720 gas how big

[720puller]

I am wanting to know how much bore and stroke can be put into a 720 gas? I have been looking at one, but it is missing alot of parts. Thought about just building a puller out of it. Also on a 720 (gas or diesel) how much weight can be lost removing the rockshaft housing, hyd, and pto? Thank you for any information you may have.

 

[730 DIESEL PULLER]

DONT KNOW ABOUT THE CUBES,,,BUT I HAVE BEEN TOLD THAT GOIN TO A FLATBACK, NO PTO, WILL LOOSE ABOUT 600 lbs...

 

[Anonymous-0]

Hay diesel puller. I have a head with large valves that i had on my 730 when i pulled it.I had it flowed tested and i think i have the ###. If interested please call 563-744-3814 Fritz

 

[JDGnut]

A friend has a 730 with a little over 600 cubes.. built like most would build a 600 cube G/70.. just don't think there is room to go much bigger...
JDGnut

 

[720puller]

How much stroke would that be, around 8" maybe?

 

[Molinesam]

720puller, My pulling buddy has a 70 gas @ 900 cubes. Stock 70 is 5.875 * 7.00 & stock 720 gas is 6.00 * 6.375, so don't about the 720. Very serious money to go to 900.I grew up on 2 bangers & no disrespect intended here, but a big cube JD running super can't handle 500 cube Ollies or M's @ 6000# or 605 MM's @ 9000#. Big MM's cost a fraction as much to build for twice the hp. Big M's & Ollies are fairly pricy too.
Build it for stock 3.5 mph class for much less $$ & much more fun.

 

[JDGnut]

Using a stock block without sleeves, it would be in the 9 3/8 range.. There just isn't the room in the 720/730 like there is in the 70/G's... nice thing is the plugs in the head.. and better air flow..
I'm not saying you cann't go bigger.. but it will be more work than other tractors..
JDGnut

 

[jd b puller]

(quoted from post at 21:26:25 11/17/08) 720puller, My pulling buddy has a 70 gas @ 900 cubes. Stock 70 is 5.875 * 7.00 & stock 720 gas is 6.00 * 6.375, so don't about the 720. Very serious money to go to 900.I grew up on 2 bangers & no disrespect intended here, but a big cube JD running super can't handle 500 cube Ollies or M's @ 6000# or 605 MM's @ 9000#. Big MM's cost a fraction as much to build for twice the hp. Big M's & Ollies are fairly pricy too.
Build it for stock 3.5 mph class for much less $$ & much more fun.

Hi Sam, when you say that a 900CI JD can't keep up with a 500CI Ollie, are you referring to a 10% RPM, 3.5MPH, or the no speed limit, 3000 RPM class where the Deere is turning 1500 and the Ollie is turning 3000?

You said "Big MM's cost a fraction as much to build for twice the hp." - what kind of HP at what RPM and what $ are you talking?

Thanks,

 

[Molinesam]

jd b puller good morning, Big hp is not needed in 3.5 mph 10% classes. Big cube big $$ bullets belong in 12 mph classes. I really like the 5 & 7.5 mph classes for tractors that are more than stock but fall short of full supers.
Big MM's ( 700/850 cube )are more economical since they can be built with readily available bolt on parts with no stroking. Much bigger ( 900/1300 ) with 1/2 to 1" stroke. Stroked motors do get expensive. hp? 250 to 400+ @ 2500/3000 rpm. I'm no builder or expert on any of this, just my observations & experiences. Good luck with that b.

 

[jd b puller]

hey Sam, thanks for clarifying. For a minute there I was thinking you were suggesting a 900 CI JD 70 couldn't compete at 3.5MPH!

I was hoping to get down to One of your SC pulls this year. Will have to try again next year. It's at least 200 miles to the closest one though.

I'm with you, I prefer the 5-6MPH 10-20% RPM type classes. Lets you run a little, but doesn't take big $$$ to play. 12MPH becomes a money war. Might be fun to hear the B zing along at 2500 RPM's though - but there just aren't that many people around here that pull those classes and to rebuild it just so I can run RPM's to pull against myself or one or 2 other people - not for me...

Probably not much hope of getting an intermediate class added though, there are already 30+ classes. Would be fun to see a 15% over RPM, Cut tire, 5-6MPH. Too big of a jump between stock and super classes.

-- Stock -- 10% RPM, 3.5MPH, small tires, topcuts only
-- Super -- 2500 or 3000RPM, 12MPH, no tire size, full cuts

 

[Molinesam]

jd b, Just thinking, but a 5 or 7.5 mph class would draw pullers from other classes, with the total hooks remaining the same. The closest pull to us with these classes that I know is OTTPA in NC. Enjoy pulling their 5500#,6500# 5 mph & 6200# 7.5 mph 2500 rpm with an M.
Maybe you can make it down our way next year.
www.edmundantiquetractorpull.com
Thanks, Sam