454 LSX BUILD HP Estimates
-LSX BLOCK
-4.185" Bore
-4.125" Stroke Callies Crank
-Custom CP pistons with a reverse dome (mirror of ls7 chamber) 13cc dish
-Callies rods
-WCCH exhaust ported ls7 heads
-Jeremy formato ported ls7 intake
-Comp Cam 244/254 .612/.596 lift, 114 lsa.
-11.06:1 SCR
-8.5 DCR
Last edited by adams2003; Oct 4, 2007 at 10:18 PM.
It is generally accepted that it takes 1.3 CFM to make 1.0 Hp....
Therefore, a 454 should make about 606 engine Hp.... Pretty low isnt it. This stuff came out of a book that I have on Chevy engine design.
The 1.3 CFM to make 1.0 Hp is really for Gen 1 engines. So the above math may not hold well for LSx engines, which seem more efficient than Gen 1 engines.
However, the above formula worked out very close for my head/cam/etc LS1 Camaro SS.
BTW: I am contemplating building a LSx 440 motor, and I expect to pull about 500 RWHp @ 6000RPM which would be about 585 Hp @ the flywheel.
Also, it's pretty common knowledge that for most street strip motors, 2.2 hp per cfm is the formula to use. Pro Stockers approach 2.4 hp per cfm, but we're not anywhere in that league.

2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
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Whats your cam specs?
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Also, it's pretty common knowledge that for most street strip motors, 2.2 hp per cfm is the formula to use. Pro Stockers approach 2.4 hp per cfm, but we're not anywhere in that league.

FWIW, NHRA Pro Stocks are 200++ hp above your 2.4 hp/CI. A 1450 hp @ 9500 500 cube PS makes 800 lb-ft (@9500) or 1.60 lb-ft/cube and 2.9 hp/cube!
2.2hp/cube would be just shy of 1000 NA fwhp on a 454. That's a long way from 700 and I think that might be a stretch for LS7 heads with any intake.
If it made that power @ 7500, the BMEP would be about 232psi or 1.59 lb-ft/cubic inch @ power peak rpm. That's also a stretch. To achieve that kind of BMEP, the LS7 headed engine would need to be a lot smaller.
My $.02
Length of the primaries depends on what you are trying to do with them. The intake tract length is going to determine where the intake ramming peaks are (rpm points), and where the troughs (torque holes) are. You could use the primary length to tune to fill in the holes.
Diameter is probably related more to power output. If you get to 700+ fwhp, smaller than 1-7/8 will probably hurt you. Not everyone agrees with that. They are worried about "losing low end torque with big primaries." I suggest if you do them and the valve timing correctly, you will have a net gain over 1-3/4 primaries. Get the parts for 700 fw first, however. Choose headers last.
Length of the primaries depends on what you are trying to do with them. The intake tract length is going to determine where the intake ramming peaks are (rpm points), and where the troughs (torque holes) are. You could use the primary length to tune to fill in the holes.
Diameter is probably related more to power output. If you get to 700+ fwhp, smaller than 1-7/8 will probably hurt you. Not everyone agrees with that. They are worried about "losing low end torque with big primaries." I suggest if you do them and the valve timing correctly, you will have a net gain over 1-3/4 primaries. Get the parts for 700 fw first, however. Choose headers last.
Well i am kinda limited to what i can use because I have a awd silverado ss. But I was talking about primary size. Anything I go with will be custom and probably expensive so im trying to figure out what will be the best route without having to experiment.
We changed the pistons at the last second to up the CR a little. Here's an updated build list.
-LSX BLOCK
-4.185" Bore
-4.125" Stroke Callies Crank
-Custom CP pistons with a reverse dome (mirror of ls7 chamber) 13cc dish
-Callies rods
-WCCH exhaust ported ls7 heads
-Jeremy formato ported ls7 intake
-Comp Cam 244/254 .612/.596 lift, 114 lsa.
-11.06:1 SCR
-8.5 DCR
How bad is it limited for 1 7/8ths? It's been a while since I've gone under the hood of a Silvy (though I'm tossing around a SSS build up similar to yours or gone boosted)



