IH Scout Build

SoontobeLifted_72

Well-Known Member
Joined
Nov 11, 2007
Location
Wilmington NC
Im building a 1972 Scout II that Im planning on using primarily as a toy. SOA, 37s, 4.56, Dana 44 front and rear, 345 V8 with DUI unit and mild cam, around ~600 to 650 cfm carb.

Now my question is what size fuel line should I use. Im thinking 1/4 or 3/8 but Im not really sure. Any input is appreciated
 
From what I've read, 600+ cfm carb on a 345 is going to be too big unless you're planning to do a considerable amount of custom head work. 500 cfm should be plenty.

Check this link http://www.csgnetwork.com/cfmcalc.html. Safe continuous operating rpm for a stock 345 is ~3300 rpm. It looks like 350 cfm would be adequate. You'd have to hit 6000 rpm to need 500 cfm, way too high for that engine IMO.

Unless you're building a "race" IH engine, the stock sized fuel line should be plenty large.

There are many threads on www.binderbulletin.org about building IH engines for more power. Plan to spend some serious dough, $3k+ on a rebuild/upgrade, if you're going that route.

One other comment - 37s with D44s on a heavy pig like a scout is a bad combo, particularly with lockers. However, if you're only thrashing through mud pits with open diffs or going to the truck show, go for it!

Not trying to rain on your parade, just trying to share what I've read.

BTW, are you running a 2 or 4 barrel?
 
4 brrl spread bore. The motor is going to be bored to .30 with aluminum an manifold and yes the axles are open. Not planning on any rock crawling here in Wilm! Like I said any input is welcome and appreciated so post bluntly. This is my first complete rebuild so Im definitley still learning. I also have been on Binderbulletin for a while doin research and asking questions. BTW thanks for the link.
 
Fuel line size is one of the few fuel related items that too big wont hurt you. You cant be too big. 3/8" is plenty. 1/4" may starve it at higher rpm. (Which for my last corn binder was anything over 3000 rpm!:driver:)
 
I am running a 60 and a 14 bolt under mine with 38's. - before going to the 60 I was running a 10 bolt eight lug. under mild wheeling I was braking every time I went out. I am now running fuel injection. I was running a edelbrock 750 cfm carb with a cam swap, chevy BB valve springs, some porting in the heads and intake with headers. I worked well the Edelbrock carb is highly tunable with the tuning kit. 3/8 fuel line is what i would use ( better safe than sorry).
 
I actually think you'll be ok with the dana 44's if you arent too hard on them, but since you are doing a soa go ahead and put an axle wrap bar on there for that size tire cause the torque will twist it and you can snap the u joint or the ears off of the driveshaft.
If you are worried about breaking them then just build them up as you break them with chromoly shafts. i used the holley truck avenger on my 392 and it works great and 600-650 cfm will be way too much in my opinion. As far as fuel line goes i wouldn't touch it unless it needs replacing. Also good luck with the build and post pics of it.
 
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