Port the ehxuast side of those D3's. Work the short turn real well, widen and smooth the port roof as well. Grind the smog bump down into a smooth vane pointing directly out of the exhaust port. Smooth and deepen the trench around the valve guide. Beware of the trench of the right hand side with chamber up and looking through exhaust port, there is water pretty close on the right side.

Run a Lunati 61601 cam with an Edelbrock Performer (not RPM) manifold. For towing and your modest HP goals any more intake than that (such as the air gap and Stealth that others have recommended) and you'll be leaving power on the table down low.

For pistons, if you zero deck the block (you should for towing, to prevent predetonation quench of .040"-.060" max) you would want a 9:1 or slightly higher compression ratio so you would ideally be looking for around a 12cc dish piston.

If you don't run headers there's not much point to any of this. Stock logs are performance killers and all your port work on the heads will have been in vain.

 

Well guys, just got back from over a 2200 mile round trip out to MO & ol motorhome did right well.

Last year, same route & milage, but more weight than this year, went out on 8 cylinders came home on 6.
This trip, weight was a little less at 23,280lbs down from 23,860.

Some noted things about this trip, one hill close to my house that normally pulls the engine down & into passing gear when climbing, which is lower than 45 mph, this trip I hit the hill at 65 mph with cruse on but pressed the gas pedal W/O. About 3/4 way up it dropped to 55, but then climbed back up to 65. Needless to say I was well pleased with the engine work done after seeing that.

Nothing has been done to the bottom part of the engine other than a pick up tube replacement, has over 70,000 on it & holds 60 to 70 psi oil presure.
Heads have had Stellite seats installed & valve are stock Ford what ever came in the heads & 1.65.
I did port the exhaust side while the heads were off, opening them up quite a bit & smoothing out the flow, but didnt go to wild for fear of hitting water. These heads are E6TEs with the air hole & left as is with the hole not filled in.
Cam is the Summit brand #3500 with 484 lift intake & 509 exhaust good for 1500 to 4500 rpm. Timming set was the Edelbrock double roller & set at 4* advance not straight up.
Stock dizzy as is & nothing changed, YET but will be soon.
Stock exhaust manifolds with 2.5 pipe off each side into a Y & then up to a 3.5 single pipe to a diesel muffler. Only have 3" from the muffler to the tip & it dont seam to be effecting performance. Has a bit of rumble out the pipe tip & you can hear its louder going down the road than when the ol stock exhaust was on.

Ran this whole trip with the EGR unhooked & dizzy getting vacumme from the main port on the intake & then through the heat switch on the water neck.
4150 carb, nothing done to it, but I can tell the engine needs more, but wondering what to go to.
All in all, over the whole trip, the engine performed real well power wise. Other than the steep hills in MO state, out on the open road it never dropped below 55 mph on cruse climbing any of the grades.
Engine used 3 qts of oil out & back, but I'm not so sure if it didnt leak out instead of being burned because shes a bit oily on the underside. I'll be checking into that today, see where its comming out from.
Route we took was down I-85 to Atlanta, I-20 over to Birmingham, 78 up through Miss to Memphis & then 63 across Ark into MO.
Neil

 

did you do the port work yourself or did you ahve a shop do it?

 

I have to agree on the manifolds power killers. On the camshaft stuff I live in higher elevations and couldn't get my engine to perform like I wanted with a hyd cam and then went to a solid cam. Ran the hi energy stuff again and the extreme cam 4x4 stuff and ran another brand might have been a lunati. Later went to a comp solid 270 then had one custom built for my towing motor by mpgheads. My truck now runs like I think it should. I still want more but thats just the way it is. This motor never turns over 5500 rpm. The performer intake rpm manifold ran OK but the air gap ran better overall than the other intakes in cold and hot weather. Never ran the performer on my 472 so can't speak on that intake. My towing is in extreme hill pullin situation and 9% grades are hard on truck and keeping the temps down is another situation also. A good windage tray/crankscraper helps keep the oil undercontrol also. I"ve heard up 20 hrsp free'd up in the upper rpm's and normally around 10 hrspwr over all and keep the air out of the oil to keep oil temps down. Things to consider in a build and my idea of a tow motor is probably a little different than most but these are things to consider.

 

Did it myself, just to the exhaust side though.
I do 2 stroke performance cylinder porting, so its like an everyday thing for me. Those 460 heads were just on a bigger scale than what I normaly work on.
Next set I do, I'll cut a little more out for more flow, but heed the warning about the right side & not cut to much there.
Neil

 

C-Leigh racing, what kind of MPG's did you get on your trip?

 

Before any work had been done to the engine, right after we bought the M/H, was getting around 4.3 normaly with the Onan gen running to operate the roof air units going down the road.

First trip out after the first head pull & repair, got around 5.5 average & one tank full got 6 flat, but the heads didnt last but about 1500 miles before the seats started beating out.

This second head pull, repair & cam install, averaging 5.6 so far.
I guess after reading a bunch of other post, what I'm asking the 460 I have, to do, is a lot more than most on here are asking of their engine.
You take a 36' motorhome & hook a 24' enclosed behind it, that ol engines got a big big job to do.
Shucks, I'm over 12,800lbs on the drive axle & trailer is 5800lbs, so I go down the road & got to drag that weight + push the wind out of the way.

From my experience with pulling the heads & having them repaired, what I learned, who ever is going to do the repairs to them, they need to know just any regular type of replace/repair wont work, maybe for a car or a plain jane pickup truck, but not for a high weight pulling 460 engine.

You not knowing & that repair shop not knowing, in the end will end up costing you.
My deal was, I didnt know because I had never had anything this big with a 460 engine or what it would take to keep it alive. I only wish that I had found this site & 460.com alot sooner & then I may have known a bit more about what I was dealing with.
Neil

 

just wanted to let you guys know I'm almost finished with the build. The Long block is assembled. I ended up boring it .30 over, Compression should be around 8.9:1. The heads have had a valve job and new valves and springs, The exhaust side has been ported. I'm running a Edelbrock performer manifold and 1411 carb. stock dizzy(want to get recurved). A little bit bigger cam but nothing wild. I'm bolting on all the tin and bringing it home on Thursday. I need to paint it.... pictures soon.

 

Keep us informed. I want to know because I'm getting ready to do the same project.

 

Ok, now what did you have installed for exhaust seats, ??? you didnt just take the machine shops word what they did to them did you.
If they surfaced seated the seats in those heads, they could have cut through the induction harding Ford did to the heads in the seat area & into the plain cast iron, because its not very deep & you'll end up back in that engine again with valve problems.
Stellite or Carbide type exhaust seats installed are the only type will stand up to the punishment from that high heat.

Just letting you know, been on two more trips, one to north west PA & back & one 300 mile, so around another 1500 miles & no problems. Looks like the Stellite seats are holding up.
Still pleased with the power output, except for the time it cut off right smack dab on the PA turnpike around Pittsburg about 7:00am. Sweating bullits only to find the green wire came loose from the coil. Thank you God.
Neil

 

In realized I never posted pictures on this....

 

Looking good there special, something about everything looking fresh & new.

It has been awhile since I been on, close to three years & sadly, we were on a short trip & broke down.
Engine lost oil pressure so we had to be towed & the wrecker lost it, turned the m/h over & totaled it.
Family & myself were in the wrecker & nobody was hurt, but it was a twilite zone movie for a few minutes.

Last time I worked on the head, shop that did the work screwed me. One of the seats they installed they cut through the head & into the water jacket. One trip & it went to smoking white out the tail pipe so kissed those ported heads good by.
Next set I put on before the break down, ported them a little more & this time I got Carbide exhaust valves from Tucker Valve Seats, no problem with the heads, then the crash, but that ol girl could run with the big trucks. On rolling highway, I was running half throttle.

We have a newer model M/H now, still a Ford with F53 chassis & V10 6.8, 4R100 trans & drive train has been trouble free for 28000 miles.
Neil