What are the best LS1 heads?

Note that I did not say "best deal", I said "best". I don't care if they're a million dollars, I want to know which is best. Assume these are going on a stock-cube NA motor running pump gas.

I'm just asking about heads. Don't let included valve gear (springs, retainers, rockers, etc) sway your decision.

Is it the AFR 225s? Trickflow 215s? Dart? I know those are good, but who is the best?

I suppose that we should define "best" as "makes the most power" for the purposes of this discussion. Assume that whatever set of heads you choose to discuss is paired with an appropriate cam.

 

the TF 215s are a nice compromise on runner size, and are look like they have fantastic flow.
but not many testimonials around to show how good they are.

there is no cut and dry answer to your question.

it will really boil down to the size cam. on a smaller cam, the 225 runner size of the AFR or Darts will probably hurt low end power. but on something in the upper 23x duration it would be fine.

 

IMO the ETP or AFRs are probably up in the "best of the best" category, but Darts are starting to get some accolades as well. I'd rather spend 1/2 the money on some nicely massaged 5.3 heads and leave that extra 10-15rwhp on the table. You could buy some nice forged pistons and a cam with the difference...

Doh! I forgot about the Trick Flows... Very good as well from what I've read.

 

I can add some more criteria if that helps. When all is said and done, I want a car with gobs of low-end torque. I'm spoiled by my father-in-law's 455 Buick, and I like to autocross occasionally, so I won't always be running WOT at high RPM like a drag car. I'd rather have 450lb-ft than 450hp if I have to pick between the two. That said, I would still like to make power up to, say, 6500rpm.

 

AFR and TF, IMO, are the better two competitors. If you want up to 6500 performance, get an aggressive cam w/ the heads. MS4 cam I believe is 3600-6400 rpm powerband.

I'd like AFR heads myself but the price buggs me. Although, I've seen some 800 someodd HP cars using stage 1 LS6 heads..

 

Search around for some dyno results. If you are Ax then you want a different combination then a drag car. Are you going to stay with the stock rear gear and the ls6 intake? Are you prepared to spend the money on injectors and fuel pump? The best heads for your needs may be alot different then someone elses.

 

I will probably go with 3.73 gears, and yes, I'll keep my LS6 intake for the time being. There's no saying I won't eventually go nuts and get a FAST intake, but the LS6 should serve my current goals well enough.

At the moment, I'm not prepared to spend money on anything. I'm just asking questions. But when it comes time to do the actual modifications, yes, I'll be buying a fuel pump, injectors, and who knows how many other supporting mods for whatever route I take.

 

The Trickflow 215cc are leading the pack in power, partly because the valve angle is at 13.5 degrees on those heads, unlike the other LS1 stuff at 15 degrees.

Other stuff like ETP and All Pro is better, but more expensive and geared more towards stroker motors, or high $$$ builds, since you'll need to revamp the valvetrain with the 11-degree ETP heads and the All Pros start at 230cc runners.

For a cheap stroker motor that makes good power, I'd just get an LS2 402 and slap on some L92 heads and a nasty cam.

Any way you slice it, the LS6 intake is going to restrict you about 20 horsepower over the FAST 90/90.

 

I was under the impression that going to the FAST below a certain power level (~500bhp) would cost you in low- and midrange torque. Not true?

For my purposes, I'd rather lose 20 peak horsepower and keep it in the midrange.

 

took some info off of an article from TPIS about some dyno testing that they did with various intakes.

it was on stock cubed LS6 with a 236/241 .602/.565" 113 cam....on an engine dyno


with a stock LS1 intake:

2000rpm - 124hp/326#
3000rpm - 208hp/364#
4000rpm - 304hp/399#

peak:
488hp @ 7000rpm
432# @ 5200rpm

LS6 intake:

2000rpm - 126/322
3000rpm - 209/366
4000rpm - 307/402

peak:
498hp @ 5400rpm
446# @ 6800rpm

FAST intake w/ 90mm TB:

2000rpm - 125/328
3000rpm - 209/366
4000rpm - 308/405

peak:
515hp @ 6800rpm
447# @ 5400


granted this is on a pretty stout engine combo, but it shows you that all three intakes have nearly identical power levels below 4000rpm, with only a 1-1.5% variation from the LS1 to the FAST intake on both hp and torque.

and even the peak torque is nearly identical between the LS6 and the FAST, even occuring at the same rpm.

but the 17hp gained in the upper rpm with the FAST intake is clear.


HOWEVER...something also shown in the data was that you truely had to spin the motor to 7000rpm (or more) to really take advantage of the FAST intake.

at a more reasonable rpm limit of 6600, where many of us with bigger cams tend to limit out reving for fear of breaking things the data is as follows.

LS1 - 487hp/387#
LS6 - 497hp/395#
FAST - 503hp/401#

so unless you rebuild the bottom end to handle extreme rpms....you won't be leaving as much on the table as you may think.


so depending on your route....the $1500 spent on a FAST intake and TB setup, would be better put towards a GOOD set of heads, compared to some budget ported pieces.

granted this was all data from a single company, take it as you will...

 

Good read, Matt. Thanks!

 

It came from TPIS during one of their articles "about their new intake manifold".

It's not a good read at all.

The FAST 90/90 setup has been proven TIME and TIME again on the LSx cars.

I'd stick with that and not read into it too much.

 

agreed ...and the article does show taht the FAST is a superior intake.

but not always by the amount you may think.

i can see them inflating the results from thier own intakes...but the results for the non-TPIS units i would hope would be accurate.

least as accurate as just about any other article written by a sponsor supported party.

 

agreed...look at the number data i posted...

500+ hp...but barely 400# torque

 

Yeah, this is why I'll probably go FI to hit my goals. Lots easier to get big low-end torque with a turbocharger.