SS 5.3 ls combo

Henry S · 03-06-2015, 01:02 PM

I was thinking of building a 5.3 LS rated at 305 for a super stock GT combination. It looks like I can use the 243 or 799 heads which I think can have flow numbers better than 300. My question is if this is a good combo to build and is the Throttle body large enough to support over 650 hp. I was thinking of putting it in a Nova for GT/GA at 3400lbs.
Any thoughts would be appreciated.

Henry Sliwinski
5774 SS/HA

Jason · 03-06-2015, 01:59 PM

What RWD car was the 5.3 LS installed in from the factory? And where is the 5.3 listed at 305 horsepower?

Henry S · 03-06-2015, 02:24 PM

I don't think there are any RWD cars but I was looking at the 2007 impala engine. Since aftermarket blocks are allowed could it not be used?

Henry S · 03-06-2015, 02:26 PM

I don't think there are any RWD cars but I was looking at the 2007 impala engine. Since aftermarket blocks are allowed could it not be used? Sorry it is rated at 303 hp.

Troy Henderson · 03-06-2015, 05:55 PM

I've been wondering about this combination..

JRyan · 03-06-2015, 06:41 PM

Don't know about the block situation. But the heads flow great. We've had a couple sets on the bench that we've done flow over 300cfm @.700 without getting really crazy with them with the stock size valves. Could be a pretty interesting combination I think.

Rick

Bryan Broaddus · 03-06-2015, 06:52 PM

Removed

Henry S · 03-06-2015, 06:59 PM

I think the aftermarket block would be my choice on this build. and the heads have great potential. I am just not sure if the throttle body can support the airflow demands. Maybe a sheet metal intake can overcome the throttle body size. I would like to see the motor make between 680 to 700 hp. I think the heads can support that, the question is the other components. I think peak power may be in the 7800- 7900 range.

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.

03-06-2015, 01:02 PM	#1
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	SS 5.3 ls combo I was thinking of building a 5.3 LS rated at 305 for a super stock GT combination. It looks like I can use the 243 or 799 heads which I think can have flow numbers better than 300. My question is if this is a good combo to build and is the Throttle body large enough to support over 650 hp. I was thinking of putting it in a Nova for GT/GA at 3400lbs. Any thoughts would be appreciated. Henry Sliwinski 5774 SS/HA

03-06-2015, 01:59 PM	#2
Jason Member Join Date: Jul 2003 Posts: 235 Likes: 0 Liked 6 Times in 4 Posts	Re: SS 5.3 ls combo What RWD car was the 5.3 LS installed in from the factory? And where is the 5.3 listed at 305 horsepower?

03-06-2015, 02:24 PM	#3
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	Re: SS 5.3 ls combo I don't think there are any RWD cars but I was looking at the 2007 impala engine. Since aftermarket blocks are allowed could it not be used?

03-06-2015, 02:26 PM	#4
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	Re: SS 5.3 ls combo I don't think there are any RWD cars but I was looking at the 2007 impala engine. Since aftermarket blocks are allowed could it not be used? Sorry it is rated at 303 hp.

03-06-2015, 05:55 PM	#5
Troy Henderson Member Join Date: Jul 2006 Location: Kansas City Posts: 404 Likes: 125 Liked 120 Times in 37 Posts	Re: SS 5.3 ls combo I've been wondering about this combination.. __________________ Troy Henderson Henderson Race Shop LLC 816-520-5389 www.hendersonraceshop.com

03-06-2015, 06:41 PM	#6
JRyan Senior Member Join Date: Apr 2003 Location: Aberdeen SD Posts: 645 Likes: 30 Liked 112 Times in 31 Posts	Re: SS 5.3 ls combo Don't know about the block situation. But the heads flow great. We've had a couple sets on the bench that we've done flow over 300cfm @.700 without getting really crazy with them with the stock size valves. Could be a pretty interesting combination I think. Rick

03-06-2015, 06:52 PM	#7
Bryan Broaddus Member Join Date: Jun 2002 Posts: 104 Likes: 2 Liked 18 Times in 4 Posts	Re: SS 5.3 ls combo Removed __________________ Bryan Broaddus 7568 STK ,SS

03-06-2015, 06:59 PM	#8
Henry S Junior Member Join Date: Aug 2007 Posts: 83 Likes: 11 Liked 19 Times in 7 Posts	Re: SS 5.3 ls combo I think the aftermarket block would be my choice on this build. and the heads have great potential. I am just not sure if the throttle body can support the airflow demands. Maybe a sheet metal intake can overcome the throttle body size. I would like to see the motor make between 680 to 700 hp. I think the heads can support that, the question is the other components. I think peak power may be in the 7800- 7900 range.

03-09-2015, 12:38 PM	#9
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,348 Likes: 296 Liked 248 Times in 87 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	#10
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.