5.3 circle track
Posted: Tue Apr 06, 2021 7:16 pm
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
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