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Discussion Starter · #1 ·
I bought a mark viii motor from the salvage yard that i had planned to build up. I am wondering if it would be better to use the b heads that came with this motor and get the cobra intake or bolt my patriot stage 2 heads onto this block? I plan on going with a turbo kit if that makes a difference.
 

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I would say the ported b heads would out-flow the patriot heads, especailly up top. Everything I've heard is that b heads love boost
 

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April 2012 ROTM
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go for the 4 valve heads and dont look back lol
 

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Not a Rational Car Guy
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03/04 4V Heads
 

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arent b ports a pain in the ass to get intakes for though?
 

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Not a Rational Car Guy
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arent b ports a pain in the ass to get intakes for though?
I don't know if there are any aftermarket options, but a stock 96-98 intake fits the b heads and makes a nice difference over the stock mark viii intake. People are claiming 50 rwhp in boosted applications where they replace the stock mark viii intake with a ported cobra intake
 

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**** patriot heads
 

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i like good head
 

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Priest of the Car Gods
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I'm a little hesitant to go with the b heads because I DD my car, but since they're already on the motor I can't justify spending money to get other ones.
I DD a b-port Cobra with busted IMRC plates (stuck open). What's the supposed issue?
 

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That writeup just makes it sound like it's gonna be a dog until like 5000 rpm and then shine. Sounds like the c heads are nice at lower rpms but kinda choke out. I already have b heads so that's what I'll go with.

Rev, you have any problems with the b heads down low? How about a difference between working and stuck open IMRC plates?
 

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Discussion Starter · #16 ·
I am running a single 70mm turbo kit, stock crank with eagle h beam rods, i have brand new cp pistons in my gt that are 10 to 1 compression have only been in my car for 5k miles will they work with the 4v? Will my gt computer work with this motor with some tune work?
 

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Discussion Starter · #17 ·
So if i dont want to use the imrc set up can i just leave the vacuum lines unhooked to them or should i remove the plates?
 

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Rev, you have any problems with the b heads down low?
Not in the least. Basically you drive it like a typical 4-cylinder - you only have it under 2k rpm if you're pulling away from a stop sign in 1st gear, cruise at ~2200 rpm, and you start feeling power come on around 3500 after which she pulls all the way to the fuel cutoff (7k). I think you'd only think there was a problem if you were expecting the powerband of a pushrod, where you can cruise at 1100rpm without lugging the motor.

How about a difference between working and stuck open IMRC plates?
Honestly, I'm not sure my IMRCs have ever worked, because if they just stopped working recently (as would be indicated by my recent CEL), the difference between IMRCs working and not is only visible at the pump (I've lost about 1 mpg city, 2mpg highway). There's NO difference in feel.
 

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So if i dont want to use the imrc set up can i just leave the vacuum lines unhooked to them or should i remove the plates?
cant run imrcs on a gt computer..
u need to buy some imrc deletes
 

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I am running a single 70mm turbo kit, stock crank with eagle h beam rods, i have brand new cp pistons in my gt that are 10 to 1 compression have only been in my car for 5k miles will they work with the 4v? Will my gt computer work with this motor with some tune work?
I think your computer will work but you'll have to get a different tune since the computer thinks it's only runnning 2 valves when it's really running 4.

I probably wouldn't run 10:1 compression on a boosted motor, unless you run pretty low boost.
 
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