5.3 ls parts
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Teching In
Joined: Aug 2012
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From: olive branch, ms
5.3 ls parts I have stock 5.3 wanting to wake it up without loosing reliability, I have a stock ls6 cam and ls6 243 heads going in soon also have 90mm tbss intake thinking about putting on but not sure if its too much intake for the ole 5.3 anyone done this or have opinions??
Staging Lane
Joined: Apr 2014
Posts: 50
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Iʻm also interested in this thread being that I have a 5.3 in my Tahoe...Iʻm putting a Compcam 219/235 .607/.621 113lsa in it as well as porting and polishing my stock heads and supporting that with a matching stall... I researched that this will wake up our 5.3ʻs!!! These guys on here were saying that the tbss intake was too much air for our small block...
The Dynos and Track times tend to show that the 5.3L looses when you swap to a TBSS with 90mm TB.
That being said, on a stock 5.3L with 706 or 862 heads they run a smaller 1.89 intake valve Vs. the 2.0 intake valve on the 243/799 heads. With the bore size of 3.780 on the 4.8/5.3 Block, the intake valve is near the cylinder bore. Especially with a 2 inch valve. When the valve is to close the bore the air tends to stall.
IMO, I believe that's 1 of the reasons why you don't see a benefit steeping up to the TBSS intake and 90mm TB.
That being said, on a stock 5.3L with 706 or 862 heads they run a smaller 1.89 intake valve Vs. the 2.0 intake valve on the 243/799 heads. With the bore size of 3.780 on the 4.8/5.3 Block, the intake valve is near the cylinder bore. Especially with a 2 inch valve. When the valve is to close the bore the air tends to stall.
IMO, I believe that's 1 of the reasons why you don't see a benefit steeping up to the TBSS intake and 90mm TB.
Joined: Jul 2007
Posts: 1,503
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From: ELSA, South TEXAS (956) 802-7700
Early 5.3s came with the smaller valves in 862 and 706 heads as mentioned above.
Later 5.3s came with the bigger valve and better flowing 243 and 799 heads, and nnbs intake, same as tbss, with electronic 87mm tbs...
so 5.3s can work well with with the better flowing heads and intake...
Important, however, to note, is that 862 and 706 heads came with 61ccs...and...243 and 799 heads came with 65ccs.
So if you have an older 5.3 and swap to 243 or 799 heads and nnbs intake, you will have better flowing heads and intake...but...offset and lose power because with 65 ccs, you will lose compression.
So if you want to optimize swap, youll need to mill 243 or 799 heads .030 to lower ccs from 65 to 59 and slightly improve compression improving power in conjunction with nnbs intake.
That is the key right there. Some folks look at the better flow of the head swap without regard to fact theyre losing compression and power, and have a mismatched combo.
Later 5.3s came with the bigger valve and better flowing 243 and 799 heads, and nnbs intake, same as tbss, with electronic 87mm tbs...
so 5.3s can work well with with the better flowing heads and intake...
Important, however, to note, is that 862 and 706 heads came with 61ccs...and...243 and 799 heads came with 65ccs.
So if you have an older 5.3 and swap to 243 or 799 heads and nnbs intake, you will have better flowing heads and intake...but...offset and lose power because with 65 ccs, you will lose compression.
So if you want to optimize swap, youll need to mill 243 or 799 heads .030 to lower ccs from 65 to 59 and slightly improve compression improving power in conjunction with nnbs intake.
That is the key right there. Some folks look at the better flow of the head swap without regard to fact theyre losing compression and power, and have a mismatched combo.
Launching!
Joined: Nov 2010
Posts: 231
Likes: 1
new the new style intake and 87mm tb is superior to the older style.
you didn't say what year truck your working with. the 243/799 should
be milled .030 to bring up the comp.or use the 4.8 pistons. a good
cam will really wake up that 5.3 LT headers are a must for power
you didn't say what year truck your working with. the 243/799 should
be milled .030 to bring up the comp.or use the 4.8 pistons. a good
cam will really wake up that 5.3 LT headers are a must for power
Teching In
Joined: Nov 2013
Posts: 24
Likes: 0
im building a 2008 Ly5 5.3 right now. It came with a set of 243's and i had a cam ground from Cunningham Motorsports. im topping it off with a edelbrock dual plane with a 750 double pumper. i need to get valve springs springs,,,,,, but havent decided. Everything i have now,
-243s,
-7.4'' hardened Push rods
-Comp cams 227*/234* - .613/.576 @ 110*
-Edelbrock perfromer dual plane
-MSD box for ignition
-DOD delete,,,,,
-built 4L60 (need 3400-3600 stall)
hoping for 400hp? more?? we will see. Maybe i should mill the heads?
-243s,
-7.4'' hardened Push rods
-Comp cams 227*/234* - .613/.576 @ 110*
-Edelbrock perfromer dual plane
-MSD box for ignition
-DOD delete,,,,,
-built 4L60 (need 3400-3600 stall)
hoping for 400hp? more?? we will see. Maybe i should mill the heads?
