Intake Heat Riser Block-off?
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 31
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From: Flower Mound Texas
Intake Heat Riser Block-off?
I have searched as many threads as I can find, but have not found complete answers per se.
350 SBC engine combo will be Dart Iron Eagle 165 heads, Edelbrock Performer intake, Holley 650 with electric choke, Comp XE262, and headers.
Essentially car will only be driven in warm weather - Texas.
Both heads and intake have exhaust heat "feature"...what is the best way to block it off? Or do y'all think I should just leave it open?
Thanks!
350 SBC engine combo will be Dart Iron Eagle 165 heads, Edelbrock Performer intake, Holley 650 with electric choke, Comp XE262, and headers.
Essentially car will only be driven in warm weather - Texas.
Both heads and intake have exhaust heat "feature"...what is the best way to block it off? Or do y'all think I should just leave it open?
Thanks!
Race Director
Joined: Jan 2000
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Gaskets with the metal heat shields are the easiest.
JIM
JIM
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you don't have a heat riser valve installed, it doesn't really matter whether you block off the manifold passages or not. It might keep the intake a bit cooler with them blocked off, but I doubt that you will ever notice the difference in mileage, performance, or appearance of the paint on the intake. So, if your gasket kit comes with block-off inserts, use them....if it doesn't, forget about it.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
It does make a difference. But not a huge one. Cooler intake charge is denser & more powerful.
Regionally, all lower class circle track chevy have production heads and, at most, aftermarket intake w/ Xover. Every one of them is blocked ... both driver & pass sides.
Composition gasket material alone will quickly burn through.
Thin aluminum inserts that often come with gaskets ... thin Al burns thru also.
Thin shim steel is the solution ... cut em & silicone em to heads.
On a street car with a divorced choke that depends on Xover heat ... that choke must be rigged open (inoperative).
Regionally, all lower class circle track chevy have production heads and, at most, aftermarket intake w/ Xover. Every one of them is blocked ... both driver & pass sides.
Composition gasket material alone will quickly burn through.
Thin aluminum inserts that often come with gaskets ... thin Al burns thru also.
Thin shim steel is the solution ... cut em & silicone em to heads.
On a street car with a divorced choke that depends on Xover heat ... that choke must be rigged open (inoperative).
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
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Verdad Gallardo
Team Owner
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From: Crossville TN
If you don't have a heat riser (valve) in the system, there is nothing to force the exhaust heat into the intake manifold passage. Flow is 'deadheaded' and the exhaust/heat will exit through the pipes. Coolant in engine will keep the entire manifold at engine operating temperature. Intake manifold will not discolor (as long as you use an "engine-friendly" paint).
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
If you don't have a heat riser (valve) in the system, there is nothing to force the exhaust heat into the intake manifold passage. Flow is 'deadheaded' and the exhaust/heat will exit through the pipes. Coolant in engine will keep the entire manifold at engine operating temperature. Intake manifold will not discolor (as long as you use an "engine-friendly" paint).
