changing cams

[923.4v6]

how big of a cam can you run with stock 3500 heads and springs with camaro 3.4 pistons?

[ForcedFirebird]

I can meaure for you Monday if you don't get an answer by then. I can tell you the yellow springs are solid stacked at .5613" of lift, lol.

I wouldn't use the stock springs on a big cam.

[923.4v6]

I was thinking about the comp 260.

[ForcedFirebird]

I was thinking about the comp 260.

You should be fine with that. Many guys use the 260 on iron heads with stock springs, and the 3x00 springs are much better. The 260 from comp is only .469" lift with 1.6 rockers and 220 duration.

What are you doing for a tune? If you are tuning anyways, it might be better to use something with a little more duration due to your high compression.

[923.4v6]

You should be fine with that. Many guys use the 260 on iron heads with stock springs, and the 3x00 springs are much better. The 260 from comp is only .469" lift with 1.6 rockers and 220 duration.

What are you doing for a tune? If you are tuning anyways, it might be better to use something with a little more duration due to your high compression.

I just bought ostrich 2.0 the chip burner and datalog cable I know a guy that is supposed to help me with it. I just dont want the valves to hit the pistons. A friend has a crower cam not sure about the lift I can use for free, but I would reather buy a new cam to be on the safe side thats why I was wanting to know the max. size I can go with the alum. heads and rwd pistons.

[ForcedFirebird]

You don't have to worry about the 3500 valves hitting the pistons in your engine, any more than 3500 valves hitting in a 3500. Both the 3500 and the 3.4 pistons stand ~.010 proud on both. The contact point on them both are outside the dish

SOOO, if you look up some of SuperDave's old posts, you'll find pics of where he had contact. His cam has over a 300 advertised duration, so you should be fine with a 272 or more even. You should concern yourself more with valve float using the stock springs with an aggressive cam.

[923.4v6]

I have a new set of the spring you see on this head, I bought off ebay a few months back but after seeing where they were made I was afraid to use them. If you think there good what seats and seals would I have to use?

[ForcedFirebird]

What do you mean "where they were made"?

If those are the LS6 springs, then the LS1 seats are fine, you might have to open up the center hole with a die grinder to fi the 3500 heads. Use seals from a 1991 Cavalier 2.2L (FelPro part number SS 70816), you'll need two packs.

As mentioned in that configuration on the 3500 heads, I measured a solid heightt of .5613" and you should be fine with up to .520" lift or so.

[923.4v6]

they were made in germany but advertised as oem.

[Superdave]

those have the same tags as my old yellow LS6 springs.

they're good for about .510 lift, and will handle that H260 cam without a problem.

[923.4v6]

Well, I just got hold of a crane 272 to use for free. Now can I use it with the yellow springs without any worry?

[gectek]

they arent "advertised as oem" they ARE OEM just made over there by another supplier. did you really think that GM made all their own parts or that all of them were made here? the LS springs are just fine...except for this one...http://60degreev6.com/forum/showthread.php?t=40983

[923.4v6]

I just thought that gm would made them in the us.

[923.4v6]

I'll give them a try with the 272.

[ForcedFirebird]

As I said before, so long as those springs have the same stacket height (coil bind) then you are goo to about .525" lift without problems.

You may want to use the stock springs for cam break-in with the lower seat pressure to avoid wiping a lobe. I went straight to the yellow springs on a new cam, we'll see what happens