300 or 240. Pros anc cons of each?

Hey VV

I have a 240 now which runs pretty decent and strong but I want a reman motor while I'm restoring and dont' want to do it in a few years. I know the 300 has more low end torque and I assume lower mpg but I don't need to grind it out in town. What would be the pros and cons of going with either the 240 or 300. I'm not going to rebuild my 240, I'm going with a remanned long block. I figure even with shipping, the price of the long block vs. price of parts, finding a place to do it, and my time to rebuild the 240 is the of same value to me. I don't know the year of my 240 but it has electronic ignition and duraspark module which I plan to keep in place. Undecided if I'm going to keep the core or not. I guess it depends on who needs a good motor.

Thanks for any replies.

First off, so impressed with the difference, I hate to ever even think of putting a 240 back in after running them. My comparison would be twice the motor.
Had a quick240 in my shorty with 3:50 gears, climbed long grades just fine, but got tired of looking for another gear at 80. So,,, dumped them for 3:25's, and found myself looking for second up the same grade. So, considered going back to the 3:50's???????
Killed the 240 and put in a 300, keeping the 3:25's. Now there seems to be such a difference in pulling power, that instead of going back to the 3:50's?? I am thinking I now need to put 3:00's in,,,,,,, HUGE difference, and much easier on the gas pedal. It is a torque monster in my opinion....
vic

300 with 300 with 3.00 does sound like a good combo. They are the same price for the long block. I have 456 and it's going the same time the motor is. I am slowly building my swap meet parts inventory.

Couple of suggestions if I may? First,, I ALWAYS go the adjustable rockers. Perhaps I have posted about it so many times, I cant remember who or how or where or ?????????? No machine shop can possibly use the special gauge for grinding the valve stem tips to the correct height in order for the lifters to be perfectly adjusted. It cant happen!!! The special gauge made to do it, has a tolerance for high and low,, so they try to grind them somewhere in the middle of it. It doesnt allow for cam lobe or lifter wear,,,, or block decking and or head surfacing,, all of that is a guess, that is supposed to be in the gauge setting. I say,, put in adjustable rockers, set them and they are right on the money!!! SO,,,,, with that, if you use an adjustable rocker 240 head, it will bump the compression BACK up slightly from the 300's lower compression ratio AND at the same time give you the adjustable rocker studs... The big sixes have a touchy,, valve oiling setup,, as the oil pressure is known to be on the low side, so,, when the rockers get worn to a point, sometimes the oil will have a hard time coming out the top of the push rods and into the rockers to oil the valves. I have thrown quite a few in the trash can, when I see them not oiling correctly. Another suggestion I have heard about, is that the flange on the back of the crank is weak, and if you don't torque the flywheel on in a normal torquing pattern, the rear seal will leak. They do make a seal saver setup for them,, but about $75 bucks as I recall??? Also,, don't forget you are putting in more cubes,, so a four row 240 radiator and a factory shroud would be a priority on my list also.
vic

Thanks Vic.

The motor I'm looking at has adjustable rockers. so when do you know when to adjust em? The 4 row radiator was sitting on my porch today. It just came in. I wasn't aware of the the seal saver setup. Where do I find the torque pattern? I dont' see it in the repair manual. My new wiring harness has a circuit for a cooling fan so I'll have that in there too.

Be careful and confirm that indeed they are adjustable, the non adjustable s look very close, except for they simply tighten all the way down or are the pedestal type. They can be converted over if not.
I dry adjust them before I fire, warm up, and then fine adjust them while running. I took an old valve cover, marked exact center for a socket on each rocker, cut holes with a hole saw to keep the oil splash down.
CORRECT way to adjust, after warm up, is,,,,,, back off the rocker until you here it clattering,, then adjust until you JUST stop making clatter,, then go down 3/4 of a turn slowly. The book calls for 1 and 1/2 turns, but I don't like that adjustment myself. The 3/4 turn, will not allow the lifter to over pump and bend a valve if you happen to over rev. Have used it for MANY years.
Good one on you for the radiator, and personally, on any build, I no longer try to use a mechanical fan, as it makes no sense to me on a nice build.
My opinion only for what its worth. A mechanical fan at idle in stop and go, is not pulling or cooling as well as it can, also,, it is NOT cooling the carb heat soak out, when parked. So,, in my thinking, I set them up with a relay to be hot all the time, meaning hot electrical. The thermostat turns it on when it gets to operating temp, and shuts down when parked, WHEN it is cooled off. I have been using the setup for years, and never drained a battery yet.
On the flywheel,, simply go in 25 lb increments, and use a normal torquing pattern until you reach the recommended torque in the book. I cannot scientifically prove it, but it looks like it could distort very easily, and have had problems there before,, so it cant hurt to do it correctly. Something I am sure a lot of us, have simply nailed with a big impact wrench. LOL.
Check out the Taurus fan setup, the shroud and the low profile two speed motor are about $36 bucks at the bone yrds. Here is a link to the setup,, problem though is the alternator upgrade. However, it makes to much sense also. I use the Mustang 3G alternator, it puts out 90 amps at idle,, which is what you really need to run everything. Most of all, the high CFM fan motor,, is sucks amps.....also, its a single wire unit. Paid $195 for my new one, chromed, etc,,,, but have gotten two at the yrds for about $20 bucks each.
if an auto I always run my remote fan cooler also,,

vic