I'm looking to build a engine for my car and wanted a LS7 at first, but now it doesn't look like the smart way to go. Wanted to go with a LS7 block with ET LS7 CNC ported heads and was told I should be expecting high 500's at the wheels. I saw in another thread that TSP made 570rwhp on a 418 L92 with ported L92 heads and I'm sure it costs a lot less than a LS7. I know HP numbers don't mean everything, but why a LS7? BTW... does the LS7 intake manifold flow a lot better than the L76?

 

Starting a build myself
ETP heads
4.125 bore
Getting it done in my home town
Vengeance was an option as my son lives in Ga. and we visit there.
I decided to let the local guys do the work.
I am using ETP 4.125 LS7 Heads.
We have the best vendors right here in Michigan
John

 

Why does everyone automatically jump past the factory ls7 heads?? They will support more than enough for any street car. There have been far more cars put 600+ to the wheels NA with the factory ls7 heads than the ETP LS7 heads. This is not a dig or anything against the ET stuff, they have their place, but for a NA motor, IMO the factory heads are more than enough...

 

Yep they are great for the stock cam ls7
Its the Titainum valves and Lash caps .

Valve seats for different valves I understand have to be replaced.

 

I am building a Warhawk 427 with LS7 heads and intake. Stock GM. 238/254 .598/.610 112 cam. I also have heard the talk about the valves and such. When I talked to some of the perfomance shops nothing has been mentioned about the valves.

I s there anyone that has had experience with this issue. Not what anyone has heard.

Thanks

 

You can change the valves in the stock heads also...

 

I was thinking 427 heads were the best, and at $2600 CNC ported, with Ti valves, that's really a bargin. Ten years ago I paid over 2X for that same setup on a small block.
Today I ordered a set of L92 heads. For $800 a set I have room to do some work, and if I break something, I can afford to buy another set. I'm going with a L92 block and 4.0 crank, 415 inch, same logic.

 

what would be the difference in price between a ready to go and complete of

pair of gm ls7 heads complete with factory rockers

and

a set of etp heads complete with their rocker gear-

???

 

I'm not exactly sure but I think I was told they were about $2-300 less than ET's.

So what do you guys think? A LS7 woth the extra cost, or a 418 L92 would be just as good?

 

I would go LS7.But I'm just biased I guess?! Traver

 

THe stock heads have their limitations, that is why we build our heads with longer valves and structural integrity. rocker arm bosses dont break off, you can run any spring that you want, and they are not much more than a stock LS7 head, as far as the TI valves in the stock head, they have not much value, they are more of a liability.

 

Cary
there was a question about changing Valves in the stock LS7 heads.
I heard the seats were not compatible with Stainless aftermarket valves.

John

 

I would check out WCCH. Richard at WestCoastCylinderHeads will touch up the exhaust side of the factory LS7 castings and maybe a little clean up on the intakes. The intake port flows plenty already... the exhaust side just needs to catch up a little. They flow 360/250cfm+ afterwards. I have a set and they look awesome. I also had the spring pockets machined for larger 1.46" springs rated at .700" lift. Unless you are going forced induction or plan to spray a ton of nitrous... the factory castings should suffice. I plan to spray a 100-150hp shot without issues and rev it to 7300rpm. Harlan Sharp rebuilt stock LS7 rockers and the CTS-V race lifters are in it. I would say that is the main reason for wanting a thicker deck with the ETP castings IMO. No distortion/deflection with high cylinder pressures affecting the head mating surface to the block.

If the ETP heads are only a few hundred more... and offer the thicker deck. Go for it! The power is in the heads and your cam selection. It will leave options for the future wide open. ie forced induction/tons of nitrous.

The LS7 intake is the highest flowing intake for low/mid/high RPM's out there. Better than the FAST 90 and certainly better than an LS6//LS2/L92 intake. All the custom $3K intakes get smoked by it all across the board until you reach about 7K rpm. That is when a hand fabbed setup that suits the high RPM's starts to shine. The 6-9K RPM range. Anything below that RPM and the LS7 will kick it to the curb for overall HP and TQ. The LS7 intake is truly the reason why I went with an LS7 in the first place. It will still make power beyond 7K RPM and is great down low as well.

If the lash caps were an issue... you would see a recall from GM to fix it. They may not be optimal and do throw another complexity into the mix.... but if they were a problem... wouldn't the masses that own the new Z06 be having problems on a large scale?

If I were to do it again and didn't want a dry sump motor... I would most likely go 415ci (L92 block/4" crank) and ETP LS7 small bore heads with LS7 intake. You will save a few grand and essentially achieve the same results.

IMO the attraction of the LS7 block is the low entry price for a dry sump style motor. Plus the factory forged crank is well priced and will get the job done. I found out that if you swap in forged rods (Lunati ProMod billets) that aren't titanium like factory... the crank balancing is $$$'s due to all the mallory they have to use. If people are making 1000rwhp with factory cast LS1 cranks... the LS7 has more potential than that being a forged piece.

 

Is there any way a LS7 intake willl fit on L92 heads.? I thought the heads were made from the same casting.

 

No, the LS7 intake port location and bolt location is very different.

 

Thanks for the reply gnx7. I guess in the end the question is how much I want to spend. 418 L92 block... LS7 block... L92 heads... LS7 heads... ET... GM... too many choices! I'm actually thinking about just getting a crate LS7 from GM since it is the cheapest way to go and has a dry sump.

 

very good info here people-

 

What about the intake? With the L92 heads we have established that the LS7 intake is incompatible. Is the L76 intake the way to go with these heads or is the LSX 90/90 still the prevailing setup?

 

i dont think the fast 90 bolts on to l92 or ls7 head's

 

BLOCK: I chose an LS7 darton sleeve block for my application because a) I wanted billet mains w/o the high machining costs of adding them to an LS2 block 2) I can run up to a 4.190 bore. The factory dry sump will be run in my motor too, but you can do the same with the ls7 crank in a LS2 block from what I've gathered ( correct me if I'm wrong). I went with a cutom LS7 callies stroker crank for my application that allows me to still run the factory oil pump/dry sump system, but there are aftermarket application for the LS1/2/6 crowd to accomplish the same thing..but high $$$$$.

Heads: I chose to run the stock LS7's reworked by Richard at WCCH. Seemed to be the best bang for the buck for me compared to the ETP's. I'm replacing the stock exhaust valves w/ solid SS valves which will limited RPM to 7,500.

The ETP's look very nice but add Ti valves, Jesels and more and the price starts to build...it all depends on what you plan to do with the motor. For me, no power adder just N/A even though my beck intake is plummed for nitrous from John. That being said, I still may go with the LS7 intake once flow numbers are made on my intake, If its all above 7K I'll be using the factory intake.... reworked a bit.

FYI, my buddy runs his stock valves/bottom end LS7 Z06 to 8K all the time and has had no failure issues..other than his rear end and bell housing once slicks were mounted to it.

I think for all out race applications ETP, aftermarket forged rods and crank are a most. Then you would step up to a sheet metal intake to get that extra top end. I stuck with the stock Ti rods.

just my $.02