396 vs 406 build up
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Joined: Aug 1999
Posts: 2,441
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From: sweden
Car: GTA -89
Engine: Blown 415"
Transmission: 4L80E
Axle/Gears: Strange 12-bolt
396 vs 406 build up
Time for a new engine. I have some questions.
What exactly is a 396/406, bore/stoke/rods?
5.7 or 6.0 rods what is better?
Other parts is..
- Superram
- JEGS 200 CC heads
- ZZ9 kam
- PROCHARGER
/N.
What exactly is a 396/406, bore/stoke/rods?
5.7 or 6.0 rods what is better?
Other parts is..
- Superram
- JEGS 200 CC heads
- ZZ9 kam
- PROCHARGER
/N.
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Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
A 396 is a .030" over 350 block with a 3.875" stroke aftermarket crank.
A 406 is a stock 400 with a .030" overbore. It is not a separate engine of some type, just a maintained stock one.
Almost any displacement of engine can be built with almost any length of rods, from the stock 400 short ones (5.565") up to 6.125". All you have to do is use the right pistons for the stroke and rod length combo you're building. Needless to say, uncommon combos can run up quite an impressive piston bill, and create other problems as well such as the wrist pin being so high up in the piston that it's up into the ring lands; so even though lots of things are "possible", there are practical limits that depend on your intended usage of the engine.
Better for what? In what way?
A 406 is a stock 400 with a .030" overbore. It is not a separate engine of some type, just a maintained stock one.
Almost any displacement of engine can be built with almost any length of rods, from the stock 400 short ones (5.565") up to 6.125". All you have to do is use the right pistons for the stroke and rod length combo you're building. Needless to say, uncommon combos can run up quite an impressive piston bill, and create other problems as well such as the wrist pin being so high up in the piston that it's up into the ring lands; so even though lots of things are "possible", there are practical limits that depend on your intended usage of the engine.
Better for what? In what way?
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Supreme Member

Joined: Aug 1999
Posts: 2,441
Likes: 1
From: sweden
Car: GTA -89
Engine: Blown 415"
Transmission: 4L80E
Axle/Gears: Strange 12-bolt
Better for my application(boosted).
The engine will not be over 6000 rpm so Should I go for 5.7 or 6.0 rods?
The engine will not be over 6000 rpm so Should I go for 5.7 or 6.0 rods?
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From: SE Michigan
Car: Bright Red 91 GTA
Engine: CARBED LT4
Transmission: MK6
IMO id go with the 406...the 396 SB is a great way to side load the cylinders and cause more rapid engine deteriation..that tenth of an inch +- and 13 cubes over a 383 crank is not worth the risk to me...reguardless of the rod length...Go with the 406 and be done with it
If your going from the ground up, go 406.
You will be happier with the larger bore boosted.
Rule of thumb, if you got two motors with similair cubic inches, pick the motor with the bigger bore and shorter stroke.
You will be happier with the larger bore boosted.
Rule of thumb, if you got two motors with similair cubic inches, pick the motor with the bigger bore and shorter stroke.
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From: Louisville, Ky
Car: 1991 Z28
Engine: 383
Transmission: T-5
Axle/Gears: 3.08 10 Bolt
im looking at a 406 too. thinking about putting an lt1 intake on it with some trick heads and a killer cam. think about 900 bucks is worth the short block. its got keith black flat top pistons on gm 5.7 rods with a 10-10 crank and a 292 comp cam and lifters?
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From: Las Vegas, NV
Car: 1985 Camaro, 2015 Audi A4
Engine: V8
Transmission: 700R4
Originally posted by ede
might want to add that a 396 can be had in a SBC as well as BBC
might want to add that a 396 can be had in a SBC as well as BBC
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