SS 5.3 ls combo

Mike Taylor 3601 · 03-09-2015, 12:38 PM

If you are talking 300@28'', if throttle body and intake don't cut back air flow, I calculate around 611 HP @ 8759 rpm, this is calculated using superflow's formulas for HP and peak rpm for HP based on airflow and cubic inch.

Mike Taylor 3601

Henry S · 03-10-2015, 10:06 AM

Thanks Mike, I forgot about those calculations. I have used those in the past and I have found that you may have to multiply the horsepower by the volumetric efficiency to get close to real world numbers. The rpm side was usually close. I didn't think with the longer stroke of the 5.3 that it would need to rpm that high.

Dwight Southerland · 03-10-2015, 10:37 AM

Quote:

Originally Posted by Henry S

I didn't think with the longer stroke of the 5.3 that it would need to rpm that high.

You're kidding, right?

Mike Taylor 3601 · 03-11-2015, 09:50 AM

Those formulas make real world numbers on the superflow I use,stock configuration heads using stock valve locations and angles about 99% of time will make within 5 hp of formula.
When you get into raised runners,18 degrees etc, spread ports,big chief style etc. then they make more than calculated.
LS engines I don't have any dyno info on them,don't know if will just make calculation or more.
I always check head on flow bench when I know I will run a engine on dyno,so I know what hp to expect.
as example a small block i had heads went 275 @ 25'' calculates 594 made it made 596.

Mike Taylor 3601

Adger Smith · 03-12-2015, 12:00 AM

Mike,
I have found the LS heads make more power than the formulas for traditional heads. More like RR and spread port heads. I have a fudge factor when doing LS engine models. I believe his concerns with the T-Body air flow are justified, but not as important as with traditional heads. I've never done a carb or injected restricted LS engine. The closest I done to a restricted one is a 5.7 bracket deal with a good 750.

Mike Taylor 3601 · 03-12-2015, 09:36 AM

I thought LS may make a little more than formulas, with their valve angle and location.
I had fudge factor for big chief it was around +9% power over formula.
Mike Taylor 3601

Henry S · 03-12-2015, 09:47 AM

Thanks everyone for the replies. I appreciate the knowledge sharing and helpful insight.

03-09-2015, 12:38 PM	#1
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: SS 5.3 ls combo If you are talking 300@28'', if throttle body and intake don't cut back air flow, I calculate around 611 HP @ 8759 rpm, this is calculated using superflow's formulas for HP and peak rpm for HP based on airflow and cubic inch. Mike Taylor 3601

03-10-2015, 10:06 AM	#2
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	Re: SS 5.3 ls combo Thanks Mike, I forgot about those calculations. I have used those in the past and I have found that you may have to multiply the horsepower by the volumetric efficiency to get close to real world numbers. The rpm side was usually close. I didn't think with the longer stroke of the 5.3 that it would need to rpm that high.

03-11-2015, 09:50 AM	#4
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: SS 5.3 ls combo Those formulas make real world numbers on the superflow I use,stock configuration heads using stock valve locations and angles about 99% of time will make within 5 hp of formula. When you get into raised runners,18 degrees etc, spread ports,big chief style etc. then they make more than calculated. LS engines I don't have any dyno info on them,don't know if will just make calculation or more. I always check head on flow bench when I know I will run a engine on dyno,so I know what hp to expect. as example a small block i had heads went 275 @ 25'' calculates 594 made it made 596. Mike Taylor 3601

03-12-2015, 12:00 AM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: SS 5.3 ls combo Mike, I have found the LS heads make more power than the formulas for traditional heads. More like RR and spread port heads. I have a fudge factor when doing LS engine models. I believe his concerns with the T-Body air flow are justified, but not as important as with traditional heads. I've never done a carb or injected restricted LS engine. The closest I done to a restricted one is a 5.7 bracket deal with a good 750. __________________ Adger Smith (Former SS)

03-12-2015, 09:36 AM	#6
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: SS 5.3 ls combo I thought LS may make a little more than formulas, with their valve angle and location. I had fudge factor for big chief it was around +9% power over formula. Mike Taylor 3601

03-12-2015, 09:47 AM	#7
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	Re: SS 5.3 ls combo Thanks everyone for the replies. I appreciate the knowledge sharing and helpful insight.