Big block header issue
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Big block header issue
Finally got aroud to dropping the BB 427 in the hole.
I have 3931063 casting oval port heads.
The issue is the 2 1/8 in primary headers are too big for the head port mounting surfaces, there is a 1mm of header flange coverage on the machined head surface....... ( gasket will last all of 5 mins)
Has any one had this issue? looks like new heads are the answer
Richie
I have 3931063 casting oval port heads.
The issue is the 2 1/8 in primary headers are too big for the head port mounting surfaces, there is a 1mm of header flange coverage on the machined head surface....... ( gasket will last all of 5 mins)
Has any one had this issue? looks like new heads are the answer
Richie
Race Director
Joined: Jan 2000
Posts: 13,024
Likes: 2,266
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
I don't think I ever hit that before...and as much as new heads are great....a better choice might be a set of 1-7/8" headers. 2-1/8" are way too big for a 427 oval port motor.
JIM
JIM
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
I got a 1-7/8" Hooker super comp. and I already have a serious ground clearance issue!, I spend at least 40-50 hours working on them to fit my car, and now I have to remove them because of the ground clearance issue. I will NEVER buy Hookers again, I had to dimple a couple of places, and had to use the angle grinder to clear the flange from hitting the lower head bolts, and the passenger side collector is already hitting the floor. It just like they started fabricating headers for C3s yesterday! , I will buy from Hedman this time. Sorry for the negative post, but I have to steam out a bit!
Drifting
Joined: Oct 2005
Posts: 1,528
Likes: 148
From: East London/SW Essex UK
Doing the opposite thing shortly - currently have Hedman 1 7/8" headers - they fit great on 427/390 - passenger side literally falls in to place - drivers side requires removal of alternator and clutch 'Z' bar - collectors ARE close to floorpan. Will be fitting 2 1/8" Super Comps to my Brodix headed stroker - whether the additional flow will add any HP/TQ remains to be seen! - hope ground clearance won't be an issue!
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Yeah I know primary tubes are too big, they are side pipes so did not have much choice, might force me to change the heads now, like to get the compression down to pump gas level, these heads are 100.9 chambers.
Hope to go with some small rectangle ports.
I have shipped these pipes from your side of the world, so they literally owe me thousands, so on the hunt for some local used heads.
Will post some pics
Richie
Richie
Last edited by richiev88; Jul 23, 2011 at 04:03 PM.
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Doing the opposite thing shortly - currently have Hedman 1 7/8" headers - they fit great on 427/390 - passenger side literally falls in to place - drivers side requires removal of alternator and clutch 'Z' bar - collectors ARE close to floorpan. Will be fitting 2 1/8" Super Comps to my Brodix headed stroker - whether the additional flow will add any HP/TQ remains to be seen! - hope ground clearance won't be an issue!
Intermediate
Joined: Jun 2011
Posts: 42
Likes: 0
I got a 1-7/8" Hooker super comp. and I already have a serious ground clearance issue!, I spend at least 40-50 hours working on them to fit my car, and now I have to remove them because of the ground clearance issue. I will NEVER buy Hookers again, I had to dimple a couple of places, and had to use the angle grinder to clear the flange from hitting the lower head bolts, and the passenger side collector is already hitting the floor. It just like they started fabricating headers for C3s yesterday! , I will buy from Hedman this time. Sorry for the negative post, but I have to steam out a bit!
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Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Finally got aroud to dropping the BB 427 in the hole.
I have 3931063 casting oval port heads.
The issue is the 2 1/8 in primary headers are too big for the head port mounting surfaces, there is a 1mm of header flange coverage on the machined head surface....... ( gasket will last all of 5 mins)
Has any one had this issue? looks like new heads are the answer
Richie
I have 3931063 casting oval port heads.
The issue is the 2 1/8 in primary headers are too big for the head port mounting surfaces, there is a 1mm of header flange coverage on the machined head surface....... ( gasket will last all of 5 mins)
Has any one had this issue? looks like new heads are the answer
Richie
