I haven't seen any "proof" as to why they won't fit...so I thought I would post my own. I don't know if anyone will find it interesting, but I did...plus I got bored . Here are a few pics up the cylinder. It's kind of hard to tell from the pics, but I'll explain after the pics.

UPDATED....see post 22 overbore=open valves.







It's not the giant intake valve that is the problem. It's actually the exhaust valve that hits. The pictures are of stock L92 heads milled 20 on a stock bore LS1 (with no head gaskets). Both valves are open quite a bit also. You might be able to notch the side of the cylinder to allow the exhaust valve to fully open...it doesn't lack much. Now once it's all bolted together, I don't know if there would be any issues with the intake valve, but as it sits it fits. So there you go. They fit, but they don't.

Now the combustion chambers are obviously big bore also...so there is another problem.

 

I'm curious as to why anyone would want to install them on anything less than a 4.0 bore. According to many people "in the know", even if it were possible to run these heads on a standard bore LS1, you'd be losing power due to a BIG loss of efficiency.

 

Very interesting pics, thanks for posting them up.

 

All LS Heads will bolt-up to any LS Block..physically. This is the issue you run into with this Head..big Valves..lol

 

But, it's the "small" valve in this case...which I found interesting. I would have thought it was the intake valve that would give issue.

 

I know it's the small Valve..I own a set of L92's..

Even on the 4" Bore that Exhaust is like .050" from the Cylinder Wall..something like that.

The Intake Valve is offset on the Heads to help maximize air/gas distribution into the Cylinder.

 

I agree with a na setup...but what about a forced induction like turbo/supercharged setup??? I would think that it would be able to hold more compressed air than something like a 243 head therefore making it more effecient and the smaller bore size would make it even more efficient at higher rpms...your thoughts???

 

I can appreciate the posted pics, just for curiosity reasons. There's a reason why GM made a 6.2L block and put these heads on top of it. They simply have to have a bigger bore than a 5.7L. I believe that even with a 4.0" bore, the exhaust valve is still shrouded enough to leave power on the table...

 

I really found that interesting too. I would have though of the intake valve being the obstruction. I seen on the Edelbrock website that you needed to notch the sub 4 in bore to use the L92 head, and now you have the proof. Now I know it is big far as motor size due to valve shrouding, but I am kinda curious to see a dyno run what the curve might look like.

 

I'm not complaining with them..

 

Me either.

 

I'm no expert, but I would think it would be ESPECIALLY BAD on a turbo setup. Loss of intake velocity down low, crappy throttle response, slow to build boost.....but again, I'm no expert. I opted for a set of ported/polished 317 heads on my turbo build.

 

MAST makes the small bore versions and it seems they are on par with TFS 215s peak wise but sluggish in the lower/mid ranges

 

Yea, but for the price of the MAST heads, I would MUCH rather go with an aftermarket casting (AFR or Trick Flow).

 

I don't know why everyone is all about "bigger is better"


It's not. The sooner you learn this, the better.

 

^^


I guess the GM Engineers don't know anything either..

 

 

WOW!!! 3 post expert huh? I am sure that is why gm made the lsx block...really sucks having this ls1 maybe the 3 cylinder out of the geo would propel my car to 7 second quarter mile times

Here is the equation that most people use:

MORE AIR+MORE FUEL=MORE POWER

 

Ya that guy is funny..he drives a RX7 with a LS Swap according to his profile..

I guess a LS1 inplace of the little Rotory Engine doesn't fall under "Bigger is better" in his world.


Fail.

 

Those are some nice pics. How did you get in there to take those pics? Do have hands like the burger king tiny hand guy?

I don't know if they would actualy run very good, but it's interesting to see. Notching the block may not be impossible, but it looks like it would be in the ring area of the piston. I'd make it work and run it if putting an engine in was as easy as changing your clothes and I happend to have a spare block with L-92 heads sitting around.