open to debate but I bet that's a pretty close guess if you looking at ALL the potential builds that people embark on
To truly get there you will need cubes and likely more expensive LS7 heads if you want anything remotely streetable and that complete combination will cost you every bit of 20K if you build it yourself....more if you source it somewhere and have to pay for labor etc.
This hobby has gotten alot more expensive in the last four years unfortunately....its best to go into a new build with somewhat realistic financial expectations and somewhat realistic performance expectations.
550 is more doable but even that isn't an affordable venture....still requires a stroker engine and a good top end. Machine work is pricier also these days....it all adds up rather quickly
I would love to help you out but I felt it was important to reset your expectations a little. You won't touch anywhere near 600 wheel without spending at least 20K if your starting from scratch.
My advice is reset your expectations a little and/or your budget....hopefully there is a compromise of the two that leaves you with something you can work with
Cheers,
Tony
I appreciate the response, Tony. Definitely echos a few other discussions I’ve had recently. I’m actually chatting with Scott Cramer about potentially building a short block now. I already have a stout 346 in the car, and I don’t think it would be worth pulling for something that doesn’t make considerably more power. The cost of the parts to get there is just too much for me to risk on a first build. Unfortunate, but it is what it is.
A thought, considering you want to make at least a 100whp more than what you have now, I would look heavy at reverse engineering your build. What I mean is, like KC mentioned, the intake manifold is your choke point, no matter what heads/short block go below it. I would research heavy and decide on exactly what intake manifold will fit and make the power you want and let that decide how the rest of the motor looks. Making it bigger is easy, making it work is harder. The good news is that this has all been done before, so lots of researching will help. My .02, I would look at a Tony ported MSD LS7 intake or Performance Design LS3 intake like what Scott ran on that Vette build he recently did. You could have Tony port your LSXR cathedral intake and stay the course with that. I do think that intake will support 600whp, the key being the heads have to be enough to utilize it. For reference, I'm putting Brodix BR1's on a my 392ci shortblock. Undecided on intake, but it's going either carb style and up or a Summit MaxAir sheetmetal if I decide to go out the front. I'm shooting for similar power, but reality is LS7 architecture will make more power. For a budget build, a 6.2 block with a 3.90 crank, GPI small bore LS7 heads, Tony MSD intake will make the power you want and be affordable.
A thought, considering you want to make at least a 100whp more than what you have now, I would look heavy at reverse engineering your build. What I mean is, like KC mentioned, the intake manifold is your choke point, no matter what heads/short block go below it. I would research heavy and decide on exactly what intake manifold will fit and make the power you want and let that decide how the rest of the motor looks. Making it bigger is easy, making it work is harder. The good news is that this has all been done before, so lots of researching will help. My .02, I would look at a Tony ported MSD LS7 intake or Performance Design LS3 intake like what Scott ran on that Vette build he recently did. You could have Tony port your LSXR cathedral intake and stay the course with that. I do think that intake will support 600whp, the key being the heads have to be enough to utilize it. For reference, I'm putting Brodix BR1's on a my 392ci shortblock. Undecided on intake, but it's going either carb style and up or a Summit MaxAir sheetmetal if I decide to go out the front. I'm shooting for similar power, but reality is LS7 architecture will make more power. For a budget build, a 6.2 block with a 3.90 crank, GPI small bore LS7 heads, Tony MSD intake will make the power you want and be affordable.
Thanks, I appreciate the alternative advice. Nothing is off the table, so I’ll consider a few options with this in mind, too. 600 rwhp is not a must reach, but it would be pretty cool.
I’ve been going through a ton of build threads that have dump and/or track results. @Tuskyz28 cookbook is a great thread. Interesting to see the M6 cars above 3500lbs that reach 130mph. There are some sub-427 engines with cathedrals that do well. @Tony @ Mamo Motorsports also has some great examples of cathedral builds that should reach 550 wheel in my setup. Not sure it’d make sense to pay for a build that isn’t going to completely satisfy me, though. Especially since it’s from scratch, and the extra cost to go to the next level is relatively low from that point. I can’t imagine building a 416 only to want more in two or three years. That sounds like me, though! What a waste of $$$.
My other problem is that I really want to build this thing. I get as much satisfaction from putting stuff together as I do using them. Shoot, maybe more to be honest. That only gets amplified if the end result is also great. I have a number of decisions to make before proceeding, but I’ll keep this thread updated as I make progress.
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