Heads and Cam final debate!
10-02-2007, 10:45 AM
#31
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RE: Heads and Cam final debate!
ORIGINAL: Wickerbill
Which 2V 5.0L GT engines are you talking about?? I never knew of ANY being overhead cam. And any ideas on opening up that manifold?? Kinda hard to do any machine work on a composite intake manifold. And what is too aggressive of a cam duration in your opinion? More cam duration means that the valves stay open longer, meaning you have more intake air pulling in on downstroke and after compression the exhaust valves stay open longer so exhaust gases can escape more effeciently. Also with more duration comes the need to retard or advance the timing so that on split overlap your piston doesnt hit the valves.
if u wnat to get a good idea about porting the heads, just take a look at the old 2 valve gt's. granted they have 2 more cylinders, but the over head cam design is the same. start learning to do the math in the head work, or talk to someone who knows a great deal about it. more air and fuel = more power. heck try and open up the intake maifold a bit. let more air into the runners where they flow into the heads themselves. yea we have V6's but the great thing about the internal combustion engine is... they all work on the same concept.
10-02-2007, 03:40 PM
#33
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RE: Heads and Cam final debate!
Wickerbill, what's ur input on an engine or body shop doing a port and polish heads job and cam regrind? How much different do u think they would be from a site like Supersix Motorsports heads and cam? Good gains or no? I want to hear a mechanics opinion.
10-02-2007, 04:33 PM
#34
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RE: Heads and Cam final debate!
first off a body shop has no buisness doing machine work. The only people that would be qualified to do this is a place that does nothing but machine work, you know like a race engine shop. There is one in Kingsport TN called Quick Way Engine company that does all my work. Port and polish alone will give you some gains but theres no way I could even figure the exact numbers. This work done at a good shop would be in the $500 range. But for the best gains your talking complete head job,(i know we joke about that all the time here!), your talking valve grinds, seats, new guides, and springs plus the port and polish. And to do all that work you need to know what lift and duration cam your going to run. All this work for two heads would run into the thousands. Now in your case your going to need to pay someone to research and install all this or all that custom work might not amount to 5hp. So IMO unless you are very wealthy AND know exactly what you are doing your best bet would be wait till something is offered for the 4.0L that a mechanic could bolt on for you. Remember anything at all you do now would have to be custom work with some custom parts.
10-02-2007, 04:34 PM
#35
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RE: Heads and Cam final debate!
ORIGINAL: Wickerbill
since he said "old" 2 valve GT engineI was assuming he was talking about 5.0, since the 4.6 has since replaced the 5.0 in 1995 or 1996 and became the new GT engine.
since he said "old" 2 valve GT engineI was assuming he was talking about 5.0, since the 4.6 has since replaced the 5.0 in 1995 or 1996 and became the new GT engine.
10-02-2007, 05:02 PM
#37
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RE: Heads and Cam final debate!
i wouldnt base how much of a gain you are going to ge ton what 4.6's are getting though. That is a completely different engine, with completely different flow characteristics stock and modded, a different design, etc. Just because it is sohc with 2v per cylinder does not mean it is going to see similar gains. That is like saying an ls1 is going to see similar gains to a 5.0. not even close!
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