jeremym

iTrader: (3)

I have a 414 stroker with a FAST intake and stage 3 LS6 angle milled heads. I am thinking about getting a L76 intake with some ported L92 heads. Should I see a gain in hp and how much of a gain? I know the heads flow good but does the L76 flow good or do they only flow like 305cfm which will restrct the flow of the heads? Thanks for the help

WizeAss

iTrader: (5)

Sup Bro,

Like we talked on the phone..... yes, based on the fact that LS6 heads (even while ported) where created for 5.7ltr engines and a small bore. L92 heads are made for a 6.2 ltr truck motor and have much larger valves. You have the bore to prevent shrouding. These heads will flow over 330cfm with no porting, and they will also help with your compression and velocity issues IMO you have too much with big bore/stroke and milled heads. Only negative is that your current cam, as big as it is...... may not work with these heads. If your FAST is not ported it should flow equal to the L76.... yet if it is ported I assume it may do a little better.


Your heads and cam choice in my opinion are where you are having issues. You need to drop the compression and choose a cam based on the heads you choose to put in the car. Your cam may have more lift then the stock 2.16 intake valve can handle???? I am not sure.

Sale the Fast combo = 800 bucks.... buy L92's for the same. Sale your Stg3LS6's around 1500..... buy an L76 combo for 500 and a cam for 500 and spring kit and pocket the rest.

Hell you may gain 0 peak horsepower with this setup..... but you will likely gain power up and down the curve where it counts.

Do you have the graph of your previous dyno?

Knowing you...... (only Mexico street duty) I would look for 11.7:1 compression.

WizeAss

iTrader: (5)

also this is all based on what I have heard about your current setup.

WizeAss

iTrader: (5)

IIRC GM High Tech put an L92/L76 combo on a LS2 block (6.0 or 364) and made 547/495 on an engine dyno with a small small poorly matched cam.

With your bore and stroke and the right cam..... 650 on an engine dyno should be no problem. I think the 4.0 bore is smaller then what you would want for these heads due to the valve sizes...... hurts flow vs a 4.060 or even 4.030 bore.

With just the camshaft they made 502 on the dyno.

With your bore/stroke, the proper cam shaft, Ported L92's that flow over 350cfm, and L76 intake ..... making over 670 engine dyno horsepower shouldnt be that difficult.

Beast96Z

iTrader: (21)

I can only assume your running a stock LS2 block with a 4.100 Eagle crank. In this instance, I would wait around awhile before i went with the L92's on a 4" bore. While magazine articales are nice, I don't lay alot of claim into them. These heads/intake are still very new to the market, and finding a cam that will work will also be a fun challenge. I'd wait for a few vendors to complete some testing on diffrent bore sizes and camshafts before you dumped your current combo. A ported FAST and a nice set of ported LS6's should easily make great power. If your chasing gremilin, get those worked out before you swap anything. Details on the motor would also be nice. (cam size, power, etc...)

Ryne @ CMS

iTrader: (10)

hmm..... no dude, i think he has a iron block .060" over and a 4 inch crank think about it sir

WizeAss

iTrader: (5)

yep... that is why the L92 setup is better for him. I dont think putting ported LS6's on a bore/stroke motor is as good as longer runners and a better flowing head.

Even on his assumption that it was a 4.1 and 6ltr block..... the L92's gained 45+horses on the stock LS2 heads without going to 12.2+:1 compression!!!

jeremym

iTrader: (3)

Mike, I have a new cam in it now and it runs perfect.

jeremym

iTrader: (3)

It is a 4.060 bore w/ a 4.0 stroke and the cam size is 244/248..612/615..112LSA. With this new cam I put down 535rwhp w/26*of timing

WizeAss

iTrader: (5)

IMO that cam will work with the L92's... since the lift is low and it does have a split....... I do think if the exhaust duration was even bigger it would still work.

Good cam.. Do the swap! Get the heads ported, and wait for Manley to get those valves to the market.

No one has a clue how that cam would do with those heads.... since the only dyno'd combos have small or babyish cams.

WizeAss

iTrader: (5)

also I havent seen your curve.... 535rwhp with 26 degrees is good power..... but at what cost? what is the compression? I always thought that that much timing and those LS6 heads you would be needing non pump gas?? Am I off on this assumption?

Beast96Z

iTrader: (21)

Well ****** ****! I forgot all about that super common .060" over iron block. Guess my magic lamp missed that one. I don't have time to sit down and do cubic inch calculations to try and figure out peoples combo's. I just threw out the closest thing that came to mind. If your so GD smart, why don't you try helping people instead of wasting space. As simple 4.060"x 4" would have been very sufficent. My apologies to the original poster for the rant.

While I'm here, L92's are still a bit new. If you want to take the dive on what a magazine did, that's your choice. If your rollin 535 rwhp, I'd say your doing fairly well.



And you know this how? Your going purley off assumption. How many L92 cars have you seen run?


I don't totally agree. A ported LS6 head is a great stroker head. What do you think all the fast cars ran before all these aftermarket heads came out? There are still plenty of cars out there laying down killer numbers with LS6 casting. The car in question is one of them. A 535 rwhp car is excellent w/ LS6 heads.

The power gained was more around 40 horses, and it was measured at the fly wheel. Hardly impressive if you ask me. May be nice if you are looking for cheap, mediocre gains, but hardly worth the swap if you already have LS6's. If the LS2 heads in that article would have had just the minor touches done to them, (bowls cleaned and valve job), they would have easily surpassed the L92's. Who's to say what would happen when you put them on a higher compression, bigger bore motor, but I'm sure they would do fine. It's just assumption at this point. I can only assume that the chambers of the LS6's were opened to match the bore of his motor. If so, when comparing a nice ported LS6 to a stock L92 casting, you shouldn't see much to any diffrence. You may even loose.

WizeAss

iTrader: (5)

his heads flow 305cfm..... stock untouch L92's flow 330cfm with no work.

he has compression issues. L92's sound better to me. Even if he lost power peak.... I think he will pick up more.

Best thing for you to do Jerm is wait for more dynos and cam combinations to be proven.... then make this decision.

What issues are you having now and why do you want to swap. IMO if you made the swap you can lower the compression and be a tad bit safer with big spray.... if the pistons are setup for a 200 shot.

Beast96Z

iTrader: (21)

If he needs to lower compression, maybe a thicker head gasket would help. Maybe some info on what the problem is and if it is still occuring would help. Seems from the earlier post that the problem may have been corrected by going with the bigger cam, thus lowering DCR. Your second sentence is all I reccomended. I'm not saying he wouldn't gain with the L92's, but I don't think the gains would be enough to warrant the swap. If he were going to ported L92's, then that may be diffrent. Personally, I'd just wait for more results.

jeremym

iTrader: (3)

I have no issues. I was just wanting to know if I would gain rwhp with the swap.They will be ported L92's.My comp is around 12.5 so I cant run more timing then 26*.So if I swap out the set up I will go for 11.5 or 11.75 comp so I can run more timing like 30 * or so. FAST w/ported LS6 at 12.5 comp 26* vs L76 w/ported L92 at 11.7 comp 30* which is better for all motor(NA) on my set up.

B18CYA

iTrader: (17)

just let me know when, I will trade you up even up all my L92/76 bs for your guarunteed proven fast/Ls6 stuff

WizeAss

iTrader: (5)

what do your heads flow? I assume you wont lose anything. You should gain better compression which means pump gas wont be an issue. adding a shot of nitrous on the setup will also be better with less compression. Nitrous likes compression but I wouldnt run it on 12.5 with pump gas. If your heads flow less than 350cfm i dont see why not. but if your cam is not properly matched to those L92's you will likely not benefit. I think you have a nice big cam in there. The lift is not crazy but it has alot of overlap.

Gasket wont help his compression as much as the head swap. if you are looking for a gain of 40 or so horses I dont think you will find it with the swap, the curve is where you are going to be focused on. Too bad this is all too new to answer your question.

Ryne @ CMS

iTrader: (10)

dont your panties in a bundle.... i just thought a guy of you ls1tech knowledge would know better, considering you do give you .02 cents anytime you get a chance.

Beast96Z

iTrader: (21)

Sorry for the rant, I just took it the wrong way. When he said 414, I automatically thought of the LS2 combo's since most of them come in that cube range. You don't see to many people with .060" over iron blocks, so it was the farthest thing from my mind.

jeremym

iTrader: (3)

Will my kooks headers fit with these heads? Do you think a mizfit sheet metal intake will be better then the L76? What all do I need to change my set up to this new set up.Can I use my NW TB,fuel rails,valve covers etc,etc,etc?????