how big of a carb can i go on a 5,3

ghostrider

Daily Driver
May 26, 2014
40
0
6
colonia,nj
hi i just out in a 5.3 in my 80 malibu the cam ia a comp cam 604-610 lift 215-223 dur @ .050 a set of 862 heads i bought fully ported and bigger intake valves , victor jr intake ,full length headers and a turbo 400 with a trans brake 3,50 gear in a 9in also have a nos kit 150-250 shot looking to see how big of a carb i can run its my first ls motor also replaced rod bolts with arp,and good race pan new oil pump and timing chain its a truck motor any help thx
 

Killerdave8813

Dragway Regular
Jan 16, 2008
904
2
18
Cincinnati,Ohio
There's a lot of variables that go into that question, street only? Street/Strip? Strip only/Full Race? There are several CFM calculators on the web if you google carb cfm calculator, based on cubic inches, compression ratio, cam profile, expected rpm and probably transmission type, that being said Chevrolet sent the Z/28 302's and LTI 350's both out the door with a Holley 780 vacuum secondary dual line on them and I've seen pictures of full race under 305 ci 60's Trans Am road race engines with dual Dominators on them, it's all about tailoring the carb(s) to your combination and depending on how you're going to use it, I could see an 850 on a 5.3 race engine but it'd be hard to tune to drive on the street especially with an automatic, that being said I have a Holley 600 on the 350 in my 81 with a 4 spd and 3,50 to 1 gears it runs very well all the way to 7500 rpm, sorry I don't have a definitive answer for you but there's some things to think about anyway, Later, KillerDave
 

t5montecarlo

MalibuRacing Junkie
Oct 21, 2007
4,632
31
48
Lederach, PA
garage-scene.com
A 780 vacuum is a very good choice. In the late 70s, I used the Holley calculator to determine my 1967 440 GTX should use a 650 cfm carburetor. I bought a 4777 double pumper and it was really too small for top gear at high rpm.
 

LS6 Tommy

MalibuRacing Junkie
May 15, 2004
15,847
1
38
North Jersey
A 3310 is a great all around carb, especially with an automatic or in a heavy car. My favorite carb in terms of ease of setup. I had one on my LS6 454 the last time it was on the road.
 

Bar50

Pro Stocker
Jan 31, 2009
1,870
2
38
Tulsa, OK
Screenshot_20200828-065400_Facebook.jpg

This one had a 5.3 with I am pretty sure a 228R Texas Speed Cam, Powerglide, and 4.56 gear. Shift at 7,000 or 7500. 600 cfm double pumper on alcohol (class rules for Stock Block Shootout Claimer series/races). I know, because I bought the car after he pulled the LS to go into another project.
 

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