So its finally time for my weary old LS3 to be rebuilt. (jk, its at 80K miles and running fine).

I want to do heads, cam, piston, and rods in prep for a little boost. I'd be happy with 600 WHP so I don't have to start swapping drivetrain parts.

List:
AFR 260CC Mongoose heads
Spinmonster spec'd cam (will this be too aggressive on these heads?)
JE drop-in no balance pistons and h-beam rods.

My plan is to self-build, meaning very little machine shop work if possible. Hence, no balance pistons, new heads and cam. Before anyone suggests "just boost it" - I need to do heads (issue with my current set, possibly burnt valve seats from prior owner), and pistons (my fault, bad tune = little knock marks).

Pricing for these 3 major components will come in at around 6K~ish... and some peripherals will probably add another 1-2K head bolts (should i go stud?), pushrods (length??), lifters (OEM? or ?? ), Trunions or bearings (??)...

I'm thinking under 8K I can have an engine that would be comfortably pushing 500HP NA, with rods/piston/heads capable of 800ish.

Any suggestions? pointers for brands to go with for the unknown items? Anything bad with my plan?

Supporting mods on car:
cold air intake
kooks 1-7/8 headers
twin plate clutch to be done at the same time...
i assume i have to upgrade fuel system - injectors, fuel pump

 

For those goals you do not need pistons, rods, heads, and even a cam. I personally would do the A&A kit, cam/supporting mods, and meth and call it a day. The blower kit is around 6grand including injectors and a boost a pump. You do not NEED an aftermarket fuel pump for that power level, but for peace of mind I would say go for it even though the boost a pumps dont fail very often. You're going to spend more than 8k unless you do all the work yourself or piece used parts together.

 

I'd skip the heads. Yours can more than likely be fixed. Port them if you must, but stock LS3 heads flow more than enough for 600 rwhp with a blower. Spin's cam is a very good one, but I'd choose one more specced for the type blower you're using. If you can swing a flex fuel system, that would be a VERY nice upgrade to go along with the blower. Up the static CR to go along with the E85. Free power if you have the octane to support it. I'd just use a quality set of head bolts and skip the studs. They're easier and will save you a little money too.

 

Like everyone said, you dont "NEED" ported heads to reach your goal...

However, the bennifit of doing heads is the fact that you can make your desired HP goals with less boost... which equates to less heat, which equates to lower octane requirements, which equates to easier tuning capability, which makes for better street manors (In my opinion) This also leaves room for MORE power with less boost in the future...

But most people just leave the heads alone and increase the boost until they make the power they are wanting.

SPEED SAFE, NICK

 

Thanks slowteal - Sadly, I NEED to do piston at the minimum, due to some detonation taking off edge pieces of the piston, meaning engine will be out. Since Its already out and theres only one machine shop around that is really trustworthy, I thought a few grand of insurance of "new, better" heads would be good insurance. If I'm doing pistons, I might as well do rods at the same time, right? Then I might as well do cam, lifters, pushrods, at the same time? my OEM pump is getting the fuel smell and I need to replace it anyway. At the same time car will be down for clutch/flywheel/torque tube maintenance (80K miles, its time) so I think it might be slightly easier to approach.

I want boost eventually but I'd prefer to do it in chunks for my wallet's sake... which is why my plan is:

Internals, as needed + little upgrade (piston, rods, heads, cam, lifters, pushrods, ??am i missing anything?) - 2K + 3K + 2K ~ 7Kish
peripherals as needed/maintenance (fuel pump, injectors) - 2K?
maintenance (clutch, FW, TT bearings, guibos) - 4K? (but i consider this maintenance, not upgrade cost...)


out of that list, is there anything you can see that I am neglecting to think of?

 

Thanks - I'd love to go E85 but no one around supplies it. No one around really does head machine work and shipping it back and forth will cost 1/2 the price of AFR heads which is why I'm banking on it. If the heads are fixable or fine, I'll sell it locally OR keep it for a future build. Thanks for the idea of the blower cam. I know I want to go blower but timeline is unknown. Do you think it'd be a good idea to use Spin's spec til then, and when I'm ready with the blower, buy another cam and swap?

 

Thanks Nick - I might just order them and if the LS3 heads are fine, keep them for another build. I really should just do a leakdown and check if the valves are fine... maybe ill do that before I order the AFR set.

 

I'd find a cam I liked and stick with it unless you just enjoy working on engines. I lost the joy of tinkering with engines when my back got to the point where I couldn't lean over into an engine bay for hours on end.

If you're OK with 4 degrees of overlap, Spin's cam will do you a good job. That's more than I'd want to fool with, but folks tolerance to overlap can be O (that's me) or less and well over 10 degrees. With a blower, you don't need a 230 degree intake lobe to make completely insane power. It can help n/a for sure. I'm running a Cam Motion custom grind 226/234 115+4 in my LS3 with ported and milled stock heads and all the bolt ons. 0 overlap, perfect manners, and 500/454 at the wheels. Gets good fuel eco too.

 

Reading through your post and your reply.. Here is my take just having completed a cam upgrade. First, the stock LS3 heads are really good to a pretty high number.
Watch this if you haven't already - Because you know you have to do something with the bottom end... I would suggest looking at a 416 stroker kit or a short block.
https://www.thompsonmotorsports.net/...scription=true
A 416 with cam may not get you to your 600 wheel goal, but isn't that much more than rebuilding the stock cubic inch block. You can also run the stock heads on this setup and make alot of power. If you decide to add a Procharger/A&A later then you wont have to worry about the block or heads unless your making closer to 1000. You didn't say whether you plan to do the work yourself.. but you should also make a list of the things you don't think about like : Gaskets, Sealant, Plugs, Wires, Balancer/Pulleys, Tools, Tuning software/tune, Wide band, just to name a few.

If you have any questions let me know.

 

Thanks for the video. With everyone suggesting sticking with stock heads, maybe I will just go with a set of ported LS3 stocks since I don't need the extra PTV clearance the AFR heads are supposed to provide. It would be cheaper and easier to find a heads/cam package if i go that route too. I thought of buying a stroker, as a whole package (e.g. the texas speed 427...) but I figure the cost-performance wont be there for me since I THINK I can do it for less than half the cost (20K for the package vs 10K is my price estimate for DIY).

This car will be a daily driver when I'm done. I am worried about forgetting the little things. I have new plugs, wires, wideband, hptuners. I do need to get a new balancer, balancer bolt, and a chit ton of gasket...

 

In all honesty, much like has been said a couple times already... there are people making north of 1000HP with boost alone on factory short blocks. So you dont need a stroker at all. If your building the engine, I would just build with forged pistons and rods, gap the rings for boost and add the cam you like... when your ready for boost, it will be ready for it.

If you are just looking for 600hp and dont plan to ever go more... just a set of forged pistons with the rings gapped for boost would get you there with 10lbs boost.

there are lots of ways to skin the cat... it all depends on what your needs are and what you can afford to do and if building for future potential is a requirement.

SPEED SAFE, NICK

 

Here's another opinion on LS3 heads. No way I'm pulling them off just to upgrade them. Whether the upgrade is new aftermarket heads or ported stock heads. On the other hand, if I have to take them off (such as an engine build or lifter swap), there's no way I'm putting stock heads back on. If they have to come off, I'll do a clean up mill, valve job, and probably change the valve springs at a minimum. That's several hundred bucks in labor and machine work. It just doesn't cost much more to CNC port them at the same time. Tx Speed will do all of the above, CNC port, clean and assemble with your valve spring of choice for $800 bucks and they are local to me. That includes milling as little or as much as you want. The port work may only be worth 20 hp, but milling to increase compression ratio along with adding thinner head gaskets can up that considerably. A compression bump and getting the quench right can add power all through the curve.

 

I see, didn't realize the pistons actually had issues. If you're tearing into it I would do pistons/rings, rods, lifters, pushrods, new timing chain, new oil pump, injectors etc. For the heads I was going to mention TSP porting them would be an in the middle option between leaving stock heads and spending a few grand on really good heads. You really need to think hard about your end goals and how long it will take to get you there. If you tend to want more want more, overbuild the engine now spend a few extra grand and postpone the blower. If 600hp is fine then tread lightly on how much money you throw into the motor, because there are PLENTY of 700 wheel hp cars out there that have been getting the **** beat out of them for years on the stock motor with no issues. It's all in the tune, dont forget that most important part. Finding a tuner can be like finding a surgeon, you really don't want someone without a ton of experience messing with the computer.

 

"think hard about your end goals" Yes, Agree with this. In addition.. be honest with yourself. It is a lot more expensive to go back to change it later. At some point... Its cheaper to just buy a racecar and use it for that. Have you ever had a 800-1000HP car on the track or street to see what thats really like. It sounds like fun, but also alot more to keep up with.

That said, you have mentioned this car is gonna be a "daily driver" car. I would caution you on making north of 600-700 Horsepower on a daily driver car unless you are just good with having downtime. It WILL happen. Transmission, torque tube, rear end, clutch, etc etc are all points of failure above this power level.

I am not saying it can't be done.. and there probably several who have done it with no issues, but its not the norm.

Call a few big builders and ask them how expensive will it be to make whatever power level you want reliable. And what are the things that are known to fail.

 

Thanks all. I am pretty sure 600WHP is the most I'd want. Rethinking the plan with that in mind maybe I should be doing:

1. drop-in piston/rods, TSP ported LS3 heads, a moderate cam (maybe even smaller than the spin cam?) and prepare for a smidge of boost...
2. Drop-in piston, rods, AFR heads, spin cam, and rev it high.

since I'm looking for a DD car, maybe option 1 with a smaller cam would be best for me...

I've been keeping an eye on threads for what sort of WHP the stock drivetrain can handle for extended times and it does seem like 600 isnt an issue if you're not racing every weekend. I plan on really using it mainly as a DD with a couple pulls here and there so I think it would be fine.