Go Back   Corvette Forum > C3 Corvettes, 1968 - 1982 > C3 Tech/Performance
Sign in using an external account
Register Forgot Password?
Register Albums Search Today's Posts Mark Forums Read FAQ
Search
C3 Tech/Performance
V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette Sponsored by
VBP

Welcome to Corvetteforum.com!
Welcome to Corvetteforum.com.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join Corvetteforum.com today!


Corvette Store
 
 
C6 Parts & Accessories
C5 Parts & Accessories
Wheels & Tires
Sponsored Ads
 
 
Vendor Directory
  
Reply
 
 
 
 
Thread Tools Search this Thread
Old 04-09-2007, 01:56 PM   #1
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default Big Block 454 Cylinder Head Question.

I'm planning my 454 build, and was looking for some heads. Consider the starting point a stock rebuilt Gen6 454 long block. Stock crank, rods, and pistons. Stock deck, and a yet undetermined cam.

I'm looking into older generation heads, and was wondering what a good chamber CC to shoot for was. 118 seems very common, both in oval and small ports, but also seems a bit high.

What chamber CC should I be looking for?
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 02:13 PM   #2
Bullshark
CF Senior Member
CI 5 & 8 Veteran
 
Bullshark's Avatar
 
Member Since: Nov 2003
Location: St. Charles Mo
Default

Quote:
Originally Posted by Durango_boy View Post
What chamber CC should I be looking for?
Durango, my old iron heads (390hp oval) on the 69 427 and 70 454 were around 100cc for what it's worth.

Why are you going with the old tech heads anyway??

Bullshark
Bullshark is offline   Reply With Quote
Old 04-09-2007, 02:18 PM   #3
brngrhd
CF Senior Member
 
brngrhd's Avatar
 
Member Since: Apr 2007
Location: Dane Wisconsin
Send a message via AIM to brngrhd Send a message via MSN to brngrhd Send a message via Yahoo to brngrhd
Default

loking at head the 100cc chamber heads are called "high compression heads" the 110 heads are the "normal" heads for most aftermarket heads 118-120 sounds normal. imo the old heads work well unless your looking for huge numbers. talking to a bunch or engine builder friends of mine they told me that the stock heads that are on the 69 396 camaro engine that is in my car, would be fine for my 500+ hp build, so why spend 1500 on a new set of iron eagle or merlin heads.
brngrhd is offline   Reply With Quote
Old 04-09-2007, 02:22 PM   #4
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Bullshark View Post
Durango, my old iron heads (390hp oval) on the 69 427 and 70 454 were around 100cc for what it's worth.

Why are you going with the old tech heads anyway??

Bullshark

Well, I was told the heads, 118 CC, on the Gen6 blocks are designed for torque and fuel economy and won't fit the bill very well for a Corvette engine.

The old tech heads are just an option for cheap used heads. I don't mind using Gen6 heads but I want something that'll flow well and not blow my SCR out the window.

So if I use 118 CC heads, I could deck the block, use a thin head gasket, and port if needed for better flow?

Last edited by Durango_Boy; 04-09-2007 at 02:25 PM.
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 02:29 PM   #5
iree75
CF Senior Member
 
iree75's Avatar
 
Member Since: Dec 2002
Location: Leander TX
Default

Quote:
Originally Posted by Bullshark View Post
Durango, my old iron heads (390hp oval) on the 69 427 and 70 454 were around 100cc for what it's worth.

Why are you going with the old tech heads anyway??

Bullshark
My ol' 9840 square ports are at 107cc closed chamber. They came with the motor I bought. But plan on replacing them with AFR 305s in a year or so. Save some weight, better flow and allow someone to have some 9840s that really needs them for their restoration. Check out Engine Masters for some ideas.. http://www.popularhotrodding.com/enginemasters/

Last edited by iree75; 04-09-2007 at 02:32 PM.
iree75 is offline   Reply With Quote
Old 04-09-2007, 02:38 PM   #6
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

The 101cc 69/70 heads used on 390hp engines had a bathtub style
chamber the wall of the chamber was steep and kept the valves
shrouded pretty bad, the 118/119 heads are open chamber the
steep wall is leighed down angled away from the valves helps
unshruod the valves allowing the engine to pull air around the valve
easier. open chamber is the head to have for best overall breathing.
but if you want much compression with 118/119 open chamber you
will need a piston with at least a small dome.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 02:39 PM   #7
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Little Mouse View Post
The 101cc 69/70 heads used on 390hp engines had a bathtub style
chamber the wall of the chamber was steep and kept the valves
shrouded pretty bad, the 118/119 heads are open chamber the
steep wall is leighed down angled away from the valves helps
unshruod the valves allowing the engine to pull air around the valve
easier. open chamber is the head to have for best overall breathing.
but if you want much compression with 118/119 open chamber you
will need a piston with at least a small dome.

Right, and I wanted to stay with stock pistons for budget reasons. I'm trying to build a good budget motor, changing the heads and cam. Will decking help achieve a decent SCR?
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 02:45 PM   #8
Jughead
Senior Member since 1492
St. Jude Donor '09
Support Corvetteforum!

 
Jughead's Avatar
 
Member Since: Aug 2000
Location: 1.Just because I'm paranoid doesn't mean people aren't out to get me... 2.That which does not kill me will probably hurt like hell. 3. Islam is the enemy.
Send a message via AIM to Jughead
Default

Quote:
Originally Posted by Durango_boy View Post
Right, and I wanted to stay with stock pistons for budget reasons. I'm trying to build a good budget motor, changing the heads and cam. Will decking help achieve a decent SCR?
Depends on whether your stock pistons are domed (probably not), dished, eyebrow or flat tops. I used 110cc chambered aluminums and use domed 1971 LS-6 TRW pistons, 14cc volume and ended up with about a 9.4 CR.
__________________

1970 454- M-22 W/Hurst Comp+ 4 speed, Sidepipes, Mellings, Clevite 77, GMPP Al heads, Manley, Moroso, NO cup holders &

Not Correctly Restored Stingray................
When "Cool" was Measured in Cubic Inches!~Nuthin' Like the Sound of a Solid Lifter BB.
....
Jughead is offline   Reply With Quote
Old 04-09-2007, 02:47 PM   #9
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

DB the chamber on an open chamber head is so big decking the block
will do next to nothing to help you. think about it a small block
starts out with only 64cc chambers and the low comp engines had
only 76cc, open chamber factory big block 119.

Last edited by Little Mouse; 04-09-2007 at 02:50 PM.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 02:49 PM   #10
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Little Mouse View Post
DB the chamber on an open chamber head is so big decking the block
will do next to nothing to help you. think about it a small block
starts out with only 64cc chambers and the comp engines had
only 74cc, open chamber factory big block 119.

Okay. So to use 118 CC chamber heads I pretty much have to get small domed pistons.

What would the CSR be with these heads, and stock possibly flat pistons?
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 02:54 PM   #11
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

If your piston is a flat top you might find a way to squeak out a true 8.25/8.5
comp. with a 119 chamber.

Jughead showed you, he has smaller 110 chambers and a 14cc
domed piston and has 9.4 comp. with you using 119 chambers
and if you do happen to have flat top pistons you will be lucky
to have a true 8.25 comp. this is a change pistons for comp.
deal or do without comp. deal.

Last edited by Little Mouse; 04-09-2007 at 03:08 PM.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 03:15 PM   #12
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Little Mouse View Post
If your piston is a flat top you might find a way to squeak out a true 8.25/8.5
comp. with a 119 chamber.

Jughead showed you, he has smaller 110 chambers and a 14cc
domed piston and has 9.4 comp. with you using 119 chambers
and if you do happen to have flat top pistons you will be lucky
to have a true 8.25 comp. this is a change pistons for comp.
deal or do without comp. deal.

What CC dome pistons would be best with a 118?
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 03:16 PM   #13
Bullshark
CF Senior Member
CI 5 & 8 Veteran
 
Bullshark's Avatar
 
Member Since: Nov 2003
Location: St. Charles Mo
Default

Durango, back in my hell bent for leather days, my brother and I rebuilt the 390hp engines for more power. It was sort of a sybling rivalry thing I guess. We each had the stock head chambers machined between the valves to provide clearence for some high dome TRW pistons. Can't remember their part no, but they are still in the 69 today. If our calculations were correct back then, that resulted in ~12-1 CR. We had a pretty radical cam.....the old Crane Fireball. Back in the days when we could still buy the high octane Sunoco they were king of the hill...... at least the hill we lived on After teh gas went south in the early 70's it was a constant battle trying to find AV gas and keep them from rattling the tops out of the pistons. I finally tore the 454 down and replaced the pistons with a set with a lower dome. It calculated out to be around 9.6-1. The engine is sitting on a stand having never been started. That's when I started my second childhood and opted for the RamJet. Fuel Injection helped alot with preignition on the 69 but I still have to be real carefull and run high octane. Needless to say it doesn't get much use.

Bullshark
Bullshark is offline   Reply With Quote
Old 04-09-2007, 03:19 PM   #14
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

No mistake here, I want to use pump gas, and I think a 10.0 comp is what I'll want to shoot for.

I'm not a high RPM kind of driver. I like tooling around at lower RPMs, using the torque more the high RPM HP. I will have a 5-speed manual behind it, and it won't see much if any racing.
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 03:28 PM   #15
L88Plus
CF Senior Member
 
Member Since: Aug 2004
Location: Lubbock TX
Default

I've only seen 4 types of Gen 6 heads. First is the L-29 Vortec head, great exhaust but intake is lacking. 100cc chamber, great compression ratio and good for torque. Second is peanut ports, can't remember the casting number off the top of my head, good for trucks and doorstops. Third is good ol' rectangular port heads. Very similar to 990's but the short turn seems a bit tighter to me. Fourth is a semi-closed chamber true large oval. Except for the shape of the water passages, it looks identical to the old -215, -290 and -063 castings. If you have those, they might be a good starting point. Keep in mind that except for the rectangular port heads, all Gen 6 stuff I've seen has non-adjustable valvetrain.
L88Plus is offline   Reply With Quote
Old 04-09-2007, 03:30 PM   #16
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

be carefull a 10.00 comp. iron headed big block will not be like
a 10.00 iron headed small block it will be more prone to ping
not good, stay at 9.25/9.5 and plan on 93 octain. I'm assuming you will
have a very mild duration cam.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 03:37 PM   #17
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Little Mouse View Post
be carefull a 10.00 comp. iron headed big block will not be like
a 10.00 iron headed small block it will be more prone to ping
not good, stay at 9.25/9.5 and plan on 93 octain. I'm assuming you will
have a very mild duration cam.

Yeah I wasn't planning on anything radical. I have not decided on cam specs yet, but I don't go out of control when it comes to cams. I'm taking suggestions for that too by the way.
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 03:56 PM   #18
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

Heres a mild cam for torque a small amount of mid range better
then a pickup cam, hydraulic flat tappit
Crane powermax
Power range 1600-5400
int. dur..050 216
ex. dur..050 228
adv. int. dur. 272
adv. ex. dur. 284
LSA 112
lift int. 515
lift. ex. 510

Cam Facts- good idle, daily usage, off road, towing,
8.75 to 10.75 compression ratio advised.
Cam part #133941, lifters part# 99277-16

Last edited by Little Mouse; 04-09-2007 at 03:59 PM.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 04:00 PM   #19
Durango_Boy
CF Senior Member
 
Durango_Boy's Avatar
 
Member Since: Aug 2006
Location: Columbia Missouri
Send a message via AIM to Durango_Boy
Default

Quote:
Originally Posted by Little Mouse View Post
Heres a mild cam for torque a small amount of mid range better
then a pickup cam, hydraulic flat tappit
Crane powermax
Power range 1600-5400
int. dur..050 216
ex. dur..050 228
adv. int. dur. 272
adv. ex. dur. 284
LSA 112
lift int. 515
lift. ex. 510

Cam Facts- good idle, daily usage, off road, towing,
8.75 to 10.75 compression ratio advised.
Cam part #133941, lifters part# 99277-16

Wow that's really good info. Something to keep in mind is the Gen6 454 is a factory roller. Should I look for a roller cam with those same numbers or will they need to change based on that difference?
Durango_Boy is offline   Reply With Quote
Old 04-09-2007, 04:15 PM   #20
Little Mouse
CF Senior Member
 
Member Since: Apr 2006
Default

Just keep your int. dur. figures pretty simular so the power band
will be roughly the same hydraulic roller will have more lift, a hydraulic
roller will have a little broader power range then a flat tappit cam
so you could go up a little on duration and still be ok as long as
you have the comp. to support it say 9.25 to 9.50.
Little Mouse is offline   Reply With Quote
Old 04-09-2007, 04:15 PM
 
Go Back   Corvette Forum > C3 Corvettes, 1968 - 1982 > C3 Tech/Performance
Reload this Page Big Block 454 Cylinder Head Question.
 
 
 
Reply

Tags
101cc, 215, 454, build, cc, corvette, cylender, cylinder, domed, flat, head, heads, piston, port, square, tops


Thread Tools Search this Thread
Search this Thread:

Click for Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
'73 LS4 454 Aluminum Head Choice? djcwardog C3 Tech/Performance 35 08-21-2005 02:49 PM
427 small block 74 vert C3 Tech/Performance 35 02-28-2003 03:38 AM
How much stoke in an L98 block??? AKS Racing Engine Mods 13 11-07-2001 09:36 PM


All times are GMT -4. The time now is 05:37 AM.


Emails & Password Backup

Search Engine Friendly URLs by vBSEO 3.5.2