My very humble contention, and as all can see from reading from the posts, it's probably not worth the trouble you would go through to get the very marginal gains you 'might' see with going 4 valves.
Don't have all my links in front of me but flow for flow and port velocity? You will find that on the intake side, your just not going to do 'much' better than a 3 valve and the exhaust deficit really is negligible. (Won't go into the details on that one at the moment) Also, the 3v has better 'airflow geometry' than the 4 valves and that gives you an advantage with FI. Soo, if you go FI or ever plan on it why on earth would you even consider a 4 valve?
To sum it up, the 3 valve is
Simpler,
Has variable valve timing out of the box,
Better airflow geometry so really best if you are going FI.
Pretty much 'just as good' or within spitting distance of the best 4 valve heads, head size for head size.
I have nothing but respect for the 4 valve engines and heads but I just wish people would give credit where credit is due, the 3 valves heads are no joke and I wouldn't waste your time. Heck, if I had a car and I was looking for a motor swap, I would probably go with the 3 valve!
JonBalli, Thats an awesome NA engine for sure but your not going to run with a built and kenne belled 3v 4.6 liter putting 700+ to the ground. So, yea.. you can knock over some but not all.
Personally, I would go NA.. enjoy that for awhile..then when bored with that, FI- preferably Kenne Bell. Then, if you get bored with that, do a build and put a smaller pully on and enjoy 700++ reliable horsepower. (1000++ crank)
4 valves, great motors but if you got a 3v? nuh uh.
The 2005 Mustang GTR was a concept Mustang Ford put together to show case their 5.0 Cammer 4V engine. They claimed the concept put out 440 hp. I figured if we were arbitrarily quoting 305 hp from an '04 Mach 1 4V why not throw in 440 hp of the 4V cammer. Makes about as much sense...
A 408 stroker will put out 500+ hp and torque and it's two valve...Chevy still uses the "old"? 350/427 in it's Zo6, so less is usually more when it comes to hp and torque...Ford went to multi valve 3-4 because they are more emission friendly.
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"Goose, Hollywood's fine, I want Viper"
1995 Mustang GT Cnv 347(427 stroker being built!) almost done!
1996 Cobra with Kenne Bell 2.1 Supercharger and every other conceivable part you can bolt on it...650hp upgrade in the works
2003 Infiniti M45 V8 340 hp...a methadone treatment for reformed Mustang drivers
A 408 stroker will put out 500+ hp and torque and it's two valve...Chevy still uses the "old"? 350/427 in it's Zo6, so less is usually more when it comes to hp and torque...Ford went to multi valve 3-4 because they are more emission friendly.
The Z06 never had the classic 350 or 427. In 2001 it did have the more emission friendly 5.7 liter LS6 but in English that was a 346 cid. In 2006 they went with the LS7 which is a 428 cid engine.
Ford went to a 2 Valve 281 in the GT partly for emissions reasons. Nothing to do with increasing the number of valves as they still had 2 per cylinder. Ford went to 3 valves in 2005 because they flow better / more power not for emissions. 3 valves instead of 4 was a compromise as 4 valves flow better but are costlier. (more parts).
The 2005 Mustang GTR was a concept Mustang Ford put together to show case their 5.0 Cammer 4V engine. They claimed the concept put out 440 hp. I figured if we were arbitrarily quoting 305 hp from an '04 Mach 1 4V why not throw in 440 hp of the 4V cammer. Makes about as much sense...
Then why not just put in the 5.4 or even a carberated Boss 429?
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07 REDFIRE GT 5 SPEED 3.55 gears
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Tillman Dyno Tune 307HP/322TQ
A 408 stroker will put out 500+ hp and torque and it's two valve...Chevy still uses the "old"? 350/427 in it's Zo6, so less is usually more when it comes to hp and torque...Ford went to multi valve 3-4 because they are more emission friendly.
The new Coyote is emission 'friendlier' still. From what I understand, Ford is returning to 4 valves and double cams so the intake and exhaust cams can be controlled separately. How this helps with emissions I don't know 100% but that's what I hear.
Unless you had an older Stang or money just burning a hole in your pocket I think it's silly to scrap the 3v setup, even for more cubes. Just build right and FI.. shoot, you can get 350+ wheel out of these things NA..
