crossflow carbs

[ultrafast]

Is there any improvement or issues using the 1- 3/8 carbs from a early 235 over the 1-5/16 carbs on a modified v4 crossflow. looking for input from someone who has done this.

[Freddie Webb]

Yes I have used those and the land and sea big bores. There is a gain there.

[EMDSAPMGR]

The larger carbs will flow more air and fuel. Some of the early 140 hp V4 crossflows used these 1 3/8" carbs. Depends on what engine you are using them on. If it's a low hp block with small ports, you may not see much difference. Possible the holeshot will suffer, but top end/WOT should improve. Keep in mind that while the carbs will bolt on, the butterfly shafts are not the same length between V4 and V6 crossflows. The V4 shafts protrude about 1 3/8" from the side of the upper carb body. The V6 shafts protrude only 3/4". Those shafts would have to be changed-a delicate procedure that my involve stripping the butterfly screws.

[JWTjr.]

The 78 and 79 140s used 1-3/8" bore carbs. I have swapped back and forth with these on several 140s both modified and stock. The bottom end and lower midrange punch suffered with the larger carbs. Top end on a JP boat improved by 1 mph.

[Umassot50]

I've put on the 1.375 carbs. They work good,but like was said you have to screw with the throttle and choke shafts. If I did it again I would ditch the flapper chokes and install squirt primers. This was done on a 73 135 HP with the good heads. I put on a 77 115 intake which has better flowfrom carbs into reed cages. Used boyesen reeds. It eventually melted a piston. I would jet up and run some 100 aviation mixed in if I did it again. The 73 heads were pushing 165 psi on gage.

[ultrafast]

Thanks guys I will probably stick with the 1 5/16 carb
plan to run 140 head very lite boat