How big of a project is it to switch from a 5.8 to a 460 in my 1989 F250 two wheel drive..Or should i just update the 5.8..It runs well... Thanks

 

My last F-250 was a 2WD with the 351HO engine. It performed very closely to my 4WD F250 with the 460.

You would notice the 460's performance when towing a heavy trailer, but otherwise the 351 works well. If I had the choice, I would keep the 351 and perhaps change the rear end gearing to match the type of driving that the vehicle nomally sees. With 4.11 gears a 351 powered F-250 is quite a performer.

Lou Braun

 

It wouldn't be as easy to swap the 460 vs rebuilding the 351....the 351 can easily make more power to match or beat a stock 460...but you'd have to replace the transmission with one that'll fit a 460...and the 460 is going to need all different parts like water pump, accessory brackets, fuel rails..etc etc...it just drives the cost up.

 

unless you are pulling alot of weight stick to your 5.8 liter have one with 5 speed 4x4 ext cab still can pull16000- lbs all day has 259000 miles going strong ,but does not conpare to my 7.3 auto 4x4 ext cab .

 

A descent performance rebuild on the 351 + exhaust will be much cheaper than a 460 swap, provided the 351 rebuild doesn't involve a stroker crank, supercharger, or turbo. I looked into doing a stroker 351 (408"), but decided the cost was beyond reasonable for me. From the numbers I looked at, a mildly built 460 and trans could be swapped for close to what a high performance stroker small-block would cost. Which one would perform better depends on what you want to do with the truck. For towing, I'd take the big-block over the small-block: more torque at lower rpms.

 

Um....my 393 was only a couple hundred more than a 351.

 

Justin, because of the year of my 351 ('92 in an F350), wouldn't I have the added cost of changing to MAF from Speed Density to do anything real high performance with the cam and heads?

In addition to the stroker crank, I would also want to port the heads, put an aftermarket upper and lower intake and port the lower to match the heads, cam, headers, and complete exhaust including high-flow cat and y-pipe, in addition to the bottom end work to make it a stroker. With either a big block or a stroker small block, I'll still want to build my transmission, even though the big block build would cost more 'cause I'd have to swap the case.

How much do you estimate all that would cost?

My own estimations are pretty high, partly based on parts pricing I did and also on what it cost my buddy to build a 383 Chevy stroker with 1.94 heads for his pickup. He spent about $4500 on just the motor.

Chevys are usually cheaper to build than Fords and his doesn't have any electronics on it either except an HEI dist. He went big on the bottom end, used a brand new forged steel crank ($$) and expensive rods too. On the top he did a roller cam and roller rockers and ported the heads and intake. The motor really screams . I'd like to build my 351 like that, but I cringe to think what all that would cost on a Ford .

Considering what I do with my truck though, I'm still thinking a big block is really the way to go.

I'm estimating I could find a complete 460 and do a mild rebuild on it for $3500, spend another $1000 on a C6 with a big-block case, a HD converter, clutches and a shift kit, and another $1000 on headers and complete exhaust and come out not too much more than stroking and hi-po'ing the 351, building the C6 I have now, and still spend the same Grand on the complete exhaust.

My friend's stroker engine is quite strong, but the powerband is still higher up in the rpm range than most big blocks and I still think a mildly built big block would put out more torque overall, especially down low, which is better for towing. I use my truck to pull a trailer and haul a camper and don't have much use for alot of high-rpm power as I rarely run my engine above 3500 rpms, even with 4.56 gears and no overdrive.

In 3rd gear at 65mph it spins about 3200 rpm and in 2nd gear at 45mph it also spins about 3200. I usually cruise around 55 mph, sometimes 60, to save gas. Anything above 65 mph and it starts sucking up alot of gas. Pulling a steep grade, I might run 2nd gear up to 50 mph on occasion, which would be about 3600 rpm and taking off from as stop when loaded I might run 1st gear up to 35 mph on rare occasion too, which is about 4200 rpms, but I don't keep it there for very long. My truck seems to shift at about 25 mph and 40 mph pulling on fairly flat ground (about 3000 rpm). This 351 really dogs below 2500 and seems to like to run around 2800-3000. From the info I have about it, the torque peak is at 2800 and the HP peaks at 4200.

Power in my friend's 383 seems like it doesn't come on strong untill about 3500 and up. Maybe his cam is too big but I remember my 454 dually with TH400, 4.10's and stock tires used to pull plenty strong from 2500 and up. I rarely ran it above 3500. He's running a TH350 with 4.56's and 36's in his truck. He should have enough gear to pull the 36's with his stroker as 36's with 4.56's is about the same as 4.10's with stock tires, but seems to have to run it up into the rpms more than I would like to with mine.

My truck has 33's on it with a C6 and 4.56's. That's plenty of gear for my stock 351 and 33's. I'm thinking I should probably go up to 35's with a big block to raise the gearing a little to match it's powerband better, but I would wait on that to see how the motor does with the gearing it has now first.

Anyways I'm just rambling, thinking of ways to blow a bunch of money I guess . If you have any thoughts on it, I'm open to anything...

[On edit: I guess this a little post hi-jacking, sorry. It is related to the original question though...]