Wow, so 2.02's will fit. Cool! So did you feel a big difference with the big vavle stage 3 heads on your 5.3?

 

Well...I did everything at once....radix, headers, heads, exhaust, intake, computer, transmission, pistons, ect....so HELL YEH I noticed a difference. But I don't know what to compare it to besides what it felt like to run 12 secs in a car.

Then I blew my drive shaft up...and it's been down hill since. I found out that I had a F-ed up head job after trying to figure out why I had a lean misfire condition. I didn't even get the 3 angle job and a ton of other bullshit. So it turns out I haven't even driven it with a true Stage 3 Head job. Well, I am putting it back together today and tomorrow...so I am sure it will be tight...and fast. But...they fit.

 

If you can bairly fit a hair inbetween the wall and valve edge, think about air trying to enter and exit the chamber. Might be working against yourself.

I've read that some of the pro's shoot for .20 clearance, but its not always needed.

 

Good point, and even on the other side of the 2.02 valve is a cylinder wall. I'm not sure on the exact clearance, but I'm willing to bet its close! I guess the real question now becomes: What's better, bigger valves at the expense of more shrouding? That's something else to think about.

The pro's probably use that figure with thermal expansion in mind too.

 

Here is (reaper)Wes' set of TEA heads he had worked. 2'' & 1.55, I believe.

Yeah, you can imagine what a 2.02 would look like with a 1.6 ex.

yikes.

 

Even The 2.00" intake valve is very shrouded on the stock bore. If it were me, I would just stay with the stock valve sizes, I wouldnt even touch the chambers to help keep compression up, Mill the heads .020-.040 and just clean the casting from the ports. If you remove too much material, it will hurt you more than help you. Remember, Our cfm requirements are lower than those for the 5.7 and 6.0 . Also, I had a friend who went with 2.02 and 1.60 in/ex valves, he is taking the heads off to start over, that is just too much for the 4.8 and 5.3 IMHO.

 

Do they make a 1.94", that might be a nice compramise. I know they make them for the Gen I and II heads.

 

Yeh, no argument from me. When I bought the idea of 2.02's and eventually got them I hadn't really researched well enough yet. My cylinder is bored out 20 thousands helping maybe a little. But once I got them and started getting around on the forums and talking to a few motor heads, the common thought was they were probably a little overkill for the 5.3 and wouldn't be surprised if they heard of seating issues. Most speed shops though support the idea with their "quality" porting and seating work(obviously to make more oney). Vote is still out. I'll let you know for sure in a week or two of running them.

 

Would the lip cause a turbulence in the chamber, you think? Because now, the chamber area doesn't match the piston.

 

so how much should a standard port and polish and clean the chamber a bit cost?
and no one can give me a horsepower figure for this?