Open or Crate?

[88bluestar]

Open engine or Cheated up crate?
Both must use a 2 bbl rochester, and exhaust manifolds(no ram type). Most use the early 90's camaro lt1 manifolds. crate has a 6,200 rpm limit.
Cheated up crate is camshaft ground with different duration, LSA, but retains legal lift.
changes made to oil pump etc to aid in keeping hydraulic lifters from leaking down at higher rpm. Valve springs can be changed up to gain an advantage.

Aluminum pulleys and radiators are permitted.
13.2 Overflow tubes must be directed to the ground, and inside of the frame rails.
13.3 Racecar must have the capability of starting without being pushed or pulled. Must be able to join lineup
on demand and unassisted.
13.4 Aftermarket steel motor mounts in stock location are permitted. Mid mounts are permitted (no mid plate).
13.5 OPTION #1 – Crate Engine:
13.5.1 GM Performance Parts (GPP) factory-sealed CT350 Chevy small block crate engine (Part No. 88958602 or
19258602): includes four-bolt-main block, 9:1 hypereutectic pistons, cast iron crankshaft, GM iron Vortec
cylinder heads, high-rise dual-plane intake manifold, 8-quart single kick-out circle track oil pan, valve
cover kit with breather tube and breather, unique dual-pattern cam and special "kool nut" rocker arm nut
design.
13.5.2 Must utilize one (1) GM two-barrel Rochester carburetor. Spacer between carburetor and intake may be
no more than one-half (0.5) inch total with one-tenth (0.1) inch maximum thick gaskets and may not be
throttle bore adjustable. Aerosol carburetors are not allowed. Carburetors shall be subject to claim, as
outlined in Claim Procedures (Article 16).
13.5.3 Must utilize soft-touch rev control box with a 6,200 RPM limit. This must always be out of reach of the
driver but easily accessible for inspection at any time.
13.5.4 Must have “Crate” sticker on racecar or crate engine is claimable. Any driver running a “Standard” engine
with a “Crate” sticker will be disqualified. Any driver running with a crate motor 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.
13.5.5 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.
13.5.6 GM seal bolt exception is USRA, USMTS or approved rebuild seals (call 515-835-9946 for verification).
13.5.7 Oil pan may be replaced by USRA certified repair center with KEVKO Part No. 1087 NRH (pan) and
KEVKO Part No. 1003-1 3/4 (pick-up). Call KEVKO Oil Pans & Components at 800-770-3557 or visit
kevko.net.
13.5.8 Crate Engine is not subject to claim.
13.6 OPTION #2 – Standard Engine:
13.6.1 Must be stock appearing. Any American make is permitted. Absolutely no changes allowed. Must use
stock firing order for that make and model (GM to GM, Ford to Ford, etc.). Titanium is not allowed.
13.6.2 May be a maximum of 360 cubic inches. (370 c.i. for Chrysler).
13.6.3 Must be a maximum 9.5:1 compression. Exception: 302-, 305-, 307- and 318-cubic-inch engines may run
10.5:1 compression. Only flat top or dished pistons are permitted.
13.6.4 Must appear strictly stock for that model and make and in the original mounts. Parts for 400 cubic inches
or larger are not allowed. Stroke must match block. Block casting number must remain visible.
13.6.5 Only stock appearing crankshafts are permitted. Lightweight cranks are not allowed. No undercut, bull
nosed, gun drilled or knife edge crankshafts allowed.
13.6.6 Lightweight, aluminum and/or fluid dampeners are not allowed
13.6.7 GM five and seven-tenths (5.7) inch or six (6) inch rods are permitted. Must be stock appearing I-beam
non-polished rod. Aluminum or light weight is not allowed. Cap screw rods are permitted
13.6.8 A minimum one (1) inch plug above the oil level in the side of the oil pan is recommended. If not utilizing
a plug, oil pan will have to be removed at time of inspection.
13.6.9 Only stock, unaltered two-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 or #2181 or #2665) or Weiand (#7515 or #8023 or #7516);
Chrysler – Edelbrock (#2176) or Weiand (#7545 or #8022). Porting, polishing or port machining is not
allowed. Bowtie, aftermarket, SVO and W2, marine, VORTEC or other special production intake manifolds
are not allowed. Spacer between carburetor and intake may be no more than one-half (0.5) inch total
with one-tenth (0.1) inch maximum thick gaskets and may not be throttle bore adjustable. External
cooler lines from back of intake to front of intake is not allowed.
13.6.10 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; World Products Part #043600 or #042670; Ford
– World Products Part #53030; Chrysler – EQ Part #CH138B; RHS/Indy Part #20300 or #20301. Heads
may be flat milled to reach the 9.5:1 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.
13.6.11 Screw-in studs, guide plates and poly-locks are permitted.
13.6.12 Roller cams and lifters are not allowed. Roller Rocker arms are not allowed (stock-type stamped steel
rocker arms or cast steel rocker arms only). Roller tip rocker arms are permitted. Chryslers may utilize
OEM steel shaft rockers but may not exceed one hundred twenty (120) pounds of valve spring seat
pressure and must maintain OEM valve spring dimensions. Under valve cover pressurized valve train
oiling systems are not allowed.
13.6.13 Mushroom lifters are not allowed (stock diameter only). Must match make and model.
13.6.14 Stud girdles are not allowed.
13.7 Exhaust System & Mufflers:
13.7.1 Must be cast iron exhaust manifolds. Headers are not allowed. Center dump type manifolds are not
allowed.
13.7.2 Exhaust must extend past the firewall.
13.7.3 Must remain dual exhaust. Crossover or “Y” pipes are not allowed.
13.7.4 Exhaust adaptors between manifold and cylinder head are not allowed

[CamKing]

Do they allow any chassis/tire modifications for the 602 crate? (larger spoiler, less weight, better tire, etc)

[88bluestar]

Same for both. If you run a passenger type tire there is no minimum weight however, that's for either engine option.

[CamKing]

Then I would go with an open engine.

[CamKing]

The open motor can make a lot more HP, then the crate, but where the crate will sometimes out-perform the open engines, is on restarts.
Some tracks will allow the leader to drop the rpm's way down for the restart, and that will give the advantage to the crates.

Since the open engine has to run cast iron exhaust, I wouldn't focus on making a bunch more top-end then the crate, I would focus on making more power everywhere.
The crate is limited to 6,200, so build an engine for 6,400-6,800rpm
Go with limited travel hydr lifters, to increase the bottom-end power.
Go with a hydr cam in the 238/243@.050" range, on a 106-108 LSA, depending on how well you can hook up the tires.

[88bluestar]

On the limited travel hyd lifters, is a high oil pressure oil pump needed. 1.6 rocker work with the cam you noted?

[Tuner]

If you play this restricted carburetor game in an engine modeling computer program the shortest stroke nearly always wins with more HP and the widest HP RPM range. The total indicated HP is a constant limited by airflow but the brake HP increases by reducing friction and internal HP loss with the shortest stroke. However, the way these rules read it probably isn't possible to have high enough compression ratio unless the 76 cc head can be cut to smaller chamber size.

[rickb33x]

Way I gather is that a 350 is 4.000x3.480 stroke crank, up to 360 cid max. Destroked 400’s etc aren’t allowed. My plan is to go 40-60 over to take advantage of the 360 rule. Plan to run a light piston, low tension rings, and anything else to cut friction down but gain torque/hp

[CamKing]

On the limited travel hyd lifters, is a high oil pressure oil pump needed. 1.6 rocker work with the cam you noted?

I recommend a high volume pump, but not required.
Yes, the cam will work with 1.6 rockers

[Walter R. Malik]

Same for both. If you run a passenger type tire there is no minimum weight however, that's for either engine option.

What is the actual weight rule ...?

Pounds per cubic inch or just a minimum weight, no matter what the engine size is...?

[88bluestar]

The American Racer is better grip wise in my opinion so less wheel spin. 360 max on the open engine, I assume max is .030 with crates?

The overall weight of the racecar shall be measured at the conclusion of an event with the driver in the
cockpit, wearing complete racing apparel.
14.2 Any racecar utilizing OEM passenger tires will not have a minimum weight rule. Any racecar utilizing the
American Racer racing tire must be an overall minimum weight of two thousand nine hundred fifty
(2,950) pounds.
14.3 Lead and/or ballast may be added only in the trunk area and/or motor compartment (lead and/or ballast
is not allowed in the cockpit). Of the total rear ballast weight, at least half of that amount must be added
in motor compartment (Example: If 50 pounds are added in the rear, then at least 25 pounds must be
added in the front).
14.4 All lead and/or ballast must be painted white and securely bolted with two (2) one-half (1/2) inch bolts
per fifty (50) pounds of ballast. May not have more than twenty-five (25) pounds mounted on a single
half-inch bolt.


Stock OEM 205, 215, 225/70 or 75 series 14-inch or 15-inch passenger tires are permitted. American
Racer G60-15 KK704 (Short, Tall, X-Tall) racing tires are permitted. Staggering of tires is permitted.
8.3.2 Mud, racing or fancy, exotic, trick gumball tires are not allowed.
8.3.3 Ice and/or snow tires are not allowed.
8.3.4 Grooving and/or siping is permitted.
8.3.5 Sidewall markings must remain visible. Buffing and/or removing compound designations is not allowed.
8.3.6 Softening is not allowed. Solvents of any kind are not allowed. Altering tires with any components or
chemicals which alter the manufacturer’s baseline settings of the tire are not allowed.
8.4 Tire Testing Procedures:
8.4.1 Random GC (gas chromatography) scans may be performed to identify illegal substances. A GC scan
should always be a peak in 19-20 minutes. If there is no peak, the driver will be disqualified. Driver may
protest the GC scan results and request a mass spec test at the cost to the driver (usually around $300).
The mass spec test will reveal exactly what substance was used. The main peak of the tire should never
be in half.
8.4.2 Traces of chemicals and/or excessive quantities of chemicals found to be outside the baseline on any test
shall result in the penalties declared in Section 4.15 of the USRA General, Rules & Procedures, plus an
additional indefinite financial penalty and indefinite length of suspension. This penalty also applies to
driver refusal of a tire test. Refusal of tire test shall be treated the same as an infraction. Official(s) may
inspect any tire on the racecar and/or any tire in possession of the driver in his/her pit area and/or hauler
(in other words, if you have “doped” tires then do not even bring them to the track).
8.4.3 It is strongly recommended that all drivers use only soap and water. Baking tires will not eliminate traces
of illegal substances. The USRA will aggressively test for illegal substances and will levy severe
punishment for infractions relating to tires.

[Walter R. Malik]

The way the rules are written, I would use a smaller engine with more gear as the carb and intake manifold would be the restriction.
The small block Ford 302, (306 when bored), is allowed a single plane intake manifold and a point more compression ratio ...
as well as the much better World Products heads so,
Getting almost 75 pounds less weight off the front end would be my choice. The ability of the chassis should help more than any torque difference at the wheels ... which wouldn't be much, (if any at all), when using more gear.

[F-BIRD'88]

The rules need an addition for a cylinder head with a small chamber to allow the GM 300 cid +/- engines to compete with 10.5:1 cr and flat tops. Say 1 or 2 GM 305 castings and a S/R head with small 58cc chmbers.

[Walter R. Malik]

Weight removal off the front end of the car, (instead of the rear), to get down to minimum weight, will always be more effective for going fast than the addition of a little horsepower, in that type of vehicle.

[88bluestar]

2701 intake, aluminum water pump, pulleys, are just a few of the things I'm going to have on there along with as little front tubing as I can.