There are a lot of people trying to get big HP out of these motors by going large cubes, boring out to where the sleeves are very thin or putting in long stroker cranks or both. I worry both about reliability and getting a truck motor (makes a ton of torque but HP peak is at low RPM.)

So what about buidling with higher RPM in mind? For example, by rough calculations SDPC's El Toro 440ci LS7 (4.127/4.1 B/S) could put out about 570 ft-lb of torque and 605 hp at 6,200 rpm. Building a 416 (4.068/4.0) to peak at 6,700 rpm would give up about 30 ft-lb torque but have 15 more peak hp.

What would it take to build an engine like that that could live reliably in the upper rpm's, redlining at 7,000?

 

IMHO, Forged L92 stock bore with L92/L76 top end. Hollow stem valves, Patriot Golds, YT Ultra Lights, LS7 lifters, G5X3, and all the usual stuff to finish off

 

if you builder puts together a tight motor... 7k redline shouldnt be a problem....

-.660 lift springs
-Double Roller Chain
-ported pump
-heads that dont back up
-lighter valves may help

-good intake that lives over 6500 without falling on its face.
-Quality set of rings. (your builder can set up the ringland, rings spacing and gaps etc..... for the rpm)

 

The only composite intake that flows well to 7,000rpm+ is the LS7. The LS6/L92 and FAST90 all hit a wall below that even when ported.

The intake is going to be your biggest restriction in the equation. Sheetmetal intakes give up power down low and finally surpass composite intakes when you are at the RPM limit of a hydraulic roller cam (around 7500rpm). Meaning unless you are running a solid roller cam and spinning it to 8500rpm a sheetmetal intake isn't worth it.

I'm planning on spinning my LS7 to 7400rpm on occassion.
Forged LS7 427
WCCH ported LS7 heads/intake
25x/25x .650" 111LSA cam
factory dry sump oiling

 

Thanks for the all the input! Looks like I'm going to go LS7 top end in any case.

 

what is wrong with the GMPP and Victor intakes........ to pull more RPM?? Shorter runners then most?? Cheaper then a sheetmetal..

I have not seen charts with those intakes on L92 or LS7 heads?

 

Several people are spinning these motors with big cubes, 427-454 well past 8k. I have dyno videos of our motor spinning it to 8800.