Vortec Headers?
Thread Starter
Instructor
Joined: Jun 2019
Posts: 232
Likes: 14
Vortec Headers?
I'm reading the "small print" about the BluePrint engine I want to put in my '81. The aluminum heads say they are "similar to vortec cast iron heads." They have raised exhaust ports and are .500" higher than the vortec. They suggest that because of the raised exhaust ports, header clearance may be an issue and to use a header designed for the vortec heads that route the pipes up high.
Has anyone dealt with this and/or have header recommendations?
Has anyone dealt with this and/or have header recommendations?
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
and it is not Vortec. it is raised ports. 1st gen thru vortec all used same exhaust port config until aftermarket decided this is a better exhaust port angle. they are right, but sometimes engine compartments disagree.
Pro
Joined: Oct 2009
Posts: 664
Likes: 89
From: Marysville Ohio
Exhaust ports raised .500 and .600 sounds really high. Last time I looked at AFRs website (which was just in the last couple weeks) the most I saw was .250 (which is what I have with my AFR 210s,and with 195s I used in the past.) Is this new or not a small block?
Last edited by cooper9811; Jul 10, 2019 at 11:29 AM.
Intermediate
Joined: Jul 2019
Posts: 30
Likes: 9
The exhaust ports on BluePrint's H8002K small block heads are raised .300". The spark plugs are also configured into the chambers like Vortecs because the heads have a Vortec type heart shaped combustion chambers. The two center plugs are 1/2" closer together than the 1970's era 882 type factory heads.
I believe many guys here on the forum with BluePrint's engines that include those heads are using standard sbc Hooker headers for C3 Vettes without a problem. I am sure someone here could get the part number for you.
If you want to run shorty or block hugger headers, use ones designed for angle plug heads. They keep the pipes away from all the spark plugs. Speedway Motors has a set that BluePrint has tested and worked great.
I believe many guys here on the forum with BluePrint's engines that include those heads are using standard sbc Hooker headers for C3 Vettes without a problem. I am sure someone here could get the part number for you.
If you want to run shorty or block hugger headers, use ones designed for angle plug heads. They keep the pipes away from all the spark plugs. Speedway Motors has a set that BluePrint has tested and worked great.
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Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
The exhaust ports on BluePrint's H8002K small block heads are raised .300". The spark plugs are also configured into the chambers like Vortecs because the heads have a Vortec type heart shaped combustion chambers. The two center plugs are 1/2" closer together than the 1970's era 882 type factory heads.
I believe many guys here on the forum with BluePrint's engines that include those heads are using standard sbc Hooker headers for C3 Vettes without a problem. I am sure someone here could get the part number for you.
If you want to run shorty or block hugger headers, use ones designed for angle plug heads. They keep the pipes away from all the spark plugs. Speedway Motors has a set that BluePrint has tested and worked great.
I believe many guys here on the forum with BluePrint's engines that include those heads are using standard sbc Hooker headers for C3 Vettes without a problem. I am sure someone here could get the part number for you.
If you want to run shorty or block hugger headers, use ones designed for angle plug heads. They keep the pipes away from all the spark plugs. Speedway Motors has a set that BluePrint has tested and worked great.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Here's a bit of Help figuring raised-port headers' position in bay
HS trig
sbc & BBC are 90* motors ... cylinder banks are 45* from X axis (and Y) ... use sine of 45* = 0.707xxxxxxxxxxxxxxxxxxx
if ports are raised 0.300" ... then sin45* x 0.3" = 0.212xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.212"
if ports are raised 0.500" ... then sin45* x 0.5" = 0.354xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.354"
if ports are raised 0.600" ... then sin45* x 0.6" = 0.424xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.424"
another example but with an additional calc ... 60 degree motors require a little different trig.
Chevy also made several 60* V6 motors (60* between banks & from X) such as iron head & block pushrod V6 2.8L in early S10 pickups etc.
As the cylinder banks move closer to Y axis, raised ports move proportionally (than 90* motor) Farther UP BUT proportionally Less Outboard.
Banks are 30* from Y axis and 60* from X axis.
60* motor: sine of 60* = 0.866xxxx" AND cosine of 60* = 0.5"
if ports are raised 0.300" ... then sin60* x 0.3" = 0.259xxxx" AND cos60* x .3" = 0.150" ...
... in relationship to crank, ports are moved UP (y) some 0.260" AND moved Outboard (x) 0.150"
perhaps above might help some to pre-determine exhaust clearance
sbc & BBC are 90* motors ... cylinder banks are 45* from X axis (and Y) ... use sine of 45* = 0.707xxxxxxxxxxxxxxxxxxx
if ports are raised 0.300" ... then sin45* x 0.3" = 0.212xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.212"
if ports are raised 0.500" ... then sin45* x 0.5" = 0.354xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.354"
if ports are raised 0.600" ... then sin45* x 0.6" = 0.424xxxx" = in relationship to crank, ports are moved UP (y) AND moved Outboard (x) some 0.424"
another example but with an additional calc ... 60 degree motors require a little different trig.
Chevy also made several 60* V6 motors (60* between banks & from X) such as iron head & block pushrod V6 2.8L in early S10 pickups etc.
As the cylinder banks move closer to Y axis, raised ports move proportionally (than 90* motor) Farther UP BUT proportionally Less Outboard.
Banks are 30* from Y axis and 60* from X axis.
60* motor: sine of 60* = 0.866xxxx" AND cosine of 60* = 0.5"
if ports are raised 0.300" ... then sin60* x 0.3" = 0.259xxxx" AND cos60* x .3" = 0.150" ...
... in relationship to crank, ports are moved UP (y) some 0.260" AND moved Outboard (x) 0.150"
perhaps above might help some to pre-determine exhaust clearance