L83 5.3 with 7500rpm build - Suggestions?

[fozzi58]

L83 5.3, Whipple 2.9, LTRs, full exhaust. 118k miles, stock bottom end. Owned since new - well maintained.

Looking to refresh my motor over the winter. I would like to have a 7500rpm redline with a broad power curve. Looking for midrange power for track and AutoX. I'd like to see 550+ to the tire if possible, but high HP numbers not required; can be a byproduct. Having the motor pull hard from 2500-7000 is better. Additionally, with the 4.10's in the rear I am sitting at 2500RPM at 75mph which is a little high for my usual highway driving. Having endurance at 2500-3000rpm is more beneficial for the daily driving portion of the motor build, since I usually set the cruise to 80~85mph

I am trying to stay within a $13,500 budget for the motor parts and labor. I have some additional work that needs to be completed which is separate and falls outside the $13.5 budget. If there are issues with the motor that need to be addressed, I understand that will be additional (e.g. scoring on the crank bearings) This is what I have come up with thus far. Experienced engine builders feel free to make suggestions.

Bottom end:
Pull pan and rotating assembly
Inspect components
Gap rings to 0.024" to 0.026" to accommodate 12 lbs of boost safely
Reinstall factory assemblies
Install a high-pressure/high-volume Melling Oil Pump.
Install an SFI-approved ATI Super Damper configured for the Whipple 2.9L belt drive to stabilize high-RPM crank harmonics.

Valve train upgrade
Install non-AFM lifters (Delphi LS7, equivalent, or tie-bar lifters, fresh guide trays (if LS7 lifters), a new valley cover, and high-quality Multi-Layer Steel (MLS) head gaskets.
Secure cylinder heads using ARP Head Studs instead of factory torque-to-yield bolts.
Stealth/Smooth Idle Supercharger Camshaft with an upgraded fuel lobe (+32% or +38%) and a wide Lobe Separation Angle (e.g., Texas Speed F-117 Stealth, BTR Gen V Stage 1 Supercharger Cam, or equiv).
.660" Dual Valve Spring Kit with titanium retainers, hardened 3/8-inch pushrods, and a micro-polished rocker arm trunnion upgrade kit.
Upgraded timing chain
OEM water pump replacement.

Fuel System Upgrades
Install a remanufactured/new GM LT4 High-Pressure Fuel Pump (HPFP)
Install a matching set of GM LT4 Direct Fuel Injectors.
Install an upgraded low-pressure drop-in dual fuel pump system (e.g., Fore Innovations, Walbro, or equiv).

Misc
Install Smoothboost electronic bypass valve & controller.
Tune accordingly. It was suggested to me by my trans-builder that the shift points should be set to 7150rpm to cover for the delay.

I will be handling the cost to send the blower back to Whipple for maintenance & the additional pulley/install.
I will be handling the cost to ship the Mechman alternator back to get re-pullied to support the 7500rpm.
I will cover the cost for an upgraded throttle body.
I already own HP tuners MPVI3 andECM and TCM are unlocked.

There was talk in several forums of upgrading the crank bolts to ARP as well. Should I also be considering having the rotating assembly balanced? Roller rockers? An oil pan with baffles to prevent oil starvation during cornering? No room in the budget to convert to dry-sump. I don't think I am going to have the budget for a forged rotating assembly either - that's a pipe dream with 2 mortgages and 1 kid still in college. Am I missing anything else?

I like the "uniqueness" of keeping the 5.3.....Or should I skip all this ******** and just get a pulled LT4 out of something and do the low-side fuel upgrades?

 

[pronstar]

I would look into a GM crate L8P, 6.6L, nearly plug and play with 525 hp at the crank, for $9k-ish…then put your blower on that if you want more power.

It won’t give you the rpm but it’ll give you all the power.

L8P Crate Engine 523hp 543lbft

Check out the deal on L8P Crate Engine 523hp 543lbft at GM Performance Motor

www.gmperformancemotor.com

 

[Joseph Garcia]

^^^^^x2^^^^^

IMO, a lot easier and more dependable option, than trying to achieve and maintain a 7500 rpm motor mod.

 

[fozzi58]

@Joseph Garcia @pronstar

I've been considering the crate motor as well but my issue is the short redline. I find myself hitting the rev-limiter in 2nd gear during most AutoX events. Courses are usually short, with lower top speeds so I keep it in 2nd the whole time. With another 1000-1500 rpm, I can finish the "long" stretches without hitting the rev limiter.

Additionally, with the looser converter, I'm only getting 3000 usable RPM range between shifts. Not having paddle shifters makes it even more difficult - trying keep the wheel turned in the corners with one hand and find the stalk to hit the shift up/down button is frustrating and a higher risk.

I'm twisted up between what I want the truck to do vs what my budget will allow for.

Yes, it would be a lot cheaper to buy a 4th gen F-Body for 7 grand and just go racing...but where's the fun in that!

 

[Dantheman1540]

Have you looked at a blower spin calculator? The harder you spin a blower the hotter it will get. Typically people over spin them with a tiny pulley but adding 1,500rpm of power band could do the same. Atomic Fab and Perf used to have a great one, might be worth looking for.

I have had a 7k rpm SBE 6.0 for 5+ years now and it has seen hundreds of 7k shifts and bounced off the limiter at 7k plenty of times. But tbh it kinda scares me and I don’t think I’d ever want to hold it that high for long. Especially if blower temps aren’t in check. I think timing chain is one of the most important things, and I can’t remember what I have I’ll try to look it up but it was the top dog at the time for single chains.

 

[pronstar]

The racetrack / AutoX angle is tough.

A high rpm screamer in a heavy street truck doesn’t sound enjoyable to drive.

Have you considered a small gear change (slightly taller/lower numerically) so you aren’t bumping the limiter in 2nd?