2-bolt vs 4-bolt
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Joined: Jul 2004
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From: Rockmart, GA
Car: 1989 Firebird Formula
Engine: Chevy TPI 350
Transmission: A/T 700 R4
2-bolt vs 4-bolt
What is the difference between a 2-bolt main and a 4-bolt main? In general, do most people prefer 4-bolt. Also, did any of the Formula TPI 350 come with 4-bolt?
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Joined: Jan 2002
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From: Valley of the Sun
Car: 82 Z28
Engine: Al LT1 headed LG4 305
Transmission: TH350
Axle/Gears: 3.73 posi with spacer
No 3rd gen L98 350's came with 4bolts, they are all 2-bolts. The only L98 350's that had 4-bolt were the Corvettes. The number of bolts refers to the number of main cap bolt there are. 4-bolts are generally thought to be stronger on all SBC's except the 400. But for anything driven on the street it doesn't really matter and number of bolt will be strong enough.
Joined: Aug 1999
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From: Aurora, ON, Canada
Car: 1989 Iroc-Z
Engine: 5.7L TPI
Transmission: 4 Spd Auto
Alot of people will argue that 4 bolts arent really that much stronger than 2 bolts. Alot of people also run the crap out of their 2 bolts and rev them hard and dont have trouble.
Personally I think the best bet is to get a 2 bolt block and have it machined to accept 4 bolt caps where the two outer bolts go into the block on an angle. These are alot stronger than the standard straight 4 bolt block.
Personally I think the best bet is to get a 2 bolt block and have it machined to accept 4 bolt caps where the two outer bolts go into the block on an angle. These are alot stronger than the standard straight 4 bolt block.
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From: Maine
Car: 89 Formula 350 WS6
Engine: 383 miniram
Transmission: 700R4
i agree that the 2-bolt converted to a 4-bolt splayed setup is ideal, but i disagree that a 2-bolt will hold up to anything on the street. how many times have you heard of someone grenading their block from pushing it too hard. 2-bolts just wont rev as high or hold up if you're pushing serious power.
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Originally posted by cormyr
how many times have you heard of someone grenading their block from pushing it too hard.
how many times have you heard of someone grenading their block from pushing it too hard.
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G92Joe
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