Kelly crazy D-max That thing launches crazy.

 

Now, I posted this number on the PA forum months ago. I thought I did it here but I cannot locate it in the search. Gonzo you may have read it. 799 is a LS6 head casting number. It is not the only number given to LS6 heads. Some are made in Mexico and some else where. I forgot the what the other number(s) were indicating an LS6 head. When PA comes back up I hope the search memory is still good.
It was confirmed by some of the great minds on the PA forum that 799 is a LS6 head. I am not sure why is is being doubted so much around the fourm. The Silverado brochure I read at the dealership mentioned the L33 as a H.O. 5.3 motor with higher flowing heads, aluminium block and so on. I'll be glad when someone gets to go through one.


While I am here. Some folks are complaining abot the L33 not running good down low. The motor, or mine anyway, is so tight when new it feels like the e-brake is on a bit when you push on her. I am at 5k now and she is running better everyday. Still no engine tic or slap (yet) either.

 

Can you get the optional L33 in a reg cab Z71 with the optional 4.10's? That would be a nice starting point.

 

Well reason number one for doubting it is because the chamber on the ls6 heads are for an engine with a larger bore than the 5.3 and 4.8. You wouldnt put a stock 4.8/5.3 head on a 5.7 or a 6.0 without opening the chamber bore first. It is also not a good idea to put a head on with a chamber size of 3.89 on to a block with a bore of 3.78. Also the compression would go down on these motors if you bolted a ls6 head on. Same thing goes for the 6.0 head to only the six liter head has an even larger bore than the ls6 head.

 

I was thinking the only real Ls6 head was the "243" casting

 

It has also been noted the L33 is slightly higher in compression than the Lm7, ala the Flat top pistons.
Perhaps the specs from an SSR would help. The L33 was in those early on I heard?

We need to make this a contest, to see who sleuths the L33's inner self.

What are the differences between the L33 and Lm7?
1. What are the heads all about? Are they LS6 units with smaller chambers? What are the CC's anyone? What kind of valves?
2. Compression Ratio? Do the flat top pistons make up for larger chambers?
3. How about the cam? Anything new there?
4. What actually contributed to the 15 more HP than the heads and pistons? Fans? Higher Flowing Cats?
5. Is it a placebo? Hype?

 

Here is what I think which dont mean jack.
Alloy block is the main difference
Heads are like the Ls6 ports but a smaller chamber
10.0 compression w/flat tops
Stock valves not sodium,dont need them do to the cam
more cam lift and duration over the LM7
with all the engine changes and the cooling fans I bet there is more than 15 HP difference on a dyno comparing z71 to z71
I bet it has more TQ managment holding back.I bet a tune will really unvail the differences.Mileage has to improve due to the closed off front end and the more efficent engine.

 

That's the stuff I want to confirm. Theoretically, if the chamber volume was the same as a LM7 head, how much of a benefit might be expected if the heads did have a LS6 style port and maybe a slight P&P job before they were put on?

I've found that most performance 5.3 heads have been reworked for larger bore engines, so to put them on a 5.3 is usesless. I hope that L33 heads might be a nice "budget" upgrade for us pedestrian 5.3 owners.

 

I wonder if they still have the small valves like the Lm7?

 

unfortunatly only the extended cab is getting the good 5.3.