K so I have a 97 f350 that has a 460 with about 130,000 on it. I also have a 91 f350 with a 351w in it, with a rebuilt tranny, both at about 20,000 on them. The 460 gets like 8-10mpg because of an exhaust manifold leak and the 351 gets like... 15mpg. I wanted to do a swap because I want better gas mileage in my 97. It's my show truck and my daily driver... Will they be good for a direct swap, or do i have to do alot of modifications?

I also want to install a K&N cold air intake on both of them. Will it all work or is it not worth it.

 

You're looking at a powertrian swap not just motors because these two don't share belhousing bolt patterns. And unless both trucks have the same gearing and tire sizes you won't get the same fuel milage after the swap. What transmission are in these trucks anyway?

 

Both have the E4OD. I am not worried about swapping transmissions either, I want to swap those aswell.

I believe they have the same gears, I'm not very familiar with that stuff. I know they both have DANA 60 axles. And the 91 had 35" tires on it, ran great gas mileage, but I'm gonna go to 33 or 34" tires on the 97.

 

you have to swap the tranny with the motor period. no choice there.

give it hell and let us know how it goes.

 

My ? is Y i have a79 sno fighter with 74 460 out of a gran marquise 780 holley t-19 205 twin D60's 2 1/2" duals 77 truck manifolds ambalance oil cooler n I get right around 14 to 15 mpg granted thats at 55 mph but im n no hurry were im going will b there wen i get there LOL!! lov this site.Jus seems like alot a work to me n u wont have the THRUST that only a big block can give ya NO substitute 4 cubic inches!

 

Wiring is gonna be an issue. I just swapped a 1990 460 into my 94 351w. They have different connections on the wiring harness, between the eng and the body.
Of course you know the trans. has to be traded too, and the motor mounts.
The bigger tires would give you better mileage in theory due to a higher gear ratio, axle turns less to go the same distance.