This is the first project I am attempting for use in my boat. What I am looking for is feedback on this project. Estimated HP and CR and suggested boost. Any pointers on the best combo for reliability and performance. (I know, some say bigger is better, but it’s not always true ) but since this is going into my boat there aren’t too many gas stations between buoys. What are the pro’s and con’s between the 177 with a single carb vs. the 6-71 with dual carbs? Will the 177 with a 850 be a better choice over the 6-71 with the 650’s?
I started with my 1991 Bravo Mag. 454 4 bolt main block going .030 over for a 489 (maybe .060 for a 496... decisions, decisions!!!). The casting number is 10069286
PARTS 489/496 FORGED ROTATING ASSEMBLY
FORGED STEEL NITRIDED CRANKSHAFT STROKER 4.250"
4340 H-BEAM ROD SET BBC 6.385
KB PREM FORGED PISTON BBC 489 3CC FLAT
AKERLY & CHILDS EXTREME PISTON RING SET 1/16 1/16
3/16 4.310
CLEVITE PERF ROD BEARING, NEW MAIN BEARING SET
Melling M77HV BBC Oil Pump
COMP Cams #2110Big Block Chevy Magnum Timing Set
COMP CAMS XEM 234-244 @ .050 110LC 1 165.00 165.00T
HYD LIFTER SET
PRO-COMP ALUMINUM CYLINDER HEADS
320CC INTAKE RUNNERS, 115CC COMBUSTION CHAMBERS, 2.25 INTAKES
AND 1.880 EXHAUST STAINLESS SWIRL POLISHED VALVES. 1.460 DUAL
VALVE SPRING ASSEMBLY. 1.460" Dual Spring Assembly. Suitable for Mechanical Flat Tappet or Hydraulic Roller Cams up to .650 Lift 140 PSI Closed / 360 PSI @ .500 lift. .400 THICK DECK.
FLOW DATA @ 28" H20
PC3021 .100 .200 .300 .400 .500 .600
INTAKE 74 166 245 308 340 360
EXHAUST 62 118 160 195 229 248
I have a choice of superchargers and carbs. Weiand 177 or 6-71 BDS/GMC BLOWER BIG BLOCK CHEVY with either combination of 2-850 CFM Holley, 2-650 CFM Holley, 1-750 CFM Holley.
I am also planning on the MSD Boost timing master with rev limiter. Anyone use this before that can advise?