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What do I need to do? I'm rebuilding my 2000 LS1. I'm putting a Hot Cam in it and I have a set of 5.3 Heads. They are casting number 706. I've got LS6 Beehive Valve springs and I'm upgrading the intake valves to 2.02 or 2.08. I've got an 80mm throttle body and am using a typhoon intake. I'm curious about compression as I'm rebuilding the bottom end as well. Stock crankshaft with h-beam rods. What should I do about pistons. I don't want to have some much compression that I can't run on 93 octane.

teke184

the heads alone will boost compression.

and a thinner gasket will as well.

i'm curious why you're putting all this work into the heads and bottom end, but still planning for an ancient technology camshaft like the Hotcam.

you'll make more power on a better cam, but still lose nothing to reliability.

what are your goals?

Marc 85Z28

Don't bother with either the HotCam or the chinese Typhoon garbage. The rods and pistons don't need to be touched for those heads, but if you're in the engine and can afford it a set of forged pistons is a good idea. You can run up to around 12:1 on 93 octane, with 11.5:1 being a more practical limit, stock pistons or not. Those heads alone will put you well under that, around 11:1 depending upon the gasket.

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As far as the compression goes, I'm not against raising the compression, but I don't want to raise it to the point of not being able to run 93 octane gas. The cam I bought a while back because I got a hell of a deal on it. I was going to use it in the 02 car before I sold it. I know there are newer, better technology cams out there, but I have this one. I'm willing to use a different one. I'll tell you my goals and maybe get some recommendations.

I want a strong lower to middle power band car. I want to be able to run high 11 1/4 miles but have a mean street drivable car. I'm looking for a nitrous kit as we speak but I don't want a cam that needs nitrous to wake it up. I'm going to get the car tuned so I'm not terribly worried about not idleing before a tune. I'm not worried at all about building a sleeper with a stealth cam or emissions or anything. A lopy idle would be nice. What do you guys think would be a good cam to do this with the 5.3 heads. Keep in mind I'm increasing the intake valve size.

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Marc, I guess I was replying to Teke when you posted. I'll reconsider my intake, but what intakes should I look at. I've got a friend with a Weiand Ligenfelter that I may look at.
I'm pulling the engine anyway. It has 107K on it and I may as well rebuild the bottom end. I don't want to spend stupid money on the bottome end, but I am planning on forged pistons and h-beams. If the crank doesn't need turning I was going to polish it and put new bearings in it and balance it since I want forged pistons.

jmmullin

224R on 112 LSA if you can find one. TSP sells them I know, and are great to deal with. It might not have extreme lope, but it may be hard to find lope with low and mid range power... Mine has a nice idle lope to it but doesn't come to life below 3500 rpm (232/234, .595/.598)

And I too would offer the suggestion to consider a different intake. If you have the money then a FAST 92 with matching throttle body would work very well. A ported one would be even better. Figure in about $1000 to the build if you want that kind of setup and can find it slightly used...

Marc 85Z28

For your goals the LS6 will work better than anything else, perhaps even the FAST intake. Those are the only 2 you should consider.

Have you looked into all the associated costs with rebuilding what you have? By the time you buy the forged pistons and rods, turn/polish the crank and have all the machine work done you could have just bought a ready to run shortblock for literally a couple hundred more.

Again, run as much compression as you can. 11:1 will run fine on 91 octane or better, 11.5:1 will run on 93 octane. Anything over that will require quality 93 octane with proper cam selection and a competent tuner. I'm running 11.7:1 and run 93 octane with no knock retard under WOT, low RPM high load conditions, 100+ degree heat, etc.

Chrome383Z

Don't bother with those POS 5.3 heads. Not worth the money for gaskets/head bolts over 241 heads.

If you want to put as cast heads on a budget 243's are a better head.

jmmullin

^^^ I think he means the stock 5.3 heads that you've got. The CNC ported ones I got were a pretty good deal I think (hope)