Hello,

I would like to build a 416ci LS3 stroker with a 11.5:1 compression, 6700rpm limit and I am contemplating if it is worth to invest ~$3000 for ported heads?

What kind of horsepower gain will be achieved due to the ported heads?

The engine will not be boosted.

Can you furthermore recommend a hydraulic roller camshaft which will not be significantly harder on my valvetrain and without a loss in midrange compared to my old cam?

I would like to keep using the gm performance hydraulic lifters and stock rocker arms with a trunion upgrade but I don't want to invest several thousand to upgrade my valvetrain (shaft mounted rockers, solid mechanical roller lifters etc.) to cope with a wild cam.

The engine is used in a drift car and hence the engine often stays at the rev limiter and is experiencing wild rpm fluctuations, hence it is essential to stick with a mild cam to preserve the valvetrain.

As it is a pure track car I do not care about low rpm driveability or a smooth idle.

Old Cam: BTR LXL lobe 226/234 .605/.612, @ .050", 113+3 LSA

What do you think about these cams:

BTR 400NA V2 236/25X, .636"/.636", 114 LSA

Comp 239/255, .624"/.624", 114 LSA

 

Changing the cam isnt going to matter much if youre still using stock heads. You wont see gains worth the effort.

Yes the LS3 castings are probably one of the best factory options, but they will still limit performance. Its basically going to be trying to drink a pitcher of beer through a coffee stir straw. A 400+ displacement needs to be fed.

 

Gumpx, check out this thread. It’s a 403” I built last year. In a NA application, cylinder heads are everything. A 416” would have only helped this combo. I’ll tell you that the 3.9” stroke crank I used will help you with piston life and ring seal. In a track build application, reliability is top of the list. I’m not suggesting that you spend the coin on the heads I used, but only using this build that did right at 600 wheel on a DynoJet in hot humid weather, to illustrate to you what heads will do to a NA build. Also precision machine work is mandatory, as is the tune. Don’t cut corners…you cannot afford to do that. Here’s a link…https://ls1tech.com/forums/generatio...-n-buildo.html

 

How much power do you realistically need?

I think stock ls3 might take you as far as you need to go.

Which intake manifold? I’d prioritize torque production in your induction and cam choices. When you’re at redline in drifting you’re already spinning the tires.

 

We built a 416 11:1 on 91 octane with stock LS3 heads/intake/injectors and a BTR Stage3 cam I believe. It had mid length headers, crush bent dual 2.5 exhaust, alum flywheel/RXT, T56, 335/30/18's out back on a 12 bolt. It made 560rwhp which was super impressive. Customer later the ported heads, did the rod mod to the intake, got a custom cam, 3" mandrel bent dual exhaust and it made around 595rwhp. The intake was probably holding him back but that is impressive.

I like BTR parts as they test everything on their Spintron machine.

Making power N/A is simply how much do you want to spend and to reach the next "level" you have to pay to play. If you are going to do it... port the heads from the beginning. You can change the intake easily later if needed. Run as much compression as your fuel allows. 3% increase in power for every full compression point you go up. 500rwhp at 11:1 would be 515 at 12:1 etc approx. Porting production LS3 heads should be around $1K or so.... depends what else they need. True LS3 hollow valves will allow you to spin it a lot higher than heavier L92 valves etc.

 

I am just drifting for fun, no competitions, hence there is no power level target but it would be nice to be able to better keep up with the other drivers who have boosted 2JZ's with around 700-800hp at the flywheel.

My LS3 made around 485hp at the wheels (conservative dyno) until recently and I am using individual throttle bodies.

 

I'd just run stock unported heads tbh. 25whp is not going to make or break you. $3k isn't worth it imo. The cadillac lifters are a great option that don't break the bank. Stock rockers and trunnion upgrade will be perfect. Get good valves, you don't want to drop one. I still think your midrange is going to be most critical for your usage, and ported heads show the biggest gains the higher you rev it. Big fan of the extra cubes, and I think that was money well spent.

If you're just drifting for fun I imagine people aren't throwing as much grip as possible at the rear and airing tires down to run crazy fast. The boosted cars with 7-800 hp probably just light the tires off when the boost comes in. If you find yourself getting gapped you can throw nitrous at it and gain 150whp when needed

 

Do you mean by "cadillac lifters" the 12499225 ones? I already ordered those.

Stock rockers and trunnion upgrade is what I run for 5 seasons already and with the cam I use I did not experienced valvetrain problems yet.

Hence I would like to stick to that and not invest in a more expensive valvetrain.

Which valves can you recommend? The supertech ones? Why not reusing the stock LS3 ones? The intake ones are sodium filled and pretty light.

I never had to complain about the midrange the LS3 provided during drifting, never clutch kicked the LS3, however more topend would be very nice to have but having to pay 3k for 25whp more top end is a bad price-performance ratio indeed.

You are right about the folks I usually drift with, they run conservative grip levels in the rear as do I.

I would like to avoid using NOS otherwise I wouldn't be in the position anymore to joke about the 2JZ drivers having to heavily rely on it.

Are you drifting an S13 with a stroked LS3?

When I was young and stupid I used to have several S13 and S14 but then I came to my senses and switched to an old BMW chassis which I can find at every junkyard for cheap.

My decision was also confirmed once I saw what happened to an S14 from another drifter which crashed into an E46, the S14 looked like a Banana whereas the E46 looked way better after the crash.

The S14 driver had to be helicoptered out (he recovered) whereas the E46 driver had no health issues.

 

88958689 Chevrolet Performance Cadillac Racing LS Lifter Set - 16 High Performance Lifters

These are the lifters I meant. You're fine with the ones you ordered too, but as far as I know it is just a stock lifter.

The stock ls3 hollow stem valves should work well with conservative rpm and valvespring package. If you look at aftermarket or ported head offerings most are using solid valves as their advertised price. L92 valves or solid stainless aftermarket.

Haha no S13 for me, but I can see it in my name lol. Just an old nickname from a couple decades ago and LS1Tech doesn't allow name changes. I do have an LS7 FD street car that I track though. Had a stroked LS2 in it before with stock ls3 heads and a mild cam, made low 500's whp. Stock LS7 heads with a mild cam dyno'd 595whp.

If I crash that FD I'll probably just be dead lol. I say that and people don't like to hear it, but they're tin cans. I've seen some mild wrecks buckle the entire chassis. I don't want to hack the car up and make it a race car, but I do think more about safety as I get older. I'm just doing HPDE's, but things happen fast.

 

The lifters I ordered are not the stock ones, they are GM Performance ones and are regarded as an upgrade over the stock ones.

Not sure if the ones you suggest are an upgrade over the GM Performance ones?

The FD3 is a fantastic looking car but the wheelbase is too short for drifting in my opinion.

I can confirm that the chassis is super tiny, especially by todays standards, I once managed to cram my frame into one and it felt claustrophobic.

You achieved a respectable output with your LS7 with minimal mods but these engines are super rare here and not sure about reliability, you are not supposed to bore them and I read about them dropping valves.

A guy I know is selling a new crate LSX-R, ~760hp out of the box but comes with a 50kg weight penalty, maybe I should go for that instead and sell the LS3 once it has been rebuild?

I could buy the LSX-R for a fair price (not overpriced but also not cheap), but might be overkill for a non-competition/non-pro driftcar and would need to run on E85 due to the 13:1 compression ratio and E85 is hard to get here.

Another option would be a hellcat engine which I could get locally as well for a fair price and for less than the LSX-R but I would have to fabricate new engine mounts, headers and properly wire it up to my aftermarket ECU.