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5.3 circle track

General engine tech -- Drag Racing to Circle Track

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rickb33x
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5.3 circle track

Post by rickb33x »

So we have the 5.3 engine as an option for two different classes. 2300 lbs B Mod(max 2650 weight), or a stock car class which is 2950 lbs minumum.
I'm looking at the overall cost so having back ups as an economical and from a future aspect as the engines are slowly gaining use in many racing classes. Vacuum is checked as well as well as carbs should it apply.

With that being said, What would you do to maximize the use of the 5.3 if it was the chosen option?
The normal engine rule is listed first to show comparison, then the 5.3 rules.


B MOD Engine specs are as follows:

i. Maximum of 360 cubic inches with a 1% error. Compression of 10.0 or less with no error.
ii. Stock-type stamped rocker arms or stamped steel, roller tip rockers allowed.
iii. Screw-in rocker arm studs are allowed. 3/8-inch studs only with guide plates. No stud girdles of
any kind,
iv. Poly locks are okay.
v. Must have cast iron two-barrel intake. No acid dipping and no pressure porting. The depth of the
plenum will be measured with a deep side of 3.950 inches maximum and short side of 2.030
inches. We expect to see an unmodified runner to the back of the divider, with ribs that stand up
0.150 inch. Caliper will be used to measure bores and depth. Unaltered marine cast iron two-barrel
intake will be allowed with Vortec heads. The Rochester carb may only be used on the OEM two barrel intake manifold. You can be disqualified or asked to race with a different manifold. The
aluminum manifolds allowed are: GM Edelbrock# 2101,2701 or 2716 Weiand# 7547 0r 7547-1
Ford. Edelbrock# 2121, 2171 or 2665 Chrysler. Edelbrock# 2176 Weiand# 7545. These manifolds
may use a 1” adapter.
vi. If intake is found to be illegal, driver will lose all prize money for that night and points for that
season.
vii. Flat tappet cam shafts only. No roller lifters.
viii. Aluminum water pumps and pulleys are allowed.
ix. Aftermarket power steering pumps are allowed.
x. Must have cast iron cylinder heads, original valve angle and location. Valve springs: 1.250-inch
maximum diameter; .195-inch wire, steel retainers, five full coils.
xi. Any distributor type ignition allowed. No crank trigger or magnetos allowed. No timing retard
control allowed. Must use a rev limiter with a 7,000 RPM chip. Chip must be out of reach of driver.
xii. Crank shaft, cam gear and balancer must weigh a minimum of 50 pounds. Must install a 1-inch
pipe plug to inspect crank shaft or remove pan.
xiii. No titanium anywhere.
xiv. Tachometer may be claimed for $300 by promoter and drivers finishing on lead lap.
xv. No tri-y headers.

Rules for the LS 5.3 engine:

a. The engine will be a steel or aluminum block, 5.3 liters, 327 cubic inches. Aluminum blocks must
add 80 pounds centered from block ± 3 inches. All compression rules apply.
b. OEM crankshaft, pistons, heads, 1.7 ratio rocker arms, lifters, cam chain required.
c. The camshaft will be the original cam or may be replaced with the CT525 camshaft only. Camshaft
specs: valve lift, intake and exhaust .525 inches at the valve. Duration: 226 degrees intake, 236
degrees exhaust. Camshaft lobe lift .309 maximum.
d. The intake manifold will be the Holley 300-132 with 1-inch adapter.
e. Holley 4412 with choke horn is permitted. Four-barrel carburetor is permitted. All carb rules apply.
f. Must use the MSD ignition box. Box numbers 6010 or 6012, depending on teeth count of the
reluctor wheel.
g. Aftermarket parts that may be used: pan, water pump, pulleys, headers, oil filter adapter and
valve spring rods.
h. Winters crank flange adapter may be used to convert the bolt pattern to standard drive pattern.

\CARBURETOR
27. Holley 4412 or OEM two-barrel Rochester. Rochester carburetor may only be used on the factory
two-barrel cast-iron manifold. When used on a Chevy manifold, Holley 4412 may not have an
adapter any thicker than one-half inch with thin gaskets. Holley 4412 must retain all factory
castings (no alterations of any kind; Fuel may be metered. If you have a Rochester that has been
modified beyond the specs, you must run our restricted funnel spacer. Spacer is available at Rick’s
Performance and must be run with thin gaskets and no other spacers. No additional spacers
allowed on either type carburetor, or any alteration of any kind to the manifold. Carburetor specs
are as follows:
i. Holley – Venturi: 1.376 maximum; Base plate bore: 1.690 maximum; Booster vertical dimension:
0.430 minimum; Booster legs will show all casting part lines; Booster leg width: 0.260 minimum;
Booster outer dimension: 0.605 minimum; Booster inside dimension: 0.385 maximum; Thickness
of throttle blade and shaft: 0.190 minimum; Holley choke horn must remain.
ii. Rochester – Venturi: 1.376 maximum; Base plate bore: 1.693 maximum; Booster vertical
dimension: none; Booster legs will show all casting part lines; Booster leg width: 0.420 minimum;
Booster outer dimension: 0.584 minimum; Booster inside dimension: none; Thickness of throttle
blade and shaft: 0.190 minimum; Top on Rochester may be modified, air filter stud may be
installed between venturi.
iii. Four-barrel carburetor is permitted if utilizing the LS 5.3 engine.
28. Tracks have the right to swap intake and/or carburetor with any competitor after third main event
win. Tracks will have stock Chevy and stock Vortec-type intake to trade with competitor. Same
with Rochester two-barrel carburetor.
29. Fuel must be pump gas (includes E85). No additives or performance enhancers allowed
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Re: 5.3 circle track

Post by dannobee »

Are you a promoter or competitor?
rustbucket79
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Re: 5.3 circle track

Post by rustbucket79 »

Why would anyone run the old crap? Auto wrecker engines all day long (5.3L) FTW.

Decent pan and class required peripherals to run the engine, why would you spend money on building an engine?
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Re: 5.3 circle track

Post by Walter R. Malik »

What are the LS cylinder head rules...?

ANY O.E.M. 5.3L heads or do they need to be the Truck heads ...?
Last edited by Walter R. Malik on Tue Apr 06, 2021 11:30 pm, edited 1 time in total.
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Re: 5.3 circle track

Post by dannobee »

rustbucket79 wrote: Tue Apr 06, 2021 11:20 pm Why would anyone run the old crap? Auto wrecker engines all day long (5.3L) FTW.

Decent pan and class required peripherals to run the engine, why would you spend money on building an engine?
Bingo! I wouldn't even be picky about the cylinder heads and run the junkyard engine as is and concentrate on learning how to tune the chassis. Put a circle track oil pan on it, check the oil pump pickup o-ring, and go racing! If she blows, put in another junkyard bullet. I would run Tri-Y headers if legal. And the lightest clutch/flywheel combo allowed by the rules. And which 4bbl carb? Is ANYTHING legal?
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Re: 5.3 circle track

Post by rustbucket79 »

Seems to me the rules screw the old engines. I could see if there was a restriction on the LS but you can run the same carb on either. Running 5.3 cores must be a dime a dozen in the US.
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Re: 5.3 circle track

Post by rickb33x »

I'm a competitor.
Only the stock cam, or CT525 cam in rules.
Tri-Y aren't allowed in either class. They also have a muffler mandate to cut down decibals but not real restrictive(tube muffler maybe 8" in length.
the B mod class with a regular race engine must use 2bbl, but a B mod with a 5.3 can use a 4bbl so wouldn't the horsepower gap close up quite a bit?
The stock car rules are a bit different though since they are USRA stock car rules.... They are below.

ARTICLE 7: FUEL SYSTEM
7.1 Fuel:
7.1.1 Automotive gasoline or racing gasoline is permitted. Oxygenated fuel is not allowed; however, an ethanol
blend is allowed up to 85%. Additives of any kind are not allowed. Penalty for illegal fuel is loss of
points, cash and awards earned for that event and subject to a fine.
7.1.2 Cannot be blended with ethers or other oxygenates and may not be blended with aniline or its
derivatives, nitro compounds or other nitro containing compounds. Fuel is tested using a Digitron
dielectric meter. It is the responsibility of the driver and/or owner to have fuel tested.
7.1.3 Upper cylinder lubricants are not allowed.
7.2 Electric fuel pumps are not allowed.
7.3 Carburetor:
7.3.1 One (1) installed carburetor is permitted.
7.3.2 Aftermarket metering block is permitted.
7.3.3 Crate Engine (see Rule 10.9) and 360 Engine (see Rule 13.10) may utilize one (1) Holley 4150 Series
four-barrel carburetor. HP carburetors are permitted. This carburetor has no size requirements but must
remain to function as the 4150 Series carburetor was designed and must utilize Holley type boosters.
Vacuum secondary carburetors are not allowed. Annular discharge boosters are not allowed.
7.3.4 Standard Engine (see Rule 10.11) must use any Holley two-barrel carburetor. Carburetor must utilize a
maximum one and three-quarters (1.75) inch throttle bore. Boosters must remain but no booster or
venturi size is required. Annular discharge boosters are not allowed.
7.3.5 Must be naturally aspirated.
7.3.6 Fuel injection is not allowed. Aerosol carburetors are not allowed.
7.3.7 One (1) standard fuel filter between the fuel cell and the carburetor is permitted.
7.3.8 Cool cans are not allowed.
7.3.9 A one (1) inch adapter plate or spacer is permitted. Distance between bottom of carburetor and top of
intake manifold cannot exceed one and one-quarter (1.25) inch. Spacer thickness must remain the same
front to back and side to side.
7.3.10 Predator carburetors are not allowed.
7.3.11 Carburetors shall be subject to claim, as outlined in Claim Procedures (Article 16).
7.4 Fuel Cell:
7.4.1 Must be commercially manufactured. Boat and/or stock automotive fuel tanks are not allowed

The engines allowed are...
OPTION #1 – Crate Engine
13.9.1 GM Performance Parts (GPP) factory-sealed CT400 Chevy small block crate engine (Part No. 88958604 or
19318604): includes 8-quart circle track oil pan with dual kick-out design, valve cover breather kit, openplenum high-rise intake manifold, 1.5:1-ratio aluminum roller rockers, forged steel crankshaft,
hypereutectic pistons, 23° Fast Burn aluminum heads and special "kool nut" rocker arm design.
13.9.3 Must be unaltered and sealed from factory at appropriate points (intake, head, timing chain cover and oil
pan) with approved GPP break-off bolts. Any altered, damaged or missing GPP break-off bolts will result
in driver being disqualified from that event, loss of all track and national points accumulated up to, and
including, the date of the offense, and a $2,000 fine and fourteen (14) day suspension from all USRAsanctioned events. Second offense carries a $5,000 fine and one (1) year suspension.
13.9.4 May utilize one (1) Holley 4150 Series four-barrel carburetor (see Article 7.3.3). Carburetors shall be
subject to claim, as outlined in Claiming Procedures (Article 16).
13.9.5 Crate Engine is not subject to claim but must have a prominently displayed “Crate” decal affixed near the
A pillar or Crate Engine is claimable. Any driver running a “Standard” engine with a “Crate” decal will be
disqualified. Any driver running with a Crate Engine will not be eligible to claim in that season. Any driver
that claims a Standard Engine and switches to Crate Engine will be eligible to be claimed.
13.10 OPTION #2 – 360 Engine
13.10.1 Must be stock appearing. Absolutely no changes are allowed. Must use stock firing order for that make
and model (GM to GM, Ford to Ford, etc.). Titanium is not allowed.
13.10.2 Must appear strictly stock for that model and make and in the original mounts. Parts for 400 cubic-inch or
larger engines are not allowed. Stroke must match block. Approved aftermarket blocks are permitted.
Approved aftermarket blocks include DART #31161111 or Brodix #BRS400035842 or GM #12480047 or
World Products #084010.
13.10.3 Only stock appearing crankshafts are permitted. Lightweight cranks are not allowed. Undercut, bullnosed, gun-drilled and/or knife edge crankshafts are not allowed. Lightweight, aluminum and/or fluid
dampeners are not allowed. Only flat-top or dished pistons are permitted.
13.10.4 Aluminum or light weight is not allowed.
13.10.5 A minimum one (1) inch plug above the oil level in the side of the oil pan is recommended. If not utilizing
a one (1) inch plug, oil pan may have to be removed at time of inspection.
13.10.6 Absolutely no stroking allowed.
13.10.7 Only stock, unaltered two- or four-barrel low-rise cast-iron intake manifolds or approved aluminum
intakes are permitted. Approved aluminum intakes are: GM – Edelbrock (#2101 or #2701) or Weiand
(#7547 or #7547-1); Ford – Edelbrock (#2121, #2171 or #2665) or Weiand (#7515, #8023 or #7516);
Chrysler – Edelbrock (#2176) or Weiand (#7545 or #8022). Porting, polishing and/or port machining is not allowed. Bowtie, aftermarket, SVO and W2, marine, VORTEC or other special production intake
manifolds are not allowed.
13.10.8 Cast iron stock production or aftermarket steel stock replacement heads are permitted. Porting and/or
polishing is not allowed. GM cars must utilize 76cc heads (approved head numbers are 336, 339, 388,
441, 454, 487, 624, 813, 882, 991 and 993). Aftermarket head numbers are: GM – EQ (Part #CC167ES2
or #CH350I), Dart (Part #10024267 or #10024360) or World Products (Part #043600 or #042670); Ford
– World Products (Part #53030; Chrysler – EQ (Part #CH138B) or RHS/Indy (Part #20300 or #20301).
Chryslers may utilize OEM steel or aluminum shaft rockers but may not exceed one hundred twenty (120)
pounds of valve spring seat pressure and must maintain OEM valve spring dimensions. Heads may be
flat milled to reach the 10.5:1 compression rule. Valve size no larger than 2.02 intake and 1.60 exhaust.
VORTEC heads are not allowed. Beehive valve springs are not allowed.
13.10.9 Roller cams and lifters are not allowed. Roller rocker arms are permitted.
13.10.10 Must be a maximum 10.5:1 compression.
13.10.11 May be a maximum of 360 cubic inches (368 c.i. for Dodge).
13.10.12 GM five and seven-tenths (5.7) inch or six (6) inch rods are permitted. Must be stock-appearing I-beam
non-polished rod.
13.10.14 Cap screw rods are permitted.
13.10.13 Mushroom lifters are not allowed (stock diameter only). Must match make and model.
13.10.15 Stud girdles are not allowed.
13.10.16 May utilize one (1) Holley 4150 Series four-barrel carburetor (see Article 7.3.3). Carburetors shall be
subject to claim, as outlined in Claiming Procedures (Article 19).
13.10.17 Must utilize a maximum 7400 RPM rev-limiter. Rev Limiter may not be within reach of the driver while in
cockpit and must be easily accessible to officials at any time. Any driver caught altering the rev limiter or
ignition system in any way to defeat the rev limiter rule shall receive a 30-day suspension, loss of all track
and national points for the night and a $1,000 fine for the first offense. Second offense shall be a oneyear suspension, loss of all track and national points for the season and a $2,000 fine.
13.10.18 This engine option is not claimable.
13.11 OPTION #3 – Standard Engine
13.11.1 Must be stock appearing. Absolutely no changes are permitted. Must use stock firing order for that make
and model (GM to GM, Ford to Ford, etc.). Aftermarket blocks are permitted. Lightened blocks are not
allowed.
13.11.2 All engines used in competition must be able to be used in conventional passenger cars without
alteration.
13.11.3 Motor mounts may not be removed or altered on engine block. Casting and fittings may not be changed.
13.11.4 Machine work on outside of engine or on front or rear of camshaft is not allowed.
13.11.5 Roller rocker arms are permitted. Roller cams are not allowed. Shaft rocker arms are not allowed.
13.11.6 Aluminum heads and/or blocks are not allowed.
13.11.7 Bowtie or high-rise intakes are not allowed. Only stock, unaltered two- or four-barrel low rise cast iron
intake manifolds or the following aluminum intakes are permitted: GM – Edelbrock (#2101, #2701 or
#2716) and Weiand (#7547 or #7547-1); Ford – Edelbrock (#2121, #2171 or #2665) and Weiand
(#7515, #8023 or #7516); Chrysler – Edelbrock (#2176) or Weiand (#7545). Only unaltered (no porting
and/or polishing) aftermarket aluminum intakes are permitted.
13.11.8 Starter must bolt in stock location.
13.11.9 There is no limit on engine cubic inches.
13.11.10 Engines shall be subject to claim, as outlined in Claim Procedures (Article 16).
13.11.11 Mushroom lifters are not allowed (stock diameter only). Must match make and model.
13.11.12 Stud girdles are permitted.
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Re: 5.3 circle track

Post by dannobee »

Run the 5.3 core, change the cam, call PSI and get some valve springs, put on the circle track oil pan, and go racing. If it blows, take off the oil pan and intake, cam and valve springs and go on to the next one. If they can claim your carb, find a cheap 4150 at least 750cfm and be done with it.

Oh, and depending on how long the main events are and how big the fuel cell is, run the E85, as long is it's REAL E85 and not a blended E50 something. Otherwise, if your mains are long enough that the E85 would require a pit stop, use race gas.
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Re: 5.3 circle track

Post by rickb33x »

E-85 is legal, though I would likely get the E-85 from a source that I know it's the correct blend and not from a regular gas station.
It is a 3/8 mile dirt track so just need to figure out what gearing they are running since we have to run a rev limit of 7,000 rpms.
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Re: 5.3 circle track

Post by 1980RS »

If people think a stock 5.3 out of a 99-05 truck is going to walk away from a SBC 350 Vortec engine, that's a laugher in my book. :lol:
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Re: 5.3 circle track

Post by Krooser »

"no cool can"...that's worth 50 HP right there!!!

Who the hell writes these rules? I did for many years and my rules fit on a single page. WISSOTA has 25 pages before they get to car specs...stoopid.
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Re: 5.3 circle track

Post by rustbucket79 »

1980RS wrote: Wed Apr 07, 2021 8:28 pm If people think a stock 5.3 out of a 99-05 truck is going to walk away from a SBC 350 Vortec engine, that's a laugher in my book. :lol:
Perhaps you missed where the rules state in plain english no Vortec heads allowed. 76 cc heads are legal.
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Re: 5.3 circle track

Post by dannobee »

1980RS wrote: Wed Apr 07, 2021 8:28 pm If people think a stock 5.3 out of a 99-05 truck is going to walk away from a SBC 350 Vortec engine, that's a laugher in my book. :lol:
Like many things in life, you have to read the rules. ANY stock LS head AND a 4bbl carb on the 5.3. SBC gets a 4412 500cfm 2bbl and a cast iron 2bbl intake. And there's a couple of claimer rules in there, too. Go ahead, put $5-10K in a SBC and let someone claim it for $500 after the first race.
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Re: 5.3 circle track

Post by 1980RS »

dannobee wrote: Wed Apr 07, 2021 10:14 pm
1980RS wrote: Wed Apr 07, 2021 8:28 pm If people think a stock 5.3 out of a 99-05 truck is going to walk away from a SBC 350 Vortec engine, that's a laugher in my book. :lol:
Like many things in life, you have to read the rules. ANY stock LS head AND a 4bbl carb on the 5.3. SBC gets a 4412 500cfm 2bbl and a cast iron 2bbl intake. And there's a couple of claimer rules in there, too. Go ahead, put $5-10K in a SBC and let someone claim it for $500 after the first race.
Well that sucks, someone in the sanctioning organization afraid people might go too fast?
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Re: 5.3 circle track

Post by 1980RS »

dannobee wrote: Wed Apr 07, 2021 10:14 pm
1980RS wrote: Wed Apr 07, 2021 8:28 pm If people think a stock 5.3 out of a 99-05 truck is going to walk away from a SBC 350 Vortec engine, that's a laugher in my book. :lol:
Like many things in life, you have to read the rules. ANY stock LS head AND a 4bbl carb on the 5.3. SBC gets a 4412 500cfm 2bbl and a cast iron 2bbl intake. And there's a couple of claimer rules in there, too. Go ahead, put $5-10K in a SBC and let someone claim it for $500 after the first race.
Ya, I have run engines with a 500cfm 2 bbl. Those little 2bbl's work pretty good. Seems like they are trying to get everyone to use the 5.3 over the SBC's and rules are made just so you can figure out how to cheat them.
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