1998chevy1500

Ok, so that scratches off the OMTC for sure. So many options so many decisions.

Assuming that the LS6 springs should not be used on anything buy a stock LS6, my next choice would be the PAC 1218 or 1518. Both of which are rated the exact same except for the 1518 being capable of 0.050" more lift.

For the sake of conversation lets say I went with the PAC 1518. My research suggests that with any of Comps XE, XER, XFI lobes these springs should last indefinitely. http://www.ls1.com.au/forum/showthread.php?t=88823

Being that I haven't yet found a cam that fits my needs exactly I am already assuming that I will have to have the cam custom ground. In the end I will probably have to consult a cam expert, but I would really like to have my ducks in a row before that phone call. Improving on the feedback that I am getting here and in PMs I have a hypothetical custom grind in mind using Comps "Xtreme RPM for LS1 High Lift" lobe from their catalog. 212/218 .558/.563 115+4LSA. This is simply their XR265HR Hi-Lift with 4* of advance. The wide LSA should give a nice wide power band and idle, while the 4* of advance should help by moving the torque curve down lower.

GMCtrk

iTrader: (27)

The 212/218 high lift would be a perfect cam. There is no need to go over .600" of lift as the stock 317 heads aren't flowing any more at that point anyways. In fact, they lose flow at that point. So you would only be stressing your valvetrain at that point. I run the PAC 1218 springs, and for the price you can't beat them ($125). I recall a member here who had a 212/218 in an otherwise stock HD and said it was a blast to drive.

1998chevy1500

From what I have seen on this site much over 0.500" for either the stock 317 or the stock 243 (which I hope to swap to) and there is very little gain in flow. With that, I would probably have very little to gain by going to the Hi-Lift version, but also I would have nothing to loose, epically if I was running the PAC springs. So, PAC springs and the Hi-Lift version of the 212/218 lobes. Pretty well settled there, thanks for the help with that part guys. :handshake:

Now I guess the questions progress to LSA and advancing the cam. I am thinking the 115 LSA should make for a nice idle while also giving me a smooth wide power band. The 4* of advance should bring the power curve down in RPM, hopefully to the idle to 6k usable area. Thoughts??

I am very glad to hear that the off the shelf 212/218 is a blast to drive w/ a stock 6.0L stock 4l80e. Hopefully my slight derivations from that cam should work out for the better.

While I am here asking cam/valvetrain type questions... Lifters? Get new while the heads are off, or keep running what I've got? I have 110k on the truck right now. Pushrods? With a more aggressive cam I should be getting a stiffer pushrod correct? Stock is 7.400, 7.425 a good number to keep valvetrain noise down? I know I should really measure the rod length needed, but a 7.425 is usually a good choice for those too lazy to measure correct?

GMCtrk

iTrader: (27)

that link you have is incorrect on the 6.0 flow numbers. The 6.0 flows almost identical to the 243 LS6 heads, maybe 3 cfm less up top. This is by testing from WCCH.

sonoma43

iTrader: (1)

7.4 usually unless milling the heads, or changing head gasket sizes, with most of the comp cams a 7.4 rod is recommended

GMCtrk

iTrader: (27)

You will want to measure the base circle of the cam when you receive it, or simply call comp and ask. Typically, aftermarket cams will have base circles, .050" smaller than stock, so you would need a pushrod .050" longer than stock to compensate for that. 7.425" pushrods would be a good choice.

1998chevy1500

Well darn, looks like I will have to quit referencing that in my posts. On the plus side, the only reason I would be going for the 243 heads is to bump up my compression ratio. If anyone knows of an easier/cheaper way to bump up the CR ~0.5 w/o pulling the motor to put new pistons in let me know.

Well, being no head work is being done, all I will have to do is talk to Comp. Awesome, easy. Is the base circle measurement a diameter? I would assume so because 0.050" smaller /2 = a 0.025" longer pushrod needed.

Lifters? 110k on them, would they make it to 200k with the new cam? Based on everyone reuseing them I am going to assume yes?

ap2002

iTrader: (8)

I used to have the 212/218 (.558/.563) hi-lift version but custom grinded on a 114lsa, it was on my 01 ecsb 5.3 z71 with 285's tires on it.... this cam woke up the truck big time, i ran it with the LS6 springs and never had issues, plus the stock quite valvetrain was a big plus..!!!! a cheap way to bump up compression is just take your stock heads off and get them milled, its usually around $80-$100 at a machine shop. i also was running stock size pushrods 7.400, but if you are going to mill the heads then its a good idea to buy a pushrod checker... dont worry about lifters... this same cam went in my brothers truck after i sold my z71, his truck had 120kmiles when the cam was installed, i know it has 30kmiles more on it now and still running strong!

sonoma43

iTrader: (1)

go to a thinner head gasket to bump compression.....its the easiest way

1998chevy1500

Was there any advance ground into this cam? What other mods were you running? Mainly looking to see if you had a higher stall torque converter or not. You mention LS6 springs giving you a quieter valvetrain, are you implying that the PAC springs will make for a louder valvetrain?? Fill me in on all you feel like talking about on the setup you had. Being that my truck is a daily driver, it would really hard to live without the truck while the heads are being milled, that and I would have to find a good machine shop around here.

Can you actually get a thin enough head gasket to bump up the CR a half a point? You have some companies that make thinner gaskets? Thus far in my searching I have only seen stock MLS type gaskets.