[QUOTE]
Originally posted by Raw Power
Why does everyone like the 4.6L, I don't see why so many people could like the 4.6L over the 5.0L.
I used to e part of this camp, until I bought my 02 GT. I have gained a healthy respect for this engine (gasp! I've even thought about selling my 91 and attendant parts to finance some sort of 4.6 activity, but I'm to cheap for that, I paid for it I'm keeping it till I die)
Because when I seen the bore and stroke of the 4.6L I was shocked, I couldn't believe that ford would make a engine with 3.55in bore and 3.54 stroke and put it into a sports car. The 3.55 in bore is way to small to make any real horsepower without a supercharger. The only reason I say this is because I used to have a camaro with a 305ci and the bore is 3.74in and 3.48in stroke and I was told that I would be unable to make more than 300hp because of the small bore and that I would need at least a 4.00in bore to make some real horsepower.
Okay, if this was the case F1 engines wouldn't be cranking out some neat numbers (nevermind the fact that is like 2 ft/lbs of torque @ a bazillion rpm). By nessecity, production based (and by that I mean utilizing the stuff commonly available to the bulk of hot-roding humanity) components are compromised due to the need for push-rods, affordable components, and other bits and pieces, not to mention low hood lines, ect. the 305 like the 4.6 are smog motors, but that doesn't mean they are crappy performance motors. They do have some inherent advantages compared to their larger bore cousins when it comes to combustion and fuel efficiency. Had engine manufacturers (namely brand - X) decided to build 3-1/2 bore engines in the 60's then people wouldn't make dodo statements like that. Since so many engines use a 4 inch bore and larger. The after market hasn't had to mess with smaller bore engines as much.
Remeber back in the 60's muscle cars were supposed to be cheap thrills, long stroke/small bore technology was and is more costly than short stroke/big bore technology.
The 5.0L is 4.00in bore and 3.00in stroke which is a much better bore and stroke than the 4.6L
Semantics
despite its smallish bore and long stroke, the 4.6 is a better high rpm engine, because of its ohc design, the cylinder heads aren't as comprimised and you can get more flow from a smaller port/valve arrangement (not as many kinks and bends). The small bore means less surface area (reduced crevice volume, less surface area - which means less heat is absorbed by the surrounding surfaces, and the flame front has less distance to travel which reduces the ignition timing requirements allows. I've been told that gasoline burns at an exact rate (BS I say if you take into account things like homgenization and formulation which would affect its rate of burn - just look at how hi-octane fuels work), anywhosit at higher engine speeds the a/f charge has a finite amount of time to burn and act against a piston, the larger the bore, the more time it takes to burn (okay, I begrudginly give this one to long rod motors, but where does the trade off occur in dwell time versus bore size?) meaning unless the piston has sufficient dwell time, its gonna get yanked away before the a/f charge can act against said piston.
All this also has a positive effect on detonation resistance. Which means you can use lower octane fuels (which burn faster comapred to higher octane fuels ~ in the realm of gasoline, of course
), so concievibly an engine using a small bore with a faster buring fuel can make useful power at a higher rpm.
In any event, I guess it comes down to whichever is your weapon of choice. each design has its merits.
Oh and don't think that a 305 is a crappy motor. I think that a 305 with a 4" stroke would make an excellent engine