I would like your guys' suggestions for a motor build. I am in the process of buying a built motor for my RCSB 04 truck and I would like to get over 510rwhp and still be street friendly. Would a LS7 427 with high flow heads (PRC247cc or ported LS7 heads) and a medium cam be enough or would I have to step bigger for the LSX454? And If I do step to the iron LSX454 then I'd probably want more power like 530rwhp.
I am keeping my truck as a sleeper and driving it almost daily but I do not want to have issues with the 4.125 stroke so I was more interested in a 427. Its really hot where I live now and I use the AC whenever I'm driving.
The truck has a T56 and 4.10s so I would think that would help with drivetrain loss

All input is appreciated.
Thank You

 

I have an lsx 427 in my c5. I used 245cc Edelbrock heads and 237/246 cam. I think it will get it done. I haven't dyno'd it, but it sure feels like 550ish to me.

Keep in mind that 'street friendly' is a relative term

I think the easiest way to hit your goals and maintain good street manners is a 10:1 370 with a turbo.

 

Thanks a lot for your reply butI would want it to be NA. How's your cam treating you, is it too rough wheb it idles? My builder suggested a 235/239 so it would help in low rpms. I might step up just a bit bigger in the cam but I am not very knoledgeable so all comments and replies are very appreciated

 

built motor and street matters....cant have your cake and eat it.... but a with a 427 who cares bout ac roll windows down

 

Any particular reasons why you are against forced induction? A mostly stock 5.3 with a turbo or blower will make well over 500 to the wheels. Idle smooth, reliable, and much much much cheaper than a ls7

 

I've been beating the **** outta the 416 in my Vette for years. LME shortblock with LME prepped L92 heads and matched L76 intake. I use a 244/252 cam which at the time was thought to be perfect. But depending on the heads the cam choice would be the critical part of your larger motor build.

 

I see this in his SIG..

"2004 RCSB - LQ4/T56 - 212/214 .558”/.559” 116LSA GT67@10psi - Auburn & 4.10's"


Just need more boost and your well past 520hp..

 

I thought I wanted a very strong NA engine as well and looked into doing so. After comparing the cost of a built LSX427 vs a fully forged stroker (383) with all good parts and turbo build I stayed FI. I can get close to double the horsepower at 50-75% the cost.

 

It is pretty hard to beat the sound of a turbo

 

I would swap out that 67mm for a 76mm on that LQ4 and call it a day. 500hp @ 10psi would be no problem and should drive exactly like stock untill you mash the go fast pedal .