K5 Blazer Forums  
Home of the 1969-91 K5 Blazer/Jimmy including GM Trucks and Suburbans.  
Go Back   CK5 Forums > General Discussion > The Garage

Remove these ads.

Reply
 
Thread Tools Display Modes
Old 06-15-2010, 10:05 PM   #1
pismorat
Registered User
 
Join Date: Oct 2002
Location: California
Posts: 527

i Trader: (0 )

Oval port headers on Rect. port heads?

I am putting my 383 full roller stroker in my wife's '69 C10. It has GM Perf. heads with angled plugs and rectangular ports. I ordered a set of Hedman Hedders to clear the angled plugs, but they ended up being oval port...am I going to have a problem if I try to run these?
pismorat is offline   Reply With Quote
Sponsored Links



Remove these ads.
Old 06-16-2010, 06:13 AM   #2
pismorat
Registered User
 
Join Date: Oct 2002
Location: California
Posts: 527

i Trader: (0 )

Since no one replied yet, I assume it is a bad combination...
pismorat is offline   Reply With Quote
Old 06-16-2010, 06:31 AM   #3
folkenheath
Supporting Member
Worthless Trash
 
folkenheath's Avatar
 
Join Date: Nov 2004
Location: Wisconsin
Posts: 3,580

i Trader: (3 )

Quote:
Originally Posted by pismorat View Post
I am putting my 383 full roller stroker in my wife's '69 C10. It has GM Perf. heads with angled plugs and rectangular ports. I ordered a set of Hedman Hedders to clear the angled plugs, but they ended up being oval port...am I going to have a problem if I try to run these?
Did someone severely port on those heads? As far as I know there is no such thing as a rectangular exhaust port. There are D-ports. And all small block Chevy's are pretty much rectangular port intake ports, so no one ever uses that term on the small block. But either way, as long as you have enough material to pinch the header gasket and not leak they should be fine. If they are D-ports, usually the header will just be a little too large at the bottom, but still seal against the flat gasket surface underneath. Unless they are a large race D-port or something.
__________________
83 Shortbed, 550 hp 489 BBC EFI, TH400, Twin Stick NP205, 14BFF w/Detroit & disks, D60 w/detroit + 35 spline stubs, 4.10 gears, 6" lift, 36" TSL, custom radius arm front suspension with 14" travel coilovers and air bumps. The build... http://coloradok5.com/forums/showthread.php?t=281710

Quote:
Originally Posted by TerryD View Post
I explained the difference between a motor that makes noise and a motor that makes power.
folkenheath is offline   Reply With Quote
Old 06-16-2010, 07:54 AM
Posted in reply to folkenheath's post starting "Did someone severely port on those..."
  #4
Stomis
Supporting Member
Professional Amateur
 
Stomis's Avatar
 
Join Date: Nov 2007
Location: Roseland VA/PtPleasant NJ
Posts: 8,446

i Trader: (5 )

Yeah in fact oval headers on a D port head is ideal. Creates whats known as a reversion dam which aids in exhaust scavenging with a free flowing exhaust. Basically it doesnt let the exhaust gasses cycle back into the head but instead aids in drawing more gasses out accelerating exhaust flow.
__________________
1994 SCSB c1500 11.25:1 5.3, Trick flow 205 GenX heads, s10 nv3500, 4.30 Tru Trac 8.5in 10b w/ 9in outers
Ext Cab S10 Truggy Tube frame, S/C 3.8, RA dana 44 front, Ox ford 8.8 rear, one of these days...



- Vinnie
Stomis is offline   Reply With Quote
Old 06-16-2010, 02:44 PM
Posted in reply to Stomis's post starting "Yeah in fact oval headers on a D port..."
  #5
pismorat
Registered User
 
Join Date: Oct 2002
Location: California
Posts: 527

i Trader: (0 )

Cool, so should I just get a good set of gaskets(probably metal) that fit the d-port so they will last and not impede the air path? Or do I get a set that matches the oval port?
pismorat is offline   Reply With Quote
Old 06-16-2010, 07:37 PM
Posted in reply to pismorat's post starting "Cool, so should I just get a good set..."
  #6
Stomis
Supporting Member
Professional Amateur
 
Stomis's Avatar
 
Join Date: Nov 2007
Location: Roseland VA/PtPleasant NJ
Posts: 8,446

i Trader: (5 )

Quote:
Originally Posted by pismorat View Post
Cool, so should I just get a good set of gaskets(probably metal) that fit the d-port so they will last and not impede the air path? Or do I get a set that matches the oval port?

Get a set to match the ovals.
__________________
1994 SCSB c1500 11.25:1 5.3, Trick flow 205 GenX heads, s10 nv3500, 4.30 Tru Trac 8.5in 10b w/ 9in outers
Ext Cab S10 Truggy Tube frame, S/C 3.8, RA dana 44 front, Ox ford 8.8 rear, one of these days...



- Vinnie
Stomis is offline   Reply With Quote
Old 06-16-2010, 07:44 PM   #7
4X4HIGH
Supporting Member
Registered User
 
4X4HIGH's Avatar
 
Join Date: Dec 2001
Location: Pleasanton, CA.
Posts: 21,690

i Trader: (20 )

GM of the month Winner
Almost all SBC exhaust ports are square with the exception of some Corvette heads that had a D shaped exhaust port.

I have found that the Fel-Pro 1444 gaskets work best on most headers.
__________________
1989 blazer, 350/700R4/NP241, 8" lift, D60/14FF w/4.56's and Detroits, hydro assist, 35" BFG Mud
Scott
4X4HIGH is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

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

Forum Jump


All times are GMT -7. The time now is 10:11 PM.


Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.