550+ na rwhp 427
08-28-2009, 08:55 AM
#1
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550+ na rwhp 427 wanted to see if u guys think 550+rwhp na is a realistic goal on 93 pump with a set of worked 317s or a set of stock l92s. im going to resleeve my ls6 block so might as well do a 427 but before i spend the cash i want make sure my goals a realistic. I also cant decided to get the 317s i have worked over or go with a set of l92s. thanks in advance for any input
08-28-2009, 09:09 AM
#2
Yes. It comes down to how well your intake/heads flow and how much camshaft you are willing to tolerate. I am building an ls7 427 this winter and I have the l92 heads and intake and would like to save the dollars but I want to get some ls7 heads and the new fast intake.
08-28-2009, 09:40 AM
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well its a road course car that i would like to be able to drive on the street but it is by no means a dd and if can get 550 rwhp na thats good enough for me now i just need to make a choice on using my 317s or l92s since its different intake options.
08-28-2009, 09:45 AM
#4
Are you doing the machine work your self as far as sleeving yor old block? I would thank the price of a 427 short block will come in around the price of re sleeving the ls6. Im no expert tho. 317, fast 102, cam in the mid 230 in duration should net you what you want.
08-28-2009, 10:17 AM
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First off, if you're road racing, aren't you more concerned with your torque curve and where your usable rpm range is? I think you'd be better off concerning yourself with making a bunch of torque and doing it over the largest rpm range you can. You spit out a number of 550 rwhp, and if you're not careful, you'll get a peaky cam that you have to rev past 7 grand to get there.
For that kind of horsepower number, he may need a little more cam than that.
For that kind of horsepower number, he may need a little more cam than that.
08-28-2009, 11:43 AM
#6
Go with the L92 heads and remember you don't have to have a big cam for those heads to perform. I bet a 240° .62x"/248 .62x" on a 114° +4° would get you there. Any plans to go with a single plane intake and 4BBL throttle body?
08-28-2009, 12:14 PM
#7
If you're road racing, I would stick to something in the low 230 range for torque on that 427, but that's just me. HP is just a number. You'd be better off to have less peakl HP and more usable midrange rpm torque. Torque wins races 
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08-28-2009, 02:28 PM
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Here's my setup, and now I'm going with 1-7/8 headers and ported fast 95/95 setup so I should make more I'm guessing.:
Build:
Complete 427" Alum Blocked Darton Sleeved Motor. Approx 650 flywheel horsepower. No problem on 91 octane.
On dynojet 248 made 540 rwhp through unlocked 4l60e. 6-spd car would be MUCH higher.
Car was ran for 3 passes at Famoso Dragstrip about 200 miles ago /w 4l60e auto tranny. Went 10.59 @ 129 in full weight 3700 race weight C5 on a avg day.
Details:
Block completely resleeved and machined by Steve Demirjian @ Race Engine Development using a complete Darton MID sleeve setup (Does more darton sleeves than anyone in the country, THE premier place for all Darton LS sleeves). Cost about $3000 alone to get the bare block ready.
http://www.raceenginedevelopment.com...4927/index.htm
Shortblock:
Block is 4.125" Bore
4.0" Eagle Forged Crankshaft
6.125" Lunati Pro-Mod H-beam Rods
JE Custom Forged Pistons (flat top /w valve reliefs)
Billet Steel Main Caps / ARP Main Studs
Ported LS6 Oil Pump
HexaJust Roller Cloyes Timing Chain
Comp OE Replacement Hyd Roller Lifters
Custom 238/246 camshaft, (pretty mild since it was a daily driverable setup)
Top End:
Total Engine Airflow fully ported 237cc AFR Cylinder Heads
Stainless valves, double extreme springs, approx 70cc
ARP Head Studs
Chromemoly Pushrods
Harland Sharp Roller Rockers
Build:
Complete 427" Alum Blocked Darton Sleeved Motor. Approx 650 flywheel horsepower. No problem on 91 octane.
On dynojet 248 made 540 rwhp through unlocked 4l60e. 6-spd car would be MUCH higher.
Car was ran for 3 passes at Famoso Dragstrip about 200 miles ago /w 4l60e auto tranny. Went 10.59 @ 129 in full weight 3700 race weight C5 on a avg day.
Details:
Block completely resleeved and machined by Steve Demirjian @ Race Engine Development using a complete Darton MID sleeve setup (Does more darton sleeves than anyone in the country, THE premier place for all Darton LS sleeves). Cost about $3000 alone to get the bare block ready.
http://www.raceenginedevelopment.com...4927/index.htm
Shortblock:
Block is 4.125" Bore
4.0" Eagle Forged Crankshaft
6.125" Lunati Pro-Mod H-beam Rods
JE Custom Forged Pistons (flat top /w valve reliefs)
Billet Steel Main Caps / ARP Main Studs
Ported LS6 Oil Pump
HexaJust Roller Cloyes Timing Chain
Comp OE Replacement Hyd Roller Lifters
Custom 238/246 camshaft, (pretty mild since it was a daily driverable setup)
Top End:
Total Engine Airflow fully ported 237cc AFR Cylinder Heads
Stainless valves, double extreme springs, approx 70cc
ARP Head Studs
Chromemoly Pushrods
Harland Sharp Roller Rockers
08-28-2009, 02:34 PM
#10
08-28-2009, 02:38 PM
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seeing some of the results of l92's on some of the 427's on here and for the price of them you can't go wrong. so am i going to be giving you a hand on this one george?lol
08-28-2009, 04:07 PM
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well considering the price i think im just going to build a 383 and shoot for the 450 to 500 rwhp range and i have no problem spinnig something to 7 grand if its make power because thats more rpm to stretch to meaning less shifts around the track but yes torque under the curve is main concern. the 550 number was just a bench mark goal to reach, now the question is what are na 383 cars making to the wheels through a six speed and is 500whp out of reach on pump 93?
