383 to t5
Thread Starter
Junior Member
Joined: Feb 2018
Posts: 50
Likes: 0
From: Tampa fl
Car: 90 rs 58chevy
Engine: 383
Transmission: T5
383 to t5
Alright fellow ******s I'm swapping a 383 in the place of my beaten 305 out of my 90 rs I have some trouble figuring out which flywheel would fit on the zz4 383 I've read that maybe the bolt holes wouldn't line up to the crank it's a 1prms I already know that the max clutch disk dia is 10.95 but I can't find one with the correct spline count that will fit so going with the original 10.5 n the bell housing max flywheel is 153 t so what flywheel do I buy to get it to mate correctly
Last edited by Jimbonanmis; Feb 26, 2018 at 07:23 PM.
Joined: Jun 2003
Posts: 5,028
Likes: 78
From: Desert
Car: 1991 Z28 Vert
Engine: 383 single plane efi
Transmission: T-56
Axle/Gears: 8.8 with 3.73s
Re: 383 to t5
I've never worked on a ZZ4 block but everything I've read about them was that they were basically the 4 bolt main blocks that were used in the 2500 series vans and trucks. A regular 1 piece rear main seal flywheel for say a 92 Camaro Z28 should bolt up fine. Are you saying that the normal flywheel will not bolt up?
Thread Starter
Junior Member
Joined: Feb 2018
Posts: 50
Likes: 0
From: Tampa fl
Car: 90 rs 58chevy
Engine: 383
Transmission: T5
Re: 383 to t5
Honest I haven't checked it's pretty Narly I was just going to get a new one the same size just wasn't sure because it's a 383 I thought the crank bolts would be different
Re: 383 to t5
Same thing on 1pc rms engines. 400 SBCs were two piece, but I'd assume your crank is machined for an external balance flywheel. See the difference is the 1pc rear main seal crank doesn't have the counterweight on it, so the seal can slip over the crank. The weight is on the flywheel, so the bolt circle is a different size to keep from bolting the wrong flywheel to the crank. Clear as mud right?
Trending Topics
Joined: Sep 2005
Posts: 27,861
Likes: 2,427
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: 383 to t5
The 86-up flywheel will bolt to the crank.
However, it's an INTERNALLY balanced unit, with the last little bit of INTERNAL weight installed into the flywheel, which makes the flywheel "appear" to the untrained Internet g00b eye to be "unbalanced" aka "external" balance. It is NOT that.
However, depending on what 383 "kit" you have, your setup MAY require an "unbalanced" aka "external balance" flywheel. Which isn't too big of a deal regardless, since about 18 - 20 ½" holes about ½" deep around the edge OPPOSITE where the "external" weight on a 400 crank would be, will fix it right up.
The "unbalance" on a stock 400 crank is around 25 in-oz. Not too hard to work that backwards into hole dia & depth, # of holes, etc. Don't get all wrapped up into carrying it out to too many places to the right of the decimal point.
Measure with micrometer, mark with chalk, cut with axe... the true sign of a newb (remember the song about "here's your sign": don't be the guy that needs a sign)
But the FIRST THING you gotta do, even before any of that, is to determine whether your 383 setup is "internally" balanced (i.e. will use the stock 305/350 flywheel), or is "externally" balanced (will use a flywheel with the stock 400 unbalance), or what.
However, it's an INTERNALLY balanced unit, with the last little bit of INTERNAL weight installed into the flywheel, which makes the flywheel "appear" to the untrained Internet g00b eye to be "unbalanced" aka "external" balance. It is NOT that.
However, depending on what 383 "kit" you have, your setup MAY require an "unbalanced" aka "external balance" flywheel. Which isn't too big of a deal regardless, since about 18 - 20 ½" holes about ½" deep around the edge OPPOSITE where the "external" weight on a 400 crank would be, will fix it right up.
The "unbalance" on a stock 400 crank is around 25 in-oz. Not too hard to work that backwards into hole dia & depth, # of holes, etc. Don't get all wrapped up into carrying it out to too many places to the right of the decimal point.
Measure with micrometer, mark with chalk, cut with axe... the true sign of a newb (remember the song about "here's your sign": don't be the guy that needs a sign)
But the FIRST THING you gotta do, even before any of that, is to determine whether your 383 setup is "internally" balanced (i.e. will use the stock 305/350 flywheel), or is "externally" balanced (will use a flywheel with the stock 400 unbalance), or what.
Thread Starter
Junior Member
Joined: Feb 2018
Posts: 50
Likes: 0
From: Tampa fl
Car: 90 rs 58chevy
Engine: 383
Transmission: T5
Re: 383 to t5
The engine is balanced externally but it had a 168 tooth flex plate before I removed it to place it on the stand
Last edited by Jimbonanmis; Feb 26, 2018 at 09:33 PM.
Thread Starter
Junior Member
Joined: Feb 2018
Posts: 50
Likes: 0
From: Tampa fl
Car: 90 rs 58chevy
Engine: 383
Transmission: T5
Re: 383 to t5
The 86-up flywheel will bolt to the crank.
However, it's an INTERNALLY balanced unit, with the last little bit of INTERNAL weight installed into the flywheel, which makes the flywheel "appear" to the untrained Internet g00b eye to be "unbalanced" aka "external" balance. It is NOT that.
However, depending on what 383 "kit" you have, your setup MAY require an "unbalanced" aka "external balance" flywheel. Which isn't too big of a deal regardless, since about 18 - 20 ½" holes about ½" deep around the edge OPPOSITE where the "external" weight on a 400 crank would be, will fix it right up.
The "unbalance" on a stock 400 crank is around 25 in-oz. Not too hard to work that backwards into hole dia & depth, # of holes, etc. Don't get all wrapped up into carrying it out to too many places to the right of the decimal point.
Measure with micrometer, mark with chalk, cut with axe... the true sign of a newb (remember the song about "here's your sign": don't be the guy that needs a sign)
But the FIRST THING you gotta do, even before any of that, is to determine whether your 383 setup is "internally" balanced (i.e. will use the stock 305/350 flywheel), or is "externally" balanced (will use a flywheel with the stock 400 unbalance), or what.
However, it's an INTERNALLY balanced unit, with the last little bit of INTERNAL weight installed into the flywheel, which makes the flywheel "appear" to the untrained Internet g00b eye to be "unbalanced" aka "external" balance. It is NOT that.
However, depending on what 383 "kit" you have, your setup MAY require an "unbalanced" aka "external balance" flywheel. Which isn't too big of a deal regardless, since about 18 - 20 ½" holes about ½" deep around the edge OPPOSITE where the "external" weight on a 400 crank would be, will fix it right up.
The "unbalance" on a stock 400 crank is around 25 in-oz. Not too hard to work that backwards into hole dia & depth, # of holes, etc. Don't get all wrapped up into carrying it out to too many places to the right of the decimal point.
Measure with micrometer, mark with chalk, cut with axe... the true sign of a newb (remember the song about "here's your sign": don't be the guy that needs a sign)
But the FIRST THING you gotta do, even before any of that, is to determine whether your 383 setup is "internally" balanced (i.e. will use the stock 305/350 flywheel), or is "externally" balanced (will use a flywheel with the stock 400 unbalance), or what.
Thread
Thread Starter
Forum
Replies
Last Post
EnchantedForest
Camaros for Sale
3
Jun 25, 2017 12:03 AM