Help choosing induction for a stock bottom end.
01-17-2007, 10:44 AM
#1
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Join Date: Jan 2005
Posts: 73
Help choosing induction for a stock bottom end.
My bottom end is going to remain stock for now. My block has a "truck" casting number according to mortec.com and it is a 1 piece rear main short block. I have not had the pan off to see if it is a 2 or 4 bolt block (could be either one from the casting number). It is getting 461 camel hump heads. I am trying to decide how long the bottom end would last with a larger cam and a victor jr. style intake or should I stick with my original plans for a RPM airgap intake and a reasonable cam about 224-234 duration at .050? Will a factory crank and rods even hang on over 6500 RPM or should I stop it right there? What about ARP rod studs will that help at all? Will the heads even support a 350ci motor over 6500?
01-20-2007, 04:12 PM
#3
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Join Date: Nov 2005
Location: WI
Posts: 268
from my research those heads will flow 216/137 at .5 lift
Chevy '461 Iron 161/63cc 2.020/1.600" 64cc
large valve, mediocre combustion chamber head, decent compression and flow
truck, odds are it's 2 bolt but chevy was weird with that
but the bottom end will last however long it's gonna last, if your bearings are good and you have good oil pressure, and you changed the oil at 3000 miles for the things entire life, then i'd leave it alone and figure you have until 150-200,000 miles on the motor in a reasonable setup (no making 350+hp thing was made for like 240hp)
"RPM airgap intake and a reasonable cam about 224-234 duration at .050 224-234" is a big cam for stock heads, peaking power between ~5500-6500 rpm, 6000 rpm is about the cutoff for a motor to live a long healthy life,
now here's the other thing, those heads will flow pretty darn good for stock castings better than 882s on the intake side, but gm never made any 350 that was supposed to shift over 6000 rpm and never made a bottom end that would survive that routinely, they just arent balanced good enough,
new bolts and bearings all around, and a new oil pump at the least on the bottom if the thing has any miles on it and you're going to spin 6k,
i'd look at smaller cams and also with more exhaust duration than intake duration since the heads dont flow as high on exhaust as they do intake, i am however a big fan of airgaps, and i'd look to make power lower, your motor will live longer
Chevy '461 Iron 161/63cc 2.020/1.600" 64cc
large valve, mediocre combustion chamber head, decent compression and flow
truck, odds are it's 2 bolt but chevy was weird with that
but the bottom end will last however long it's gonna last, if your bearings are good and you have good oil pressure, and you changed the oil at 3000 miles for the things entire life, then i'd leave it alone and figure you have until 150-200,000 miles on the motor in a reasonable setup (no making 350+hp thing was made for like 240hp)
"RPM airgap intake and a reasonable cam about 224-234 duration at .050 224-234" is a big cam for stock heads, peaking power between ~5500-6500 rpm, 6000 rpm is about the cutoff for a motor to live a long healthy life,
now here's the other thing, those heads will flow pretty darn good for stock castings better than 882s on the intake side, but gm never made any 350 that was supposed to shift over 6000 rpm and never made a bottom end that would survive that routinely, they just arent balanced good enough,
new bolts and bearings all around, and a new oil pump at the least on the bottom if the thing has any miles on it and you're going to spin 6k,
i'd look at smaller cams and also with more exhaust duration than intake duration since the heads dont flow as high on exhaust as they do intake, i am however a big fan of airgaps, and i'd look to make power lower, your motor will live longer
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