GT40X heads vs. F7TE - naturally aspirated + stock cam

shovel

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I'm about to get started on springtime upgrade/maintenance on my 94GT and have a set of X heads (F3ZM 6049 X302) which I believe have 64cc chambers.
I have a stock 5.0HO cam and both 1.6 (SVO) and 1.73 (Scorpion Endurance) rockers to choose from.
For reference these are the numbers the internet claims

1675120714512.png


Questions:
* Going from 61.5cc to 64cc on a stock 9:1 compression ratio means I'd be like 8.8:1 or so - is that going to offset the improved aspiration? I'm staying naturally aspirated on this engine.
* As I understand it the stock cam for a 94 GT is 276/266 duration; .278" lift; 116 lobe center int/115 lobe center exhaust. So that means .444 valve lift with 1.6 rockers and .48 lift with 1.73 rockers. Any reason to go one vs the other?
 

joemomma

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Any reason you're staying with the stock cam? While you're in there it would be a good time to upgrade that as well.
 
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shovel

shovel

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There's not really much overlap in terms of work to remove heads vs. removing cam.. really the rockers are the only duplicated work. I can leave the timing cover on to replace heads or leave the heads on to replace the cam any time in the future if I decide to.

The stock cam idles smoothly and costs $0 and I gotta be honest with you roughly 100% of the time when I see people discussing cams on the internet the ONLY thing they care about is a dumb novelty idle sound, which I can't even begin to understand as a priority.
 

apsmith49921

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There's not really much overlap in terms of work to remove heads vs. removing cam.. really the rockers are the only duplicated work. I can leave the timing cover on to replace heads or leave the heads on to replace the cam any time in the future if I decide to.

The stock cam idles smoothly and costs $0 and I gotta be honest with you roughly 100% of the time when I see people discussing cams on the internet the ONLY thing they care about is a dumb novelty idle sound, which I can't even begin to understand as a priority.
AMEN!!!!! Chop for the gram #chop #choppintheblock #overlap #duration
 

RAU03MACH

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open those heads up put the big chevy valves in dont remember the size
and E cam it
 

joemomma

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I hear you. The stock HO cam does pretty well, as the heads are the big bottleneck on the 302. With that being said, once you open the heads up, there is power to be had with an aftermarket cam and intake. Kind of a snowball in how far you want to take it.
 
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shovel

shovel

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I really hope I don't decide I need more power, last summer I drove my stock 3.8 much more than I drove my GT despite both being driveable, entirely because the 3.8 is running smoothly 100% of the time, while I haven't quite got the tune right on my GT (and I'm starting over with a PiMPxs now..)
In other words what I really want from the car is carefree, smooth, reliable. Power is fine but it's not a priority at all compared to smooth and reliable. My single port 3.8 has no power at all but it's a whole lot more consistent than my GT has been.

The main thing I want from these heads is a torque curve that doesn't fall off a cliff before I'm done accelerating so the car feels better on downshifts and on-ramps. None of this is ever going to involve a stopwatch or a dyno number.
 

joemomma

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I know what you mean. I'd like my car a whole lot better if it didn't fall on it's face at 5k. Sometimes you just want to wind it out a little bit more, and it ain't there lol. A top end kit would do wonders for it.
 

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