PRC As Cast 225's with TSP 228/232 LS1 Results 445hp/411tq
 

Modifications:

• PRC As Cast 225 heads with Hollow valves. Standard .660" Dual Valve Spring with Titanium retainer setup. -60cc chambers for a 10.9:1 or so target compression ratio
• GM MLS Head gaskets with ARP Studs
• 228/232 TSP Cam on a 112
• Dorman LS2 Manifold with 90MM LS2 throttle Body
• 85MM Maf, Blackwing intake, air bridge
• XS Power 1-7/8" Longtubes, Catted x-pipe, Corsa Catback
• HP tuners by me
• 93 Octane
• 44LB Trickflow (Accel) injectors (59% duty cycle)
• NGK TR55 spark plugs, MSD Wires
• Summit Bracket Racer Harmonic Balancer
• RST Twin Disc Clutch with Steel Flywheel
• Stock 1999 LS1 Shortblock with 87k on it. After the cam install cranking compression is 220-230 each hole so it is right around 11.0 comp ratio.

Smoothing of zero below. Smoothing of 3 put down 443-444, so it is consistent.

https://cimg0.ibsrv.net/gimg/www.cor...3284d79a8c.jpg
Street tune was 440hp and first pull. 445 was 3rd pull after adding a degree of timing and flattening the AFR. From here I switched from straight VE (with MAF disabled but installed) to a blend of tuning of MAF and VE. Another degree was attempted, minimal or no gain and picked up KR. All pulls in 4th gear.


This is the before: Good gains.
1999 Factory LS1 Longblock with all the bolt on's above except the following:

• 78MM TB
• 36LB GTP Injectors

https://cimg5.ibsrv.net/gimg/www.cor...0e90a9226d.jpg
Same car summer before. Flex Fuel Tune (04 Tahoe PCM) running around E40. Airflow limited, not timing, as it made nearly this on pump gas a month prior on a different dyno. Car went 12.73@110.5 on this setup, 1.93x 60' street tires, 3200DA.




Overall I am pretty happy with the results. Lost nothing down low. Car pulls from idle (825rpm) without needing throttle on the twin disc. Pulls in 6th gear from 1400rpm with using the cruise control.

Welcome to input and questions/comments, just trying to document the journey. Next up is to pin down the starter issues and to put on the Hoosier QTP's and hit the track.

**update** Ended up finding a chipped flywheel tooth, so the drivetrain had to come out. Going in is a TR6060/C6Z diff setup with some other upgrades to help the car be consistent at the track.


***Update November 2019****

https://www.corvetteforum.com/forums...post1600500137

Best 1/4 mile so far 11.3@122, 1.67 60'.
11.2@126, 1.70 60' - testing 50 shot nitrous.


**Update October 2020***

Finally tuned it with the FAST 102 and Hinson Longtubes. 463 N/A

https://cimg7.ibsrv.net/gimg/www.cor...10eb082c61.jpg

Fast versus Dorman (same pull as the 445 but the smoothing was bumped to 3 vs 0.

https://cimg5.ibsrv.net/gimg/www.cor...c8aeeae789.jpg

Turn that bitch to 7k for some mph

Stock rod bolts, no thanks.

Badass results! Makes me wish I had heads. I agree about the 7k. You can definitely carry out that power out to 7k, but I understand you not wanting to do so.

I am pretty sure it will carry the power, but I am more concerned now with getting drivetrain under it so I can hit the track on some bias-ply tires and have fun with what I have. If I end up with a motor failure or this one hangs in a few years on this setup, I'll put together a lower end and spin it up.

thats just a myth, haha. I have a similar setup trying to touch a high 10, but no nitrous on my end. Post results when you get them.

I wonder how much connecting rod bolt failures actually happen out there and can actually be attributed to 7k RPM speeds. I don't know how much of this is true. I know these LS1/LS6 are stout for the most part. I've taken mine plenty of times up to 6700-6800 after my cam build and holds up fine. There are diminished returns and a lot of risk vs reward in spinning past 6800 for my particular setup since both my heads and cam start choking after this, but you can tell from your graph and your mods that your powerband is up there. You've made a super capable machine, congrats! :cool:

stock bottom end ls6 rev limiter at 7800, ls1 has weaker rod bolts, hundreds of 1/8 mile passes at 7500 then raised it to 7800 last year after new lifters, I’ve learned if you do what the “internet” tells you then you’ll just have a slow average car lol

Good feedback on the RPM, thank you all.
I'll keep walking the rpm up as my comfort and trust increases with the rev limit. Knowing the power will carry is very tempting.

Honestly I am concerned with the power level now and not puking everything out of the rear end. I do have transmission/differential bracing and ties to the subframe with a hinson trans mount as well (used spherical rod ends with 1" OD 316L tubing to create bracing). Here are some pics from 2017:

https://cimg5.ibsrv.net/gimg/www.cor...83a42a39a6.jpg
Side view of bracing installed on differential up to transmission
https://cimg0.ibsrv.net/gimg/www.cor...9ff9eea3a2.jpg
Under the car looking forward.
https://cimg5.ibsrv.net/gimg/www.cor...acc9af5265.jpg
Mock up of bracing

Everything inside the casing is stock.

So now the decision is to bolt on the "mini big and skinny" setup and walk it out, or drop the drivetrain and upgrade components. This will require pondering....

The QTP's should absorb some shock. If you had drag radials I would suggest upgrading the diff. Just got easy and see how it likes it and start saving for diff. I built mine last summer and it's fairly easy.

Okd thread I know but can any of yall tell me what gaskets and replacement stuff Ill need when doing a head, cam, intake swap on a 2000 C5 LS1? I am doing PRC 220 heads, Dorman LS2 intake, LS2 TB, 228R TSP Cam, Trunnion upgrade, LS7 lifters, new lifter buckets, new timing chain set, melling high vol oil pump.

What is it about the steam vents and knock sensors that is an issue?

Is it valve cover, head, intake, water pump, and timing cover gaskets only?

Awesome results. What lifters, pushrods, and rockers did you use? Pushrod length? I'm thinking of doing something very similar.

LS7 Lifters, TSP 7.450" 5/16 pushrods. I ended up in/around the .060-.080 preload. The PRC heads are thicker than factory and the LS7 lifters have a different plunger height.

Stock rockers with the CHE upgrade.

Now the car has a 4" intake, straight speed density, and a Mamo ported LS2 throttle body. I've also wrapped my headers. (Also did a TR6060 and C6 Z06 differential with a 12mm torque tube upgrade). I hope to get it back on the rollers in the fall potentially and crack 450 and would love if it hit 460, will see I guess.

With the Dorman Ls2 intake you'll need to squish down your vent tubes. I've routed the knock sensor wires above and below the steam vents, depends upon what you want to service/plan on servicing. It all fits under the dorman. I pulled them off, measured clearance with clay under the dorman, and squished down the steam vents in a vice.

Gaskets:
Valve Cover
Head Gaskets
Head fastening hardware
Water pump gaskets
Timing cover gaskets
Oil pump o ring if replacing
Front Crank Seal
Exhaust gaskets if not reusable (head to manifold/header)
AIR Tube gaskets or RTV.

Solid results, glad to see someone else not throwing a monster cam in it to make a peak number. I'd definitely rev to 7k and probably lean it out a little bit up top. Thatll prolly get you another 5rwhp. Aim for around 12.8 up top.

Thanks!

I may go to 6800 (stock rod bolts). 12.8 AFR it started to drop a bit of power. This was on straight speed density and was working on the MAF tune as well.

Decided that I'll just go SD and ditch the MAF on this application and see what that does and will try different AFR ranges again at that time. Also I had TR55 plugs, going a range colder now as well as they looked very hot.

Nice build! Let her rip to 7K!!!

I set the limiter on my '00 FRC at 7k shifted just shy not a problem. As for the driveline wheel hop is the biggest killer. If you haven't been through the torque tube, I'd go '01+ and make sure all the bearings and couplers are good.

Solid results, my Futral F11 (228/230), TEA Stg 2 5.3 setup was in the same power range.

Good to know. Next time I go back I'll bump it a bit higher and see if the power drops.

I just swapped in a 12mm torque tube and C6Z diff/TR6060 for prep of future mods. Also changed up the long tubes, intake, and throttle body in a quest to see if there is more in it.

So I just ordered the PRC 225 heads w/ the dual .660 springs, hollow stem intake and ss exhaust valves, and I am having them milled for 60cc chambers to get the 11:1 compression ratio. Along w/ the TSP 228R cam, ls7 lifters, upgraded trunnion rockers, long tubes, catless 3" x-pipe, BB Fusion axle back, Dorman LS2, LS2 90mm TB, 85mm MAF housing, Melling HP oil pump, Vararam V2, 48lb injectors, and 10% under drive Power Bond Balancer, we shall see what she does with just having a small difference in LT size (mine are 1 3/4) and the 228/228 as apposed to the 228/232 for yours and the difference in intakes.

Also what length PRs did you end up with?