Stage II build was last spring and involved cam, PRC stage 1 heads, and a larger crank pulley to make ~11 psi of boost on my SBE Gen IV 5.3L. The results were a solid 518 hp and laying down a 12.7@109.5 in the quarter at full weight on 31.5 inch factory goodyears. Fast forward to around thanksgiving and it turns out that lifters don't like too much preload (the heads that I thought had 64 cc chambers really had 59 cc chambers from being milled 0.03").

What I thought would be a 2-3 year life span rapidly turned into a 1 year build when I ended up with some piston to valve contact. The truck still drove and acted strong off idle, but had high KR and erratic idle vacuum. When I started digging, I could feel 7 of the 16 lifters were basically solid but luckily none had come apart. The result was valves which had self clearanced pistons crowns...so I pushed up the timeline on stage III:

• New 377 cubic inch Stage 2 LS3 shortblock from Thompson Motorsports with -11 cc Wiseco forged pistons and forged scat rods and ARP bolts
• BTR Stage 2 PD blower cam - 227/242 .614"/.592" 122+6 (other cam actually is still fine, just thought it would be small for the new combo)
• PRC Stage 2.5 243 heads (same heads with new bigger valves and seats shaped)
• 8 rib drive conversion from LC32 and smoothflow pulleys custom making 8 rib 3.1, 2.9, and 2.75 pulleys and a hub adapter for the Roush
• Johnson 2110 lifters
• 5/16 .105 wall (correct length this time) pushrods
• Maintaining the stock flex fuel pump and 56lb injectors for now, going to see which pulley I can use
• Keeping 1 7/8 kooks long tubes, but will likely convert the y pipe to a 4" outlet and custom fab a 4" single exhaust...thinking with a 20" magnaflow

All of this should put me at ~10.5:1 compression and start out making 7-8 psi of boost. Goal is to make 600 RWHP. This truck is genuinely my daily driver, and I have already been carpooling with the wife for about a month, so I am more than eager to get this going. Already have the old engine being held in with only a couple bellhousing bolts, just waiting for a good time to yank it out.

 

Wow. I'm sorry to hear about that but this next stage will be aggressive!!

Did you already order the cam? It's more of a square port cam...

 

Yeah, I called and spoke to Brian about a custom spec and he said that for a big truck and factory stall that he would spec it like he would for a square port car. Either way it has the same split to what I have now, and I love the way it drives. If I don't like it, I'll swap it again.

 

Anyone had any luck buying a 4 inch over the axle pipe from mbrp or anyone else? I think I could use straight 4 inch pipe and flatten it some to replace the 3 inch outlet on my y pipe and run all the way back to the muffler. From there the muffler and an over axle section is all I need. What are people doing?

 

Finally got the engine out of the truck, you can see the valve marks on all 8.




Also got the heads back from being converted to stage 2.5.


Plus I got the PRW water pump and cam from BTR on a cam motion core.

Still waiting on the shortblock, the blower, and the 8 rib setup.

 

Got a picture of the new pulley setup.




And I checked installed height with the new valves, with almost all of them right at 1.76". Will need to see if I can get a thinner shim. While they were apart I reassembled one with light springs so I can check PTV. They will both get new springs so that I don't have to check them for another couple years.

 

The build is looking awesome. Keep up the good work. We are looking forward to seeing the end result.

 

Thanks! I figure I'll see the short block from you late this month or early next.

 

Got the 8 rib drive pulleys today from LC32. They look like very high quality pieces!

 

Pretty stuff!