RotaryResurrection

iTrader: (24)

Due to a bad lifter, I am replacing/upgrading several parts at once, including cam and valve springs. I am using the yellow ls6 springs. I got a 215/218 .545/.555 114 cam from jjz28.

Upon several recommendations, I went to sdpc for tech advice and parts. I pm'd "matt @ sdpc" on here since I happened to see his username and that he was online at the time, but never got a response (its been almost a week). I had trouble getting ahold of anyone via phone for 2 days, kept getting transferred and put on hold for several minutes, and once I did, they were not all that friendly/helpful. Getting solid answers to my few compatibility questions was like pulling teeth, and after asking a couple of questions to him the guy actually asked me "so what is it that you're wanting from me??". I had to come out and say "I WANT TO KNOW IF THESE PARTS FIT WITH THESE PARTS, IN MY ENGINE, AND IF SO HOW MUCH THEY ARE."

I told the guy what cam I am running (I am not sure he was really listening) and asked about valvesprings, valves, pushrods, etc. He recommended the manley hardened pushrods and said they would work with the cam. I got the package today and included were the manley 7.400 stock length pushrods.

Then while reading on here I find some posts where people say you have to run longer pushrods with the z06 cam, which is pretty similar to the cam I selected.

So, am I screwed on this project before I ever begin?

I also picked up the ls7 lifters and guides, head gaskets, etc.

I had read many posts on this forum of people saying you could run the ls6 hollow/sodium valves in these heads, but the guy outright said absolutely not when I asked about that. He also explicitly recommended against replacing anything else valve related such as keepers, seals, etc.

So out of curiosity, who is wrong...did I get bad information from sdpc, or are the posts on this forum wrong about the ls6 valves? Also, I found a post today that the yellow valve springs are insufficient for anything more than a z06 cam, even though I was told repeatedly they would be fine with the cam I selected. Any opinions on that?

I need to figure out who it is around this forum who really knows their ****, so I at least have someone reliable to ask when I need info on a compatibility question.

RandomHero

iTrader: (24)

Your post wasn't very transitional and also not very clear so I'll just answer the questions I feel like answering.

First of all with the pushrod issue. It's impossible to say with the information you gave us. Pushrod length is determined by the base circle of the cam. You could technically have a 250/250 cam but if it has a stock base circle cam you would use 7.400 pushrods. The reason why the z06 cams use a 7.425 or whatever they use is because the base circle is smaller than stock.

The ls6 springs will be fine for anything up to .570-.580 lift. Hell there are guys running cams with .600+ lift with no problems so you'll be fine with those.

3rd, are you swapping heads? There's no reason why you should be doing anything to your stock heads if you're just doing a cam swap. You don't need new head gaskets and there's no point in swapping valves for a stock head. Now with that said, there are plenty of guys who run 243 heads which are the ls6 heads with sodium filled valves

truckmann

iTrader: (8)

He is pulling the heads cause of a bad lifter and the heads have to come off to fix it.

I Agree with what you said about the pushrods and springs. Don't know about the sodium filled valves, or for that matter why you would want to bother putting them in regular old stock heads anyway.

RandomHero

iTrader: (24)

Ah ok then yea he will need all that stuff. I read through the part that he had previous problems(hense me first comment in my previous post). I don't really think you'd benefit from replacing valves. If you have time, I would find some used 243 heads and get them milled for your 5.3L. I don't think the stock 5.3L heads are worth replacing valves on unless you do some machine work on them.

RotaryResurrection

iTrader: (24)

Can you tell me how my post was insufficient in your opinion? I dont know a ton about GM v8 engines, but I am not an internet newbie and have about 15k posts on other car forums. As such I tried to give all relevant information that I could think of, including posting my signature with engine and mods.

To clarify, I have a 6.0 with the 317 heads. I plan to run forced induction later so I am not looking to increase CR. I was just thinking of changing valves because I would have the heads off anyway, and I did not think they were too expensive. IT was just one of those "while I am in there" things, about like the cam.

I was not aware of the difference in "base circles" on cams. In fact I dont recall having seen that spec quoted in any cam specs that I see being bought or sold. I did not get such a spec from jjz28 who I bought the cam from. I cannot find the thread in the FS section or my subscribed threads anymore, perhaps it has been deleted or something.

He was offering "regrind" copies of the 01 z06, 02+ z06, and 3 custom spec cams, and I bought the one listed above.

I guess I need to check the "cam guide" again to find out about this "base circle" specification and compare the stock specs to the new one once it arrives.

truckmann

iTrader: (8)

Unfortunatley the best way to check for the correct length of pushrods is to get a pushrod length checker. The tool is cheap, but you would need to install the cam and then use the checker to find the correct pushrod length. If you can find out the base circle of the cam and compare it to stock you can avoid this.

http://www.compcams.com/information/Products/Pushrods/

RotaryResurrection

iTrader: (24)

Bump. Thanks for the info truckman, that link was very helpful. I ordered a pushrod length checker. The cam came in today and the base circle is ~ 1.417 or so as well as I can measure it. Each lobe actually seems to measure slightly differently on the sides, some varying as much as 0.006. IS this normal?

I have been unable to find a solid answer as to the base circle of the stock 6.0 cam in my truck, and I dont have it out yet. I read in one post that it might be 1.617.

I am trying to figure out what size pushrods I might need to get, just as a guess, to see what the cost/availability will be. If I understand this right, my new cam is 0.200 smaller in base circle diameter than my stock cam, so I will need pushrods 0.200 smaller than the stock 7.400? I don't see any 7.3's or shorter being sold on sdpc, so I am not sure this is right. Anyone shed further light on this?

truckmann

iTrader: (8)

Well I don't know what the stock base circle is, but the stock pushrods are 7.400(think you got your numbers switched) and from what I can gather the z06 cam at the max has about a 0.050 smaller diameter. This means you would need a longer pushrod 7.450 to be exact. Of course this is all depending on what you actually have. I am pretty sure the difference isn't 0.200 cause I don't think anyone makes a pushrod long enough to cover that much difference. You could just buy a set of 7.40 and a set of 7.45 pushrods and then send the ones you don't need back as long as you get them from somewhere that takes returns.

RotaryResurrection

iTrader: (24)

Yeah, I got the pushrod numbers backwards but you are correct, stockers are 7.4 which is what I have now. I don't have the z06 cam but a custom grind from a shop. The base circle on this cam appears to be about 1.417. Each lobe is different, anywhere from 1.407 to 1.426.

RotaryResurrection

iTrader: (24)

btw I got the stock cam base circle number from this quote. I believe the 5.3 and 6.0 cams are the same unless I read wrong on this forum.

https://www.performancetrucks.net/fo...40&postcount=7