[Vettezuki]

Originally Posted by BRUTAL64

Old timer!!!!!?????. Fine I see how it is.

I meant that with the deepest of respect yo. I grew up around old people, namely my pa who is 80 now. Not only do they say the darndest things, they know stuff from being around that I don't. That's what I meant.

First thing that bothers me here, is that fact (with info you gave me) you do not have enough mechincal compression to ping with an all alum engine and the cam you have.

That's why I'm quite suspicious about the real specs on the heads. All I know is that they were 4.8L truck heads that were milled and majorly ported. I don't know the mill specs.

So why does it ping? Cylinder temps causes ping. So first we have to lower cylinder temp. I would start with lowering the overall engine temp.

I would run a water spray into the engine to clean all carbon deposts out.
Yes, you can do that with engine running. We'll talk about that Sat night.

I've run Sea Foam (nasty solvent) into the running engine right through the intake. I've done this on some cars like my brothers Tacoma, and holy mother of god the crap that came out the tail pipe for like 30 minutes was amazing, and it absolutely ran better after. On the Vette, almost nothing. Given the nature of water and heat and the nature of aluminum, water spray scares me a bit, I ain't gonna lie.

Second is fuel air ratio. A lean condition will run the cylinder temps up.

I'll look for my sheet from the last pull. It's on Vettemod I think. It's totally in line with Gen III idealized A/F curves . . . according to the pointy heads that saw it. Certainly leaner than the olden days of carburated iron blocks Imma guess'n.

Next is a lower (cooler) plug range. I'd drop two ranges down to start.

What's two ranges lower than Iridium?

I really want to know if the full advance (given) is correct. This is VERY suspect from what I've seen so far.

I'll see if I can call the tuner and have him pull up the program. I just remember that he was fairly surprised that's all he could put in. I want to say he expected to put in like 32 degrees???

Lastly pull the heads and we'll clean and slightly reshape the chambers and smooth the piston tops. Yes, I said "we". I don't work on other people's motors anymore. But for you, I may just come out of retirement, to do the chamber shape correctly. Not pull the heads

This sounds great. I was planning to put headers on next year, maybe spring or so. If I'm going to pull the heads, I think I'd like to put the Sodium Filled valves I have in, change the rockers to some gucci ones and maybe even the lifters to those trick Caddy ones developed for their racing team. Poof, we're talking some scratch now. I'll pay you in all the beer and pizza you can handle . . . after working.

NOTE: The tuner offered to retune my Vette for free. To be honest, the place we used was having some screwy issues with its A/F equipment. It took all day and he said usually he can dial in an LSx in a couple hours and like 5 pulls. I did over 20. He said he got the best it could be at that time, but offered a free re-tune cuz he's a swell guy. When we dynoed at Dynamax, Richard said it had been well tuned so I don't suspect bad tuning, but something fundamental with the engine setup itself, namely higher than advertised compression . . . My point is that I wanted to do these other mods like headers, rockers and maybe lifters, before retuning. I'm also running Torco now, and that's ok. I wasn't running it during the original tune. I'd love to get to 450WHP on my N/A 346 so I can harass Sean and his pullied Cobra even more.

Finally quench--I've actually raised compression to close the quench to .045 to get the pinging to stop. This is VERY true. Quench is a VERY big deal.

Ruh-roh. Que es quench?

I'm not saying your info is incorrect-but any minor error could lead us in the wrong direction.
It is important that the specs you gave me are correct. This is the key to any mods we do in the future. This is a disclaimer or sorts.

Hell, I'm saying that it's at best incomplete.

Do you have any pictures of the chamber shape of your head?

I'll check but I don't think so. I remember they were gal durned big and rectangular. The assembler and installer of my swap (ls1z28) said they had gone absolutely as far as they could with the porting as I recall.