Port and Polish


gungfudan

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Headers for an older 3.0 are almost $800, and you won't see huge gains with shortys, especially on a fairly stock engine. For that kind of money, I'd start with an efan conversion and underdrive pulley for $300-400. They'll give you more noticeable improvements in power, will also help with fuel efficiency, and won't require any PCM tuning which extensive porting might. There would probably even be enough $$ left over to buy some roller rockers.
I did have an E-fan installed but it is not enough CFM so I opted to go with the Flex-a-lite fan mentioned on Rogue Performance. I did notice better driving and less strain on the engine along with an acceleration boost. I have the relay all ready to go for a new fan. I also upgraded my alternator to 135 amp. I do plan on going with a set of roller rockers. Did you go with the roller rockers from Tom Morana? Do I even need to port the exhaust side of the head? I have heard people say that it needs to match the exhaust manifold/header that it will cause back flow issues. Sorry for all the questions.
 


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stmitch

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I have Morana's 1.8:1 rocker arms.

I wouldn't ignore the exhaust runners/ports. If you gasket match them, they'll still be the same diameter as the exhaust manifold, or slightly smaller.
My general approach for both the intake and exhaust would be to gasket match the ports, smooth the casting roughness out of the runners, and then really focus on reshaping the bowl area around the valve guides and how it transitions into the runners. Give the air the easiest path into and out of the combustion chamber. If you want to really polish the runners as a final step I'd only do the exhaust ports. Most guys say you don't want the intake runners to be mirror polished or the fuel vapor can do weird things.

Don't disregard the underdrive pulley it's one of the best bang for your buck mods on the 3.0. I saw a dyno chart on another forum that showed gains of something like 8-10hp and 12-14 ft-lbs at the wheels. (That was probably a decade ago, and the forum died so I'm just going from memory) That's really good return considering the fairly low price and easy install though.
 

gungfudan

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I have Morana's 1.8:1 rocker arms.

Don't disregard the underdrive pulley it's one of the best bang for your buck mods on the 3.0. I saw a dyno chart on another forum that showed gains of something like 8-10hp and 12-14 ft-lbs at the wheels. (That was probably a decade ago, and the forum died so I'm just going from memory) That's really good return considering the fairly low price and easy install though.
I can use the stock lifters from what I have been reading about the Morana's 1.8 rockers. Correct?

Second, I asked about the underdirve pulley a while back and some had mentioned that i would have charging issues and issues with my ac compressor.
Is this true? this is the reason I shied away from the underdrive pulley.
 
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stmitch

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Stock lifters are fine. Springs are the weak link in the valve train and can allow valve float at high rpms. Most people don't spend a lot of time at redline, or don't notice valve float there anyway.

The underdrive pulley slows down all of the accessories driven by the serpentine belt. This reduces their effectiveness slightly, so there is a trade off that anybody should understand before buying an underdrive pulley. The only issues I've ever heard about have been from a couple of guys with tons of electrical add-ons like massive stereo stuff or lots of off road lights. The slower alternator might not put out enough juice for those extreme cases, and those guys might have lights that flicker or something. The other 95% of people never notice any drop off, and with the option of LED lights so common now I bet a few of those guys wouldn't have the same problems today that they did 10 years ago. I've never heard any complaints about problems with the water pump, power steering pump, or AC compressor. Ultimately it's your call though. You've got to be able to sleep at night.
 


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