I bought an lq9 for a good price but one head was cracked between the intake and exhaust valves. Block was full of rust, so it got sent off to the machine shop for an overhaul. Scored some 243’s for $300. After doing some research (keep in mind I’m also just getting into this hobby, so be gentle) I’m still trying to understand what I can get away with as far as ptv clearance. This build is going in my 2wd 99 rcsb Silverado. It’s going to be a daily driver. It’ll never see a drag strip. I’d like to see 400rwhp. What’s a good setup that won’t cause and smooching between valves and pistons? Springs? Cam? Thanks for any advice in advance.

 

you have plenty of clearance, any mild truck cam will get you what your looking for

 

He's right and you don't need a huge cam either because bigger cams means bigger stall and gears. Call TSP or Cam Motion and tell them what your doing and they can find the right cam for you.

 

Building an iron LS1 that will be replacing a 4.8 in a ext cab truck. Using 799 heads with a truck intake and the cam I'm going with is a 216-224 .553/.553 108+3. That with a 2800-3500 stall and 4.10 gears it should pull pretty hard and have a pronounced idle.

 

Now my 370 build is a 12.4:1 motor with 12cc domes, stock rectangular port heads with an LS3 intake and that cam is a 238-246 .633/.633 111+3 LSA.

 

get the heads done, get a good intake manifold, get the rest of your supporting mods squared away. Those will all help you reach that goal, even exceed it. 400whp in a 6.0 is nothing. TSP and thompson motorsports have really inexpensive CnC porting options out there.

i agree on contacting a professional on spec-ing a cam. they should be able to spec something that will work with what you have going on without having to flycut.

 

A lq9 would probably get to 400whp with just bolt ons.

The 243s are a good choice and will give you a compression bump.

Really a ls3 or ls2 cam would probably work best in it. They have gobs of midrange tq which would be perfect for a 2wd truck and they will run to 7k rpm with good valve springs. Either can easily exceed your goal and make tuning a breeze......which is 3/4 the battle in a dd.