Revdoc

iTrader: (2)

I have been searching and learning a lot about the L98 and I have some questions about installing/selecting a cam. My original intent was to buy a small cam that would work with as much of the stock hardware as possible. After doing a lot of reading I am beginning to think it may be more trouble than it's worth.

First off, I have read that the stock springs are marginal for anything other than the stock cam. What is involved in replacing the stock springs with some aftermarket pieces like the Comp 986's? Do I need to remove the heads and have some machine work done, or is it a simple swap?

Second, I have also read that the valve guides themselves are a problem once you get much into the .500+ lift territory. If I replace the springs and keep the cam at or under .500 will I still need to mill the guides?

Third, I hear the stock studs are pressed in and will often begin to pull themselves out from the strain of higher pressure valvesprings. I have heard that one fix is to drill the stud and pin it in place, while the "correct" way to fix the problem is to have the heads tapped for screw in studs and use those instead. The pin kit is only like $10, does anyone know any pros or cons to pinning the studs?

I found this link: http://temp.corvetteforum.net/c4/vader86/cam.html which has a lot of specs for various cams for the L98 and LT1. One cam in particular that I'm interested in is the Accel/Lingenfelter 216 (216/218 .493/.501 with 1.6RR, 112 LSA). According to the link above it does not require machining the valve guides, is that true for my stock iron headed L98?

In the end I will be going with some aftermarket heads like AFRs or Trick Flows so I don't want to put much money into the stockers. I figure if I can swap the springs without removing the heads to have them machined, and if I can pin the rocker studs instead of having to get screw in studs, and if the above mentioned cam won't hit the valve guides, it would be a worthwhile purchase. Mainly for the experience gained by doing the work so it will be easier the second time around and to upgrade some of my stock ~90,000 mile parts in the process. I will be installing new rockers, lifters, timing chain, and water pump to go along with the new cam. Advice and opinions appreciated.

ta3ff

Redvoc, I feel your pain. Nobody cares about my thread either. Well either spend $300-$500 on upgrading your stock heads or spend the cash on some aluminum heads. Cams, I'ved followed the progress of some members here and most if not all switch cams about 3-5 times before their happy.

Also, prom tuning in a must with TPI. DUH!

Kevin91Z

iTrader: (1)

Buy the cam and the heads and swap them at the same time. The stock heads flow so bad and require so much work its not worth going to all the hassle of the cam swap with them, in my opinion.

You choice of AFR or Trick Flow heads is perfect, but if you're considering the 216/218 cam let me recommend the Comp XFI268HR-113 instead. Its a much better design.

Revdoc

iTrader: (2)

Thanks for the replies. I have found a little more info, according to what I read the valve guides become a problem at around .470" of lift

Since the valve guides would have to be machined anyway, it makes no sense to swap springs on the stock head or to try to pin the rocker studs.

Now I see why the LT1 cam is a popular upgrade for TPI guys. It's about as big as you can go on the stock heads without worrying about all this other stuff. Looks like for the TPI a cam swap pretty much necessitates a head swap, unless you want to have the stock heads worked over.

And I know I will definitely need to tune it. Luckily I have tuned a couple of LT1 cars and a couple of Megasquirt cars so I have the basics down pretty good. Maybe that will be one area I can contribue info to this site instead of just sucking it up like a sponge

ta3ff

Sweet! listen to Kevin91Z, He's got a pretty quick TPI. I'm going to steal most of his mods for mine. Sorry Kevin91Z.

His will still be faster, imo.

Kevin91Z

iTrader: (1)

Feel free to copy my engine. I'd love to see more fast thirdgens. Especially here in California. Its not tough to be clean, green, and have a fast machine.