Here is my situation..... I am planning a LS2 based 402 swap into the bird prolly next winter and am in the process of picking up a few parts. I had been planning on just getting the chambers opened up on my "worked" TFS "as cast" 220's but ran up on a set of L92's CHEAP. If I got them I would prolly get WCCH to port them though I am not sure what it would cost to have them done and set up but I am guessing if I sold the TFS I would have $500-$700 in the L92's.....

My TFS flow about what the CNC'ed ones do on TEA's bench at 322.9/282.7 (I know the exhaust seems REALLY high). I realize the L92's flow much better on the intake side but not sure if a little 402 can actually use it????

What are your thoughts.......???? Which heads and why???? Oh.....goals??? Make as much streetable power as I can.....

 

What do you have for an intake now? The L92 heads can flow a lot of air, but the intake is still a restriction. If you pony up for the latest FAST offering, you stand to gain more over an L76 or LS3 intake, but at what total cost?

If you already have a FAST for your current setup, it seems you could make good power optimizing what you have through proper porting. If you are still using an LS1 or LS6 intake, you might as well take the leap. Just be aware that the cam selection is a little more of a challenge. Look to others who have already had success with combos that appeal to you.

 

I have an unported FAST 90/90 now that will be upgraded to a 85mm MAF and 85mm FTP lid and get get the FAST ported. My tuner says that alone will put me around 450 on his dyno. All your points are well taken.... I believe the reason the L92's aren't kicken *** over most everything is they are intake limited..... though now there is FAST for them like you said.......That is another $900 so.......Yeah I know I can sell my 90/90.......

I just wonder does a pretty agressive 402 need more than the TFS heads can flow.... I see some nice #'s from these heads on the smaller 402......

 

I will never utilize a stock casting again in a build. Too weak unless you are just doing bolt ons. If you want to make power reliably, get aftermarket heads, I have 700+ rwhp 408 with 243s and I'm now on Darts and it is a big difference.

 

700rwhp out ot 408ci is 1.7hp/ci at the wheels. That roughly translates to a 590rwhp 346, which doesn't happen N/A. What else is behind your number?
I have seen great results from worked AFR 205 heads on 402-408 engines. I can't imagine the 220 heads being a restriction. Once you have all of your parts ported and matched to your particular combination, a cam with the right valve events will get you there.

 

He might be able to make that much with a solid roller turning high rpms. It would be hard and not very streetable though lol

 

lol, hey detective, i never said anything about na. it puts down 530 rwhp na, then there's some nitrous.

 

Let me know before you put your 90/90 up for sale. I wonder how different they would flow if you went with a Victor Jr. intake setup and a SD tune?

 

Guy (OP),

You recently switched to a larger head and while you felt the notable increase in top end power you also noted concerns it felt softer at low RPM's cruising on the street etc. and was disappointed with that trade off.

IMO, the L92 swap is heading even further in the same direction so be prepared.

I have a customer I helped awhile back (a 402 CID combination) that ran a set of my ported 205's.....with a 243/247 cam (not huge), it made low 500's RWHP and high 400's RWTQ on a Mustang dyno and still had a heavy clutch, stock water pump, and wasn't what I would call a completely optimized set-up. Car weighed 3750 with driver (6 point cage and no weight reduction mods to speak of) and it went 10.85 at 128 and some change trap speed. Per my customer, even in the worst track conditions (heat of the summer), he never ran slower than 11.20 @ 126+.

His buddy built a similar combo around a set of ported L92 heads and a slightly bigger cam....while his buddies car made slightly
more peak power, it took more RPM to get there and was missing 50+ RWTQ under the curve.

Also, driving the two was night and day....the AFR headed car felt alive and ready to explode at ANY RPM, where the L92 headed car was very lazy under 4K. Per my customer he said any contest of acceleration on the street was over quickly when they both ran. I'm not sure if his friend actually ran his car at the track but I will get that information if its available to me. I'm also trying to get an overlay of the two distinctly different power curves but the key to my entire post is to realize that none of this shows the difference in part throttle operation and engine responsiveness....that's where the high flow, high velocity, small port shines....especially at lower cruising speeds. You will never be evaluating any of this comparing WOT dyno results. You would need a load cell type of dyno that could register torque output at various part throttle loads and throttle position to really compare (and suffice to say that never happens).

BTW, Im posting this info with the owners consent but he tends to street race this car and doesn't want to publicly show his hand by posting any of this info himself. He's thrilled with the package I helped him set-up and was totally cool with me sharing his results.

Im working on the overlay graphs....I personally haven't seen it yet but would really like to.

-Tony

PS.....Here is a complete list of the mods in the package I am referencing that I copied and pasted from one if his PM's....I forget to add that power was put thru a heavier 12 bolt rear as well.

BTW, Im posting this not so much as to hawk or try to sway people to buy an AFR head (or an AFR head I rework by hand), but more so to make a point that when it comes to cylinder heads, bigger is not always better, especially when we are discussing street/strip applications in fairly heavy cars. A very efficient high flowing smaller port can make more power than most think would be possible. Think about the results I just mentioned (not to mention other strokers I have helped with the same heads).....his buddies car had an intake port that flowed some 50 more CFM (huge disparity) and was probably 60 cc's larger after the porting work. With the same displacement advantage they both made almost the exact same power on the exact same dyno and the AFR headed power curve destroyed the bigger port across the lower and middle RPM's (increasing the engine's average power output considerably). Combination is everything guys and bigger is not always better.....

Sorry for the long rant.....if any of you are still reading (and you care....LOL), here is that list of mods on the AFR headed F-Body in question

402ci 11.5:1 compression
6.0 Iron Block
Eagle Crank
Howards Billet Rods
Diamond 10cc dish LS2 piston
Katech C5R Timing chain on cloyes hex adjust sprockets
Pat G Cam 243/247 .624”/.624” 114LSA +2 advance on a LSL lobe
Yella Terra 1.7 rockers
AFR 205's Worked over by Tony Mamo
Fast 92 ported by Tony Mamo with a 90mm TB
Fast Toy's 85mm lid
SLP 85mm MAF
Edelbrock 1 3/4 to 1 7/8 Headers
SLP Dual Dual Cat back with Cutout
Monster Stage 4 Clutch with billet steel flywheel
Strange 12bolt 3.90 gear with a spool
BMR TQ Arm, Control Arms & Panhard Bar
F-series QA1's all the way around
Tom Z wheels Z06 motorsport knock offs (aka HEAVY) 275/40/17 MT DR's
Six pt mild steel cage in it as well.

 

Drag racing and raw power, L92's but it seems the smaller intake port heads would be more fun for a street car.

 

great info from Tony, a lot to read though j/k

 

But what if that street set-up (which is alot more responsive and fun to drive) actually out ran the larger "drag race" set-up?? Thats the point I was trying to make and it actually happened in the real world comparo I briefly described above.

Your making the assumption the larger "drag" set-up would take the win light at the track and that is not always the case and it represents conventional thinking (for lack of a better description) which is sometimes flawed. You can have your cake and eat it to with the right street set-up if you build it properly and select the right components.

My former 346 with the 224 cam is the perfect comparison. Almost five years ago I was knocking down 475 - 480 RWHP.....a number most of the bigger headed larger cammed combo's weren't even producing and I did it with perfect driving manners and a crisp and responsive package.

And it would have knocked off nine out of ten H/C stock displacement cars at the time regardless of whether they had a "drag race" set-up or not.

Again.....it goes against the grain of conventional thinking.

-Tony

 

va speed has l92 headed ls2's w/ported l76 intakes making 500 rwhp. there is hardly any to no gain over a l76/ls3 intake verus a fast 102. you'll save a ton of money going with l92's & a ported l76/ls3 intake. I'm currently having a lsx454 being built with these heads & intake.

 

Not to hijack the thread but how did you make that kind of power with that small of a cam on a 346? Lots of Porting on the heads and intake?

 

Attention to detail and the right combination....its ALL about the details.

Perfect header, lightweight clutch, ported FAST, cam degreed, UDP, EWP, efficient CAI, etc. etc.

The heads were actually out of the box 205's....

Here is a more recent independent results from a customer I helped who wanted to mimic that combo but we decided to get a little more aggressive with the cam (a 228/228 versus a 224/228) and he also opted for me to port his 205 heads in an effort to grab all he could when the smoke cleared. He produced 500 RWHP with this set-up slightly besting my realistic expectations heading into this but he invested the better part of a year perfecting the tune and the entire combination.

Lets keep the OP's thread on track by PM'ing me if you have any questions concerning the thread below

https://ls1tech.com/forums/dynamomet...-500-rwhp.html

Also, there is plenty of info on my older 346 CID 224 cammed package if you use the search function and dig into threads I started a long time ago (04' - 05')

-Tony

 

Thanks for posting Tony! I think you are right as always LOL...... Kevins build (WKMCD) got me a little starry eyed about L92's but it is apples and oranges since he has more cubes, lighter car, more gear etc.......

Anyway thanks for sharing your thoughts and an informative post

 

Hey, nothing personal - your previous post didn't really explain the difference between your 243 heads and the darts you currently run. You haven't listed any other details on your setup, but 530 at the wheels n/a is a nice number.
Kevin's build certainly put up some nice numbers, and apparently drives great as well. The guys at VA Speed really know their stuff, and I am sure they could steer you right if you choose to go that way. That said, there really isn't any cost savings advantage to the low-buck factory castings when you go to a build of that caliber though, and picking and choosing based on budget alone is a roll of the dice.

 

Yeah I definitely don't have the $$$ to put into this buld like kevin does. I think this build with a well speced cam and some other upgrades like a ported FAST 90 and bigger MAF and lid could make 525+ streetable power. SD tune am also considering... HKE is gonna do the short block and I'll let Erik spec me a cam. I want Tony to port the FAST if he will. I would like to see mid-low 10's on a full weight car.

I don't DD this car But in three years I have driven it to Orlando, Atlanta, DC twice and Ohio twice so I need it be decent to drive on the street and more importantly dependable.....Might get a wild hair and spray it if I get bored with it.....

Any way thanks for everybodys input I and I hope to have my $$$ up for the SB by July and go from there. I wanna upgrade my TC too to a Yank PT series because this motor should spin 7K so i can take advantage of the higher shift extension of the PT series. Not a max build but just wanna fast really fun streetcar....