Second thoughts on a cam choice.
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
[QUOTE=Gordonm]Definitly go with at least the hot cam with a 400+ ci SB.
That is very small duration numbers for a 405ci motor.
You should be in at least the 230 @ .050 range and .550 lift range[/QUOTE
with Gordon, you need more duration @.050 and more lift...
That is very small duration numbers for a 405ci motor.
You should be in at least the 230 @ .050 range and .550 lift range[/QUOTE
with Gordon, you need more duration @.050 and more lift...
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
[QUOTE=73jst4fun]
But is the difference betweent he two cams worth the price for a new cam?
Not to mention I'm now considering buying new rods and pistons.
Originally Posted by Gordonm
Definitly go with at least the hot cam with a 400+ ci SB.
That is very small duration numbers for a 405ci motor.
You should be in at least the 230 @ .050 range and .550 lift range[/QUOTE
with Gordon, you need more duration @.050 and more lift...
That is very small duration numbers for a 405ci motor.
You should be in at least the 230 @ .050 range and .550 lift range[/QUOTE
with Gordon, you need more duration @.050 and more lift...But is the difference betweent he two cams worth the price for a new cam?
Not to mention I'm now considering buying new rods and pistons.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by Durango_boy
Returning them is not an option. I bought them almost two years ago, and I bought them on Ebay.
Outline for me what pistons I'd need, and the correct rods. Where would the block clearancing be done?
Outline for me what pistons I'd need, and the correct rods. Where would the block clearancing be done?
Last edited by 63mako; Oct 7, 2006 at 06:15 PM.
Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
[QUOTE=Durango_boy]
But is the difference betweent he two cams worth the price for a new cam?
Not to mention I'm now considering buying new rods and pistons.
As others have recommended like 63mako, try and match your components, anyway you look at it it's going to cost you some $$$, get the correct rotating assembly to match your hot cam and save some machine work....save yourself some aggrevation and do it correct the first time...
Originally Posted by 73jst4fun
But is the difference betweent he two cams worth the price for a new cam?
Not to mention I'm now considering buying new rods and pistons.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
'89 350 heads ... probably 76cc. +0.020" bore at 4.145", 3.75" stroke.
6" rod more desirable than 5.7".
Very FEW 6" rod 4.145" piston choices that are budget-minded ... maybe KB 'though I don't much care for KB hypers. 6"/+0.020not offered in SpeedPro hyper.
Many more for 5.7" ... i.e. SP P/N hyper H616CP-20 ... about $180 @ ebay. These use standard 5/64, 5/64, 3/16 ringpak ... if you already have rings then you can probably use what you've got ... otherwise use E243K.
SpeedPro P/N E-243K-20 "plain" moly ringpak ... about $45 @ ebay
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
6" rod more desirable than 5.7".
Very FEW 6" rod 4.145" piston choices that are budget-minded ... maybe KB 'though I don't much care for KB hypers. 6"/+0.020not offered in SpeedPro hyper.
Many more for 5.7" ... i.e. SP P/N hyper H616CP-20 ... about $180 @ ebay. These use standard 5/64, 5/64, 3/16 ringpak ... if you already have rings then you can probably use what you've got ... otherwise use E243K.
SpeedPro P/N E-243K-20 "plain" moly ringpak ... about $45 @ ebay
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Stupid 400 SBC question: I have a forged steel racing crank that is supposed to be set up for 5.7" rods. Do I still need to use 5.7" pistons, or should I use regular 400 pistons? 
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by jackson
'89 350 heads ... probably 76cc. +0.020" bore at 4.145", 3.75" stroke.
6" rod more desirable than 5.7".
Very FEW 6" rod 4.145" piston choices that are budget-minded ... maybe KB 'though I don't much care for KB hypers. 6"/+0.020not offered in SpeedPro hyper.
Many more for 5.7" ... i.e. SP P/N hyper H616CP-20 ... about $180 @ ebay. These use standard 5/64, 5/64, 3/16 ringpak ... if you already have rings then you can probably use what you've got ... otherwise use E243K.
SpeedPro P/N E-243K-20 "plain" moly ringpak ... about $45 @ ebay
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
6" rod more desirable than 5.7".
Very FEW 6" rod 4.145" piston choices that are budget-minded ... maybe KB 'though I don't much care for KB hypers. 6"/+0.020not offered in SpeedPro hyper.
Many more for 5.7" ... i.e. SP P/N hyper H616CP-20 ... about $180 @ ebay. These use standard 5/64, 5/64, 3/16 ringpak ... if you already have rings then you can probably use what you've got ... otherwise use E243K.
SpeedPro P/N E-243K-20 "plain" moly ringpak ... about $45 @ ebay
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
A lot more options on a +.030 piston than a .020 over if you do want to use 6" rods too. Deck the block to 0 deck and use a .040 head gasket for good quench and best compression. That will work good with your Hot cam too. I wouldn't recommend the KB hyper's either. The above items are about $435. Add grinding and balancing the crank, rod bearings and main bearings and that already internally balanced Scat rotating assembly for $1100 isn't too bad of a price to upgrade to a fully forged bottom end with 6" rods. I still think your heads are your weak point but it will run strong and you can always upgrade heads later if your bottom end is built right.
Last edited by 63mako; Oct 7, 2006 at 10:09 PM.
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Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by I'm Batman
Stupid 400 SBC question: I have a forged steel racing crank that is supposed to be set up for 5.7" rods. Do I still need to use 5.7" pistons, or should I use regular 400 pistons?
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by 63mako
5.7 pistons sized to fit your bore, Standard 400 bore is 4.125.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by I'm Batman
I meant 400 pistons made to use with a 5.7 rod vs. 400 pistons set up for the standard 400 rods. My block is .060 over, but it seems stable.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Originally Posted by 63mako
Yes, You need 4.185 bore pistons for 5.7 rods.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Originally Posted by I'm Batman
Thanks! I wasn't sure if the crank supposedly being designed for 5.7 rods would affect the piston end of the system.
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by jackson
SP P/N hyper H616CP-20 ... about $180 @ ebay
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
Scat P/N 2-ICR5700 5.7" capscrewed rods ... about $210 @ ebay.
Depending upon gasket ... H616CP-20 will make about 9.6:1 - 10.1:1 SCR with OE deck & 76cc heads.
Will anyone say this is a good or bad suggestion? I can handle these prices, and they will get me a lot closer to a 6" rod at 5.7" and the comp will get close to 10.0:1.
What would have to be done to the block or crank if I use the above items? Can I do a standard crank grind? Will standard .010 bearings work with the grind and the new rods? Will I have to have the block worked on AGAIN or will it stand as is?
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by Little Mouse
the pistons will work with 5.7 length rods on a 3.75 stroke crank
with a 4.145 bore ( .020 over ) Spend the money to have it all balanced.
with a 4.145 bore ( .020 over ) Spend the money to have it all balanced.
Okay, so reading this, all I need to do is buy some 5.7" rods, and the crank I have and the piston heads I have will work? Will this put the compression over 10.0:1, and will I have to get a different than stock head gasket?
Yes, I plan on having the crank ground down and get oversized bearings. I have never had an assembly balanced...how is this done?
Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Originally Posted by Little Mouse
do you already have the external balance flexplate and ballancer
for the factory external ballance crank.
for the factory external ballance crank.
I was gonna reuse the flexplate, and I bought a new Speed Pro external balancer. Does this change how to balance the thing?
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
chevys original design of the small block with a 3.00 stroke and 5.70
long rod had a rod ratio of 1.90. if I remember right the 400 used a
5.55 long rod. 5.55 rod divided by 3.75 stroke gives you a rod ratio
of 1.48 if you change to a 5.70 rod devided by 3.75 you have a
1.52, almost no change, if you go to a 6.00 rod devided by 3.75
you have a 1.60 rod ratio. my opinion unless the 5.55 factory rods
are really bad rods I would not waste my time or money switching to
a 5.70 rod the difference in rod angle and how much less it would
side load the block is almost nothing. The 6.00 rod would be worth it
on a motor that say you wanted to turn 6,000 rpm or more but it
sounds to me like you want a real low rpm torque engine. Maybe you
should just make sure the big end of the rod is rezized and round and
put quality arp rod bolts in them. If you plan in the future to use a
higher rpm cam and better flowing heads now would be the time to
go to a 6.00 rod.
long rod had a rod ratio of 1.90. if I remember right the 400 used a
5.55 long rod. 5.55 rod divided by 3.75 stroke gives you a rod ratio
of 1.48 if you change to a 5.70 rod devided by 3.75 you have a
1.52, almost no change, if you go to a 6.00 rod devided by 3.75
you have a 1.60 rod ratio. my opinion unless the 5.55 factory rods
are really bad rods I would not waste my time or money switching to
a 5.70 rod the difference in rod angle and how much less it would
side load the block is almost nothing. The 6.00 rod would be worth it
on a motor that say you wanted to turn 6,000 rpm or more but it
sounds to me like you want a real low rpm torque engine. Maybe you
should just make sure the big end of the rod is rezized and round and
put quality arp rod bolts in them. If you plan in the future to use a
higher rpm cam and better flowing heads now would be the time to
go to a 6.00 rod.
Last edited by Little Mouse; Oct 8, 2006 at 03:36 PM.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Originally Posted by Durango_boy
I was gonna reuse the flexplate, and I bought a new Speed Pro external balancer. Does this change how to balance the thing?
balance if you are taking one off a 350 they are internal balance and
wont work. factory 400 cranks are external balanced at both the
balancer and flexplate/flywheel.