Hi, have been reading old peanut port threads here and got inspiration to build one for myself. This engine is going to my boat, Chris craft Stinger 260. I dont if this thread belong here but i do know that this forum has the most knowledge for this kind of build. I am new member here and have many questions to ask. Heads are 360 casting with stock size ferrea stainless valves int: 2.065 exh: 1.725. pocket ported with multi angle seats, intake valve back is rounded not 30 degree.
Flow numbers 28", good port
0.100= 65.5 cfm
0.200= 137.5 cfm
0.300= 206 cfm
0.400= 239.7 cfm
0.500= 256.6 cfm
0.600= 255.1 cfm
-Block, gm 454 4bolt, bored .030 over, line honed, bore notched.
-Crank, gm nodular cast, 039 casting
-Pistons, speed pro l2349F forged. -29.4cc dome
-Rods, scat I-beam with 7/16 bolts
-Rockers, crane gold 1.7
-Valve springs, comp 924-16
-Intake, 2 Options, edelbrock performer rpm 2.0 or performer 2.0.
-Carb, rochester q-jet 750cfm from 454 mercruiser
Time has come to deside what cam to use and where i set my compressio ratio. after unshrouding the valves my combustion chamber is approx 120cc, that puts my compression approx 10.3 to 1. speed pro pistons has plenty of material to shave of if needed. The first question is what is safe maximum dynamic compression ratio to use. I live in europe and our fuel is EURO 98e 5% ethanol.
Cam 1. Isky mega 270/270, .050: 221/221, lift: 0.549/0.549, lobe 108. overlap 54 deg. dynamic comression with my combo 8.34
Cam 2. Lunati street master 275/275, .050: 225/225, lift: 0.560/0.560, lobe 108. overlap 59 deg. dynamic compression with my combo 8.1
When started this build, i was hoping to get 450hp-500hp engine with good low end torque and peak hp in 5100-5300rpm range(cast cranksahft). What you guys think, what kind of numbers i should expect?
Before unshrouding the valves, intake flow was 260cfm @ 0.500 and [email protected]