If you use a VERY good clutch, and have a bone stock motor, you should be OK. I used an 11" Centerforce Dual Friction clutch for my 460 swap, not realizing I could use a 12" with modifications. For the most part, the clutch held up great for the 10K worth of use and abuse I put on it (before the motor let go) When I called tech support about an issue I had, the guy on the other end could not believe that I was going to use an 11" when the 12" was much more superior for a big block. My build was with D0 heads, goodies and goodies, probably 400HP on a good day.

 

400 hp. Whew! I'm not looking for anything close to that. I've been pulling my medium sized horse trailer with 3 large mules with my 74 F250 w/360. Not enough power-have a parade following me on even the slightest of hills. I am going to start hauling an additional mule and just want something that will hold its own on an average hill. So a stock 460 should do the trick. But I have nothing against a 12" clutch if it will go in without a whole bunch of trouble. This 460 already has an edelbrock intake and carb and came with headers-so maybe the 12" is the way to go. I trail ride these mules during the year and use them during hunting season here in western Colorado and hate to think of the whiplash they might experience if I had 400 horses pulling them! Thanks. MM

 

400HP is laughable numbers for a 460 nowadays. If I had known how to get 600 HP without breaking the bank, I would have done it. At the rear wheels, I probably was realistically getting 250-300HP or so. Whatever stock was, I had twice the power. Stock does not boil the tires once you get moving, this thing would, easily. I tried once to dump the clutch in third gear, the truck did not move, but the engine did make alot of noise. In other words, the clutch had no chance in hell of hooking up and making a 5K truck move from a dead stop.

 

I'm curious to know how tall your set up is? measure from flywheel to top of pressureplate. how thick is your total height. If you have one of those 3arm taller systems it will hit. Curious to know what clutch/pressureplate system your running. some are like 4.5 inch tall maybe a little more and will hit. The centerforce system is shorter. One advantage with centerforce is the harder you spin it the harder it bites. Their are other clutch/pressure plate systems out their but I'm familiar with centerforce. L@L products has some photo's of some you can look at to possibly solve your problem.

 

On my Centerforce unit, I had MAYBE 1/4" play between the end of the trans, to contact with the fingers on the clutch, and that is being generous in the guestimating what I remember department. An old timer was saying that you have to use spacers to get things to clear, I guess I lucked out.

 

Hi Guys: Finally got back to doing a bit more on my setup. 12" clutch fit into stock 400 bell housing with a strong 3/8" clearance for shifting fork. Had to trim approx 3/8" off the end of the throwout bearing "sleeve" as it touched the clutch splines. It was easy to trim-I used a plumber's copper pipe cutter and just eased slowly thru the sleeve. It gives an almost perfect cut, but you have to be careful not to apply too much pressure during the cutting procedure as you risk "breaking thru" the final 1/16", but w/care it works great.
My next question is which transmission is preferable: the Borg Warner T-18 4-sp or the New Process 435? I have both but need some suggestions. Thanks. MM ps just in case: my power plant is 460