*quick!* need 305 heads flow numbers...
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Supreme Member
Joined: Sep 1999
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From: Oakville, Ct
Car: 1991Firebird T/A
Engine: 350
Transmission: Modified Viper t-56
Axle/Gears: dana 44, 3.55
*quick!* need 305 heads flow numbers...
Looking for runner volumes and flow numbers for stock 305 heads, like the ones that cam on the lg4 motors...
Steve
Steve
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From: Alabama
Well, not sure what the stock numbers were, but a guy I know has been porting 305 heads just recently. I think he came out with about 190 cfm at the most on the intake. As for the exhuast, it looks like it's best to leave it alone aside from the valve job; other porting just hurts cfm.
I'm guessing stock was like 160 cfm or so. In other words, find some better heads if you can. Basic 350 heads should flow about 180 to begin with.
Most of the stuff he was doing can't be done without specialized equipment, so you'd have to have a machine shop take care of it. Probably cheaper in the long run to get another set of heads.
I'm guessing stock was like 160 cfm or so. In other words, find some better heads if you can. Basic 350 heads should flow about 180 to begin with.
Most of the stuff he was doing can't be done without specialized equipment, so you'd have to have a machine shop take care of it. Probably cheaper in the long run to get another set of heads.
Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
World Products lists these numbers for their S/R Torquer 305 heads:
.500" lift: Intake 213 cfm / Exhaust 166 cfm
.400" lift: Intake 198 cfm / Exhaust 156 cfm
That's for as-delivered, unported castings, 1.94"/1.50" valves.
The typical improvement from pocket porting, guide smoothing and gasket matching is 10%.
So, where would you want to spend your die grinding time: Increasing stock heads and end up with 85% of the unported flow of aftermarket heads, or on aftermarket heads?
I know economics often dictate your final action, but you can get World heads for about $600 complete and unassembled.
The "specialized" equipment I used on my heads consisted of: two 2-hp air compressors tied together, 31 gallons of tank between them; $13 die grinder from Harbor Freight; $34 Standard Abrasives Deluxe Porting Kit; goggles; hearing muffs; light weight leather gloves; shop light; clean work bench (the "special" part there being the "clean" part
). Oh, valve lapping compound & suction cup, and valve spring compressor.
.500" lift: Intake 213 cfm / Exhaust 166 cfm
.400" lift: Intake 198 cfm / Exhaust 156 cfm
That's for as-delivered, unported castings, 1.94"/1.50" valves.
The typical improvement from pocket porting, guide smoothing and gasket matching is 10%.
So, where would you want to spend your die grinding time: Increasing stock heads and end up with 85% of the unported flow of aftermarket heads, or on aftermarket heads?
I know economics often dictate your final action, but you can get World heads for about $600 complete and unassembled.
The "specialized" equipment I used on my heads consisted of: two 2-hp air compressors tied together, 31 gallons of tank between them; $13 die grinder from Harbor Freight; $34 Standard Abrasives Deluxe Porting Kit; goggles; hearing muffs; light weight leather gloves; shop light; clean work bench (the "special" part there being the "clean" part
). Oh, valve lapping compound & suction cup, and valve spring compressor. Thread Starter
Supreme Member
Joined: Sep 1999
Posts: 1,383
Likes: 0
From: Oakville, Ct
Car: 1991Firebird T/A
Engine: 350
Transmission: Modified Viper t-56
Axle/Gears: dana 44, 3.55
Actually, i needed these number in a friendly arguement against a ford friend of mine. He wanted to know what the stock 305 lg4 heads flowed. I told them they were about the same if not worse than the crappy 302 heads.
Anyways, i wouldn't waste my time with the s/r's either... for cheaper and some extra time i would go with the vortecs, and be able to use them onthe future 350.
The only reason i would port my current set of stock rebuilt heads would be for s&g purposes, and to just eek a little more out of my current setup.
Steve
Anyways, i wouldn't waste my time with the s/r's either... for cheaper and some extra time i would go with the vortecs, and be able to use them onthe future 350.
The only reason i would port my current set of stock rebuilt heads would be for s&g purposes, and to just eek a little more out of my current setup.
Steve
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