K i just bought a block from a local machinist guy and its a Chev 454  (not the tall deck) with 2 bolt mains...i believe the year of the block is between 73 & 85 ...Question...with a 2 bolt main (splayed mains) which i plan on putting in...How much horsepower do you think this end cap set up should hold?..this car will not be raced, It will do big burnouts but pretty much a show car / driver...but i'd like to see at least 500HP or a little more out of this...Should i be concerned about the end cap situation?...and no NOS....all motor.  

great project...

if i may correct you...it would be standard non splayed two bolt main...and for 75% of applications..a 4 bolt block is not needed...

this build( i am proposing) is semi 'poor boy style' by todays standards' with all the Aftermarket parts around,but all the factory stuff does a viable job....it all depends on RPM and your Hp goals and expectations...

machine all required parts to spec and balance assembly.use ARP main studs,rod bolts ,etc.get a windage tray.use a CompCams K kit like a xs274s,xs282s,or even the old 294s solid sticks.they run real good ...remove exhaust rotators if so equipped and use CC's .300 spacer shims.i am assuming a 781 head?use dual plane,air gap style manifold for TQ ala Proff Products or EDDY...match to a 3000 converter min and a 3.73 or even better a 4.10 gear...great weekend car to beat on...  
many ways to go about it...
just my 02

alan