Maxium torque 250

[Anonymous]

I know that the 250 will not make a ton of torque but if built right should be enough.

300 is great and too big for a scout

Smaller cam the better
more valve lift
more compression (low enough for premium 91 pump gas)
more advanced timing
wider lobe center
longer headers
better breathing intake.
less cfm
_____________________
more cylinder pressure


i understand that the 250 is good for 240 lbs of torque
is this correct

 

[ASMART]

Smaller cam the better
dont go smaller than stock
more valve lift
Yep
more compression (low enough for premium 91 pump gas)
Yep
more advanced timing
Yep
wider lobe center
I think thats right
longer headers
Yep and smaller tubes
better breathing intake.
Yep to a point. ports can get to big and cause air flow to slow
down. This makes the fuel drop out at lower rpm. Not much of chance that would happen with a log intake

less cfm

More is better until you get so big the air and fuel is not mixing properly at low rpm due to low manifold vacuum. I would not go above 500 cfm(2bbl measurement) on the 250 if all you want is torque. You probably can't spin it fast enough to need more flow any way.

 

[Anonymous]

what is the max vasve lift the 250 can handle without flooding out at low revs?

 

[Anonymous]

vasv lift=valve lift

 

[Anonymous]

I know that the 250 will not make a ton of torque but if built right should be enough.

I dont know...but 190 ft lbs at 1600 RPM stock seems like a fair amount of torque to me...everyone i talk to seems impressed by those figgures, and then they ask why i cant do a burnout...then i tell them the weight of my car....although i would like about 125 hp and like 250 ft lbs torque...that would be enough for me and shouldnt be too hard to get.

 

[wsa111]

Huntersbo, i beleive a tighter camshaft lobe center will give you more low end & midrange torque, since you are closing the intake valve sooner which will give you more low end torque. The negitive factor is the rougher idle with a 108 or a 110 lobe center camshaft. Just don,t go too high on the duration & you should be ok. Also for more torque degree the camshaft more advanced. Check with your camshaft supplier & get a second opinion. William

 

[ASMART]

The rough idle is a function of the time when the intake and exhaust is open at the same time. Basically, the less overlap of both valves being open usually means more torque in the lower rev ranges. The lift you can get depends on to things. 1, How much actual space there is for the valve to go down and 2 the ability of the valve lifter to follow the cam ramp with the assistance of the valve spring without floating the vaalves. The more lift you have at shorter durations the faster the lift occurs. This causes the valves to "float." It means the valve train temporarily loses control of the valve because the spring cant keep the lifter on the cam.

 

[xctasy]

Every Aussie Falcon engine, from 1971 to date, has more than 190 lb-ft at 1600 rpm, peice of cake! The later cross flows have over 200 lb-ft at 1600 rpm.

A 1-bbl XD to 2-bbl XF carby 250 will do it from the factory, still on a 110 degree lobe centre.

I'd be supprised if a US 250 couldn't match that with the 78 on log head and just a 32/36 Weber and some bigger 30 and 31 mm venturis. Stock Aussie 1-bbls had tiny carbs,while the 2-bbl Weber 34 had 29 mm chokes and was able to pull 2.54:1 diff ratios from the factory with a 3-speed automatic and 25 inch tires.

 

[Anonymous]

thanks alot

 

[Anonymous]

I recieved this from isky:

Hi Hunter,

The smaller the better.

106-108 is best.

Thank You - Nolan/Isky Racing Cams

 

[Anonymous]

106-108 lobe centers are best acording to isky