questions on building new vacuum rule engine

[4bangerhotrod]

I've never had any experience on this type of. Motor. 15lb of vacuum at 1000rpm stock oem heads no vortec. Cast steel crank I beam rods. I'll post my rules below but I guess my questions are what's the best most reliable cast crank an what's the best I beam rods. Also what's the best way to get my vacum, I know I can get a cam made for vacuum rules. But are there any other tips or tricks for making it pull plenty of vacuum but still run good. How does compression, intake, an valve lash effect all this. What will be the best size engine for this considering it will be a oem heads llikely double humps or are there better oem heads, an will be fed by a 4412. It's going in a 2400lb sportmod.

Engine
A. Engine Block-OEM Cast Iron only. Maximum cubic inch limit of 390.
B. Crankshaft-Must have a stock appearing rear crank flange. Balancing OK, No
lightening, knife edging or reducing of the crankshaft circumference.. Must be cast
iron crank, no steel.
C. Harmonic Balancer-Must be of OEM design with rubber mounted dampener ring
(SFI rating recommended)
D. Connecting Rods-Must be of OEM design (IE If stock rod was “I-beam than
Aftermarket must be “I-beam). Rod length is up to engine builder (does not have to be
OEM length). 
Rods may use bolt and nut or cap screws to secure the caps.
E. Pistons- Cast or Forged, Flat top or Dished. No domed or gas ported pistons
allowed.
F. Camshaft-Hydraulic camshaft only. No roller camshafts allowed. Must pull 15
inches of vacuum at 1000 RPM’s. Must have access to vacuum port in manifold. No
4-7 swaps.
G. Cylinder Heads and Valve Train-Must be unaltered approved OEM. All heads
must have been used in a production vehicle. No limited production or special
purpose over the counter only heads allowed. No porting, polishing or unapproved
valve bowl work or other alterations of any kind to heads or intake. 202’s allowed. No
screw in studs. No pin studs. Must use stock diameter valve springs. Stock steel
stamped rocker arms. No beehive springs. No studgirdal. No VORTEC heads.
Polylocks ok.(not a nice word) No canted value (Cleveland style) heads!
H. Exhaust-May use aftermarket headers. Exhaust system must be mounted in such
a way as to direct spent gases away from (not a nice word)(not a nice word)(not a nice word)(not a nice word)pit of vehicle and away from areas of
possible fuel spillage.
 Exhaust header outlets no higher than midline of the body
sides. Officials may require turn downs on the collectors. Dual exhaust only no “Y”
pipes or 180 headers. No oxygen sensors allowed.
I. Intake-Any cast iron or aluminum intake. No porting or enlarging inside of intake or
gasket matching. No Bowtie, VORTEC, SVO or W2, marine or other special
production intake manifolds.
 No intake manifold to cylinder head spacers allowed.
J. Carburetor-2 barrell Holley 4412 only. No grinding or polishing of any kind allowed.
All carburetor components manufactured by Holley. No Aftermarket base plates,
metering blocks or carb bodies allowed. No milling or grinding of throttle shaft
allowed, shaft must stay round. 
The choke and air horn may be removed, this is the
only re-working allowed, must have stock measurements. Carb gauges will be used.
2.
Steel, aluminum or Phenolic adapter plate or spacer allowed. Distance between the
bottom of carburetor and top of intake manifold cannot exceed 1 ¼ inch! Total spacer
height includes gaskets.
K. Fuel Pump-OEM style diaphragm pumps only.
L. Ignition-OEM Stock appearing Distributors only (all components, even coil cover).
Must run stock firing order. No MSD boxes.
M. Cooling System-Cooling system may be modified. Radiator and oil cooler must
not protrude above interior. No electric waterpumps or cooling fans. No sprinkler
systems. 
Any overflow tubes are to be directed to the ground, between frame rails.
N. Starter-All vehicles must have the capability of starting without being pushed or
pulled. Starter must bolt to engine in factory location.

[purestock45]

look into the rhoads lifters,they help with vacuum...cams with 114 or wider lsa helps also...there are so cams easy to find that work well for the class....don't have to spend a lot of money for a special grind cam....

[4bangerhotrod]

Any body else have any tips. How does compression, style of intake or anything else effect vacuum. What all in the motor effects vacuum besides the cam an liters