4 valve mustang gt
#12
^^^ True, bu all that work just to have 8:1 compression, and not even 300rwhp. the only way it would be worth it was if you already ahve agressive cams, and ported heads for the 4v. and flat tops as well. you'll need the timing cover, intake mani, heads, cruise control cable, and alot of tiny things. just getting the whole motor is alot easier
#14
What about the fact that youre almost losing 2 whole points of compression??? Its been done. You can do full bolt ons and still have the same power as a 4v headswap and it will be a better, more useable power because even at the lower compression, the 4v heads will still make power way up in the RPM's. Now like said, if you have flat top pistons, you'd be better off. But in comparision, the machs have like what a 10:1 compression or something...the PI motor with a 4v headswap is going to be 8:1 compression. So there alone you lose a lot of power. Doesnt matter how much the heads flow. If youre pushing low compression without a blower on a 4v, your car just isnt going to feel peppy at all on the street.
#15
If you do the 4 valve swap you have to get a different timing chain. But from what i have heard about the new trick flows i wouldn't do it unless you can find a Cobra being sold for parts, and the compression issue mentioned above. Heard the air flow on the new trick flows compares Very well with 4 valves
#19
i have a auto 98gt that just had a 4v swap at the end of last summer and i would say to stay 2v and go FI. if not, do the 4v swap with plans of FI in the near future. i do have a little more power now but im still NA and need to get a turbo. the main difference is it pulls all the way up to 6k rpm instead of lossing power around 4800 rpm like before. tho the 4v motor is so much better to look at, as of right now for me it wasnt worth the money i spent on the job. once the turbo goes on it will probably be a different story