305 383 swap
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305 383 swap
I'm building a 383, with help of YouTube!, and was wondering if any year sbc 350/305 block will drop right in my 83 z for all the accessories. Thanks guys. If so do you recommend a certain year block to start with.
Joined: Mar 2000
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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
Re: 305 383 swap
No 305 can be made into a 383. Let's get that straight right now.
The accessories are not affected by the year of the block. Heads, yes. Block, no.
'85-older blocks were 2-piece rear main seal, like your '83. About all that affects is your flexplate/flywheel, which may not transfer over anyway depending upon the balance type of the 383 you build.
'86-older were all flat tappet. All '87-newer castings were for roller lifter cams, but not all were machined for roller lifters from the factory. That affects your cam and lifter selections.
'79-earlier blocks had the dipstick on the driver side. About all that affects is getting in the way of your '83 exhaust manifolds. If you're building a 383, the only exhaust type you should be considering is aftermarket headers, and '83 exhaust manifolds choke a 305.
It can be fairly stated that casting and machining quality was pretty poor from the factory until about 1986. 1-piece rear main seals are less prone to leakage. I'd look for an '87-up block with roller lifter provisions machined.
What heads were you planning on using? Most any aftermarket type will support your '83 accessories. Most factory 350 heads will, too, but most factory 350 heads are performance junk. '96-'99 "Vortec" truck heads are a notable exception, but they require a different intake manifold than '95-earlier factory heads (and your '83) - however they will accept your '83 accessories.
Hope that helps.
The accessories are not affected by the year of the block. Heads, yes. Block, no.
'85-older blocks were 2-piece rear main seal, like your '83. About all that affects is your flexplate/flywheel, which may not transfer over anyway depending upon the balance type of the 383 you build.
'86-older were all flat tappet. All '87-newer castings were for roller lifter cams, but not all were machined for roller lifters from the factory. That affects your cam and lifter selections.
'79-earlier blocks had the dipstick on the driver side. About all that affects is getting in the way of your '83 exhaust manifolds. If you're building a 383, the only exhaust type you should be considering is aftermarket headers, and '83 exhaust manifolds choke a 305.
It can be fairly stated that casting and machining quality was pretty poor from the factory until about 1986. 1-piece rear main seals are less prone to leakage. I'd look for an '87-up block with roller lifter provisions machined.
What heads were you planning on using? Most any aftermarket type will support your '83 accessories. Most factory 350 heads will, too, but most factory 350 heads are performance junk. '96-'99 "Vortec" truck heads are a notable exception, but they require a different intake manifold than '95-earlier factory heads (and your '83) - however they will accept your '83 accessories.
Hope that helps.
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Re: 305 383 swap
As five7 told you, if (a) your heads have the bolt holes; and (b) your block or pan supports the dipstick being on the correct side; and (c) you get the right flywheel/flex plate to fit your crank; and (d) your block supports the cam you intend to run; then yes, more or less, a 383 will replace your 305 with a minimum of effort. Any of those things DON'T apply, then, you're looking at anything from a minor momentary inconvenience, to a total deal-breaker.
Is brain surgery hard? (hint: are you a brain surgeon??) Is rocket science complicated? (hint: are you a rocket scientist???) We can't answer that for you. Things that I would consider less than an inconvenience, rather more of a selection of stuff on the shelf, other people would find totally insurmountable. And vice-versa.
The devil, and the deity, are both in the details.
Is brain surgery hard? (hint: are you a brain surgeon??) Is rocket science complicated? (hint: are you a rocket scientist???) We can't answer that for you. Things that I would consider less than an inconvenience, rather more of a selection of stuff on the shelf, other people would find totally insurmountable. And vice-versa.
The devil, and the deity, are both in the details.
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Junior Member
Joined: May 2016
Posts: 20
Likes: 0
Re: 305 383 swap
No 305 can be made into a 383. Let's get that straight right now.
The accessories are not affected by the year of the block. Heads, yes. Block, no.
'85-older blocks were 2-piece rear main seal, like your '83. About all that affects is your flexplate/flywheel, which may not transfer over anyway depending upon the balance type of the 383 you build.
'86-older were all flat tappet. All '87-newer castings were for roller lifter cams, but not all were machined for roller lifters from the factory. That affects your cam and lifter selections.
'79-earlier blocks had the dipstick on the driver side. About all that affects is getting in the way of your '83 exhaust manifolds. If you're building a 383, the only exhaust type you should be considering is aftermarket headers, and '83 exhaust manifolds choke a 305.
It can be fairly stated that casting and machining quality was pretty poor from the factory until about 1986. 1-piece rear main seals are less prone to leakage. I'd look for an '87-up block with roller lifter provisions machined.
What heads were you planning on using? Most any aftermarket type will support your '83 accessories. Most factory 350 heads will, too, but most factory 350 heads are performance junk. '96-'99 "Vortec" truck heads are a notable exception, but they require a different intake manifold than '95-earlier factory heads (and your '83) - however they will accept your '83 accessories.
Hope that helps.
The accessories are not affected by the year of the block. Heads, yes. Block, no.
'85-older blocks were 2-piece rear main seal, like your '83. About all that affects is your flexplate/flywheel, which may not transfer over anyway depending upon the balance type of the 383 you build.
'86-older were all flat tappet. All '87-newer castings were for roller lifter cams, but not all were machined for roller lifters from the factory. That affects your cam and lifter selections.
'79-earlier blocks had the dipstick on the driver side. About all that affects is getting in the way of your '83 exhaust manifolds. If you're building a 383, the only exhaust type you should be considering is aftermarket headers, and '83 exhaust manifolds choke a 305.
It can be fairly stated that casting and machining quality was pretty poor from the factory until about 1986. 1-piece rear main seals are less prone to leakage. I'd look for an '87-up block with roller lifter provisions machined.
What heads were you planning on using? Most any aftermarket type will support your '83 accessories. Most factory 350 heads will, too, but most factory 350 heads are performance junk. '96-'99 "Vortec" truck heads are a notable exception, but they require a different intake manifold than '95-earlier factory heads (and your '83) - however they will accept your '83 accessories.
Hope that helps.
Joined: Sep 2005
Posts: 27,879
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: 305 383 swap
Heads are not part of the block.
For a 83 car, you'd want a 350 from around 80-85 for the most direct "drop-in". However that would guarantee NOT getting a roller block.
Heads must come from 69-95. However that would guarantee NOT getting Vortec ones.
All depends on how much work you're willing to do, i.e. what minor surrounding parts you're willing to replace. None of which really amounts to much; vs how "direct" of a "drop-in" you demand.
IMO the newer the block, the better. However will require more effort / expense / thought / planning.
For a 83 car, you'd want a 350 from around 80-85 for the most direct "drop-in". However that would guarantee NOT getting a roller block.
Heads must come from 69-95. However that would guarantee NOT getting Vortec ones.
All depends on how much work you're willing to do, i.e. what minor surrounding parts you're willing to replace. None of which really amounts to much; vs how "direct" of a "drop-in" you demand.
IMO the newer the block, the better. However will require more effort / expense / thought / planning.
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From: Bowdon, GA.
Car: 1988 Camaro
Engine: 355, 10.34:1, 249/252 @.050", IK200
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Axle/Gears: Ford 9", detroit locker, 3.89 gears
Re: 305 383 swap
The block and accessories are interchangeable.
Only a hand full of things to look out for.
55-67 has short water pump, and no acc. holes in heads
86 up is a 1 pc rear main seal and center bolt valve covers.
90's and 2000's truck acc. brackets are taller and run into clearance probs with third gen hoods.
As far as bolt right up, you can use any 55-2000 sbc gen one block,
Then you can bolt any sbc heads to that block,
Then you can bolt any acc. bracket system to those heads and block that will support it. Meaning you can't run 55-67 heads and expect 68-2000 brackets to fit them.
You must use the correct flexplate/flywheel for your crank (one or two pc. rear main seal)
You must use the correct oil pan and dipstick for block (driver or pass side)
IMHO it is best to start with a 96-00 vortec 350 truck/van/suv engine (block and heads)
Then on that you can add any 68-00 sbc gen 1 acc. brackets
Only a hand full of things to look out for.
55-67 has short water pump, and no acc. holes in heads
86 up is a 1 pc rear main seal and center bolt valve covers.
90's and 2000's truck acc. brackets are taller and run into clearance probs with third gen hoods.
As far as bolt right up, you can use any 55-2000 sbc gen one block,
Then you can bolt any sbc heads to that block,
Then you can bolt any acc. bracket system to those heads and block that will support it. Meaning you can't run 55-67 heads and expect 68-2000 brackets to fit them.
You must use the correct flexplate/flywheel for your crank (one or two pc. rear main seal)
You must use the correct oil pan and dipstick for block (driver or pass side)
IMHO it is best to start with a 96-00 vortec 350 truck/van/suv engine (block and heads)
Then on that you can add any 68-00 sbc gen 1 acc. brackets
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