Plug Exhaust crossover?

weagle · 07-12-2001, 09:14 PM

I am installing a set of aluminum heads on my 89GT. I have a cobra intake and I wonder if there is anything to gain from plugging the exhaust crossover. The smog pump has been removed.

Lexicon · 07-13-2001, 12:14 PM

The exhaust crossover on the the H pipe section???

You never wish to plug this crossover. Crossovers are designed to aid in the equalization of the exhaust gas pulses and aid in creating a smoother exhaust flow out of the rear end. If you were to block such passage way you could possibly loose performance and I bet a noticeable degradation in exhaust sound quality could rear its head.

jimberg · 07-13-2001, 12:18 PM

I think he's referring to the air tube connecting the back of the heads. There's no point in having the air tube on the back of the heads if you don't have an air pump.

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351W 89 Mustang GT Convertible

429AL · 07-13-2001, 12:47 PM

Quote:

Originally posted by jimberg:
I think he's referring to the air tube connecting the back of the heads. There's no point in having the air tube on the back of the heads if you don't have an air pump.

do they make a plug for these .

89 Cobra LX · 07-13-2001, 12:50 PM

I've seen them plugged with bolts before. I'm not sure what size.

------------------
Eric - 89 Mustang LX coupe
302 - Cobra Intake - GT40p heads - TFS stage 1 cam - FRPP 1.6 roller rockers - Naturally Aspirated
3:73 gears - KYB shocks and struts - Eibach springs - HPM Mega-bite Jr lower control arms - HPM upper control arms

302 LX Eric · 07-13-2001, 12:56 PM

jimberg has it right.

I have TFS TW heads on my coupe and purchased the proper plugs directly from Trick Flow for like $6.

E

------------------
1991 5.0 LX Coupe - 38,000 miles

13.17 @ 106.14 mph w/ 2.138 60'

jimberg · 07-13-2001, 02:40 PM

The plugs for the front are the same plugs for the back. Short 5/8" coarse thread bolts should work.

This is what the real one looks like.

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351W 89 Mustang GT Convertible

[This message has been edited by jimberg (edited 07-13-2001).]

[This message has been edited by jimberg (edited 07-13-2001).]

07-12-2001, 09:14 PM	#1
weagle Registered Member Join Date: Jan 2001 Location: northwest fl Posts: 14	Plug Exhaust crossover? I am installing a set of aluminum heads on my 89GT. I have a cobra intake and I wonder if there is anything to gain from plugging the exhaust crossover. The smog pump has been removed.

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07-13-2001, 12:14 PM	#2
Lexicon Registered Member Join Date: Jun 1999 Location: Evansville, Indiana Posts: 182	The exhaust crossover on the the H pipe section??? You never wish to plug this crossover. Crossovers are designed to aid in the equalization of the exhaust gas pulses and aid in creating a smoother exhaust flow out of the rear end. If you were to block such passage way you could possibly loose performance and I bet a noticeable degradation in exhaust sound quality could rear its head.

07-13-2001, 12:18 PM	#3
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I think he's referring to the air tube connecting the back of the heads. There's no point in having the air tube on the back of the heads if you don't have an air pump. ------------------ 351W 89 Mustang GT Convertible

07-13-2001, 12:50 PM	#5
89 Cobra LX Don Corlione Join Date: Jun 2001 Location: Omaha NE USA Posts: 491	I've seen them plugged with bolts before. I'm not sure what size. ------------------ Eric - 89 Mustang LX coupe 302 - Cobra Intake - GT40p heads - TFS stage 1 cam - FRPP 1.6 roller rockers - Naturally Aspirated 3:73 gears - KYB shocks and struts - Eibach springs - HPM Mega-bite Jr lower control arms - HPM upper control arms

07-13-2001, 12:56 PM	#6
302 LX Eric or '331 LX Eric' Join Date: Jan 1999 Location: Columbus, Ohio Posts: 2,142	jimberg has it right. I have TFS TW heads on my coupe and purchased the proper plugs directly from Trick Flow for like $6. E ------------------ 1991 5.0 LX Coupe - 38,000 miles 13.17 @ 106.14 mph w/ 2.138 60'

07-13-2001, 02:40 PM	#7
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	The plugs for the front are the same plugs for the back. Short 5/8" coarse thread bolts should work. This is what the real one looks like. ------------------ 351W 89 Mustang GT Convertible [This message has been edited by jimberg (edited 07-13-2001).] [This message has been edited by jimberg (edited 07-13-2001).]