building for torque
#1
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Supreme Member
Joined: Jun 2011
Posts: 2,036
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From: knoxville tn
Car: 86 IROC
Engine: 5.0 TPI
Transmission: 700-R-4
Axle/Gears: 2.73 open
building for torque
so, I have a 89 305 roller block that im wanting to build for a project, and I want as much torque as I can sanely get out of it and it live. I have a MAF style TPI that I want to run.i have a set of "416s" that I want to port.id like to have forged flat tops too BUT my question is what would be the best cam for high torque production?? im gonna balance it maybe but ill have a 5000 rpm limit anyway. will a forged 350 crank fit??
#2
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Joined: Aug 2010
Posts: 193
Likes: 0
From: Kansas City
Car: 1984 TA - 17k orig miles
Engine: 355
Transmission: 700R4
Axle/Gears: 3.44 Dana 44 performance rear
Re: building for torque
Build as much compression as you can, use as long a rod as you can, as flat of a piston as you can, as much head flow as you can get with a small runner and cam it for the lower RPM range and if you're really wanting to go for it - install a 3.75" stroke crank and gain about 20 CI of displacement and a long stroke/small bore will generally make a little more torque.
#3
Joined: Oct 2001
Posts: 11,925
Likes: 931
From: Il
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: building for torque
350 crank is the same as a 30Y crank but is balanced differently.
#4
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Joined: Apr 2013
Posts: 1,353
Likes: 1
From: North Salt Lake
Car: '86 Camaro, '94 Camaro, 3 others
Engine: LG4 ->L29, L32->LR4, L36, LG4, L31
Transmission: 700R-4, T5WC, 4L80E, SM465, 4L60E
Axle/Gears: 3.42, 3.23, WTB/WTT 2.93
Re: building for torque
Build for dynamic compression, not for 12:1 static compression. And stock rods will be fine. HR cams allow short duration with high lift, which does great things for torque. Adding 1.6:1 roller rockers will also do great things for cylinder filling without adding duration.
But if you build for power, you can get the torque back with axle ratio and torque converter, if automatic.
Either way, I'd go with the TFS 175 heads, and a shelf cam doesn't exist for how I'd do it. The XFI 254 has too much exhaust duration and too wide of a lobe separation, for low-RPM torque. Late exhaust openings really help low-end. But having overlap at 0.050" hurts low-end, so be careful.gl
But if you build for power, you can get the torque back with axle ratio and torque converter, if automatic.
Either way, I'd go with the TFS 175 heads, and a shelf cam doesn't exist for how I'd do it. The XFI 254 has too much exhaust duration and too wide of a lobe separation, for low-RPM torque. Late exhaust openings really help low-end. But having overlap at 0.050" hurts low-end, so be careful.gl
#5
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Joined: Dec 2002
Posts: 1,592
Likes: 31
From: IL
Car: 1988 Formula
Engine: 421 Little M block
Transmission: TH400 w/brake
Axle/Gears: 9" 4.30s, Wilwood discs, 28X10.5-15
Re: building for torque
Get a 350 block.
You WILL make MORE torque & HP for less money
Good Luck !
You WILL make MORE torque & HP for less money
Good Luck !
#6
Re: building for torque
torque is the result of three major factors
displacement, cylinder pressure and volumetric efficiency, a TPI intake is designed to maximize efficiency in the 2500rpm-4000rpm power band (depends on cam timing heads,,displacement etc.)
the suggestion to buy a 350-406 short block, build it with a 9.5:1 compression ratio, and match it to a set of TRICK FLOW 175CC heads, so you can use that TPI intake with a cam similar to this, with 1.6:1 ratio rockers on that TPI will produce decent mid range torque, you might want to think of it this way, if a sbc engine makes 1.2 foot lbs of torque per cubic inch of displacement a 307 would produce about 368 ft lbs of torque, but a 383 would produce 460 ft lbs
http://www.cranecams.com/product/car...detail&p=23941
http://forum.grumpysperformance.com/...umetric#p35188
http://forum.grumpysperformance.com/...php?f=52&t=401
displacement, cylinder pressure and volumetric efficiency, a TPI intake is designed to maximize efficiency in the 2500rpm-4000rpm power band (depends on cam timing heads,,displacement etc.)
the suggestion to buy a 350-406 short block, build it with a 9.5:1 compression ratio, and match it to a set of TRICK FLOW 175CC heads, so you can use that TPI intake with a cam similar to this, with 1.6:1 ratio rockers on that TPI will produce decent mid range torque, you might want to think of it this way, if a sbc engine makes 1.2 foot lbs of torque per cubic inch of displacement a 307 would produce about 368 ft lbs of torque, but a 383 would produce 460 ft lbs
http://www.cranecams.com/product/car...detail&p=23941
http://forum.grumpysperformance.com/...umetric#p35188
http://forum.grumpysperformance.com/...php?f=52&t=401
Last edited by grumpyvette; 09-02-2013 at 07:06 PM.
#7
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Joined: Apr 2006
Posts: 4,482
Likes: 9
From: Northern, CA
Car: 1989 Iroc-Z Camaro
Engine: TBI,5.0
Transmission: Automatic 700R4
Axle/Gears: Eaton Posi,3.42,LPW Ultimate Cover
Re: building for torque
Then you can figure out how you're going to plant that to the ground.
That's also a fun part.
I re-built a 10 bolt but I doubt that will work for you.
That's also a fun part.
I re-built a 10 bolt but I doubt that will work for you.
Last edited by Ron U.S.M.C.; 09-05-2013 at 02:51 AM.
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