The bigger you go, the shorter the lifespan will be. This will be true for both stroke and camshaft specs. If you're dead set on a 427 block, go iron and keep the bore to no bigger than 4.25. Then stroke it with a 4.25 crank, Get a good set of heads but keep the cam specs down within reason (no more than say .550 lift and the duration @.050 around 220*. Also go with a hydraulic lifter grind, roller would be even better. The bigger you go on cam specs, the higher the powerband will climb.

 

I can give you things to think about so long as you consult a very experienced FE guy for the finer details.

- Bore/Stroke: Sounds like you're asking if over/under square is better. I don't think that matters for this build.
- Block: Aluminum is okay though more expensive than iron. In a 427, it's likely easier to get since only one company is making iron 427's. Remember, these are limited production and unlike the big runs for mass produced cars they often have kinks to work out. Not trying to talk you out of aluminum, just know it can be a little more finicky to deal with as well as more expensive.
- Bore: Might as well stay with 4.25. Boring it doesn't gain a ton of cubes. If you end up stroking your 360, I'm for saving the bore and only removing enough metal to clean it up. I don't see the need in boring it to the max since that makes it the last time for a rebuild.
- Cranks: Scat is well known for quality in terms of fit and durability. Available in 3.98, 4.125, and 4.25 strokes. RPM cranks are good too but often need a little massage to fit and come in 4.375 stroke. However, the 4.375 stroke will take a little care in making sure there's no interference in the block and I think the piston pins have to go through the rings so most people stop at 4.25 stroke. There's really no reason to go with less stroke than a 4.25.
- Pistons: Going with forged pistons gives you the option of custom sizes. Main benefit of custom size is ability to dial in the bore size and compression ratio you want. My truck is at 9.7 and run 91 gas but can run 87 if I want.
- Cam: I went with a hydraulic roller cam. Hydraulic flat is okay though there's a chance of wiping a cam if you're not careful and they need special oil. You won't likely spin the rpms to need a solid roller or solid flat cam. Just remember to make sure your distributor has a gear that's compatible with your cam (i.e. steel goes with steel and cast iron goes with cast iron). For cam specs, not much need to go higher than say 0.550 to 0.565valve lift for your purpose. Selection will benefit greatly from consulting with an experienced builder who can look at your over all build to select a cam or get a custom grind.
- Heads: Several after market choices...edelbrock, BBM, survival are all good
- Intake: Edelbrock RPM will do nicely for your purpose. It will likely need a machinist to cut it to fit so you don't have leaks.
- Rocker arms: I went with aluminum T&D but if I had it to do over might have went with factory styled non-adjustable steel. They'll last forever and there's nothing (no adjusting screw or needle bearings) to ever fall out.
- Distributor: I went with pertronix mainly due to its adjustability though there's other good choices out there. For a truck I like having vacuum advance as well (for stronger idle and a bump in mpg). If you're going to race then vacuum is not necessary.

- Flywheel: Not part of the engine but I recommend getting a steel flywheel. Hate to have a cast iron go ka-powie on you right next to your feet.

- Your 360/390 block will be plenty but I get it...a 427 is dang cool and you can always put it in something else...another truck like for truck pulls or cam swap to make a racer. All of the components I mentioned above will work in a 427 or 360/390 block. Of course, the 427 will use bigger pistons and bigger cam.

 

I'm not going to get into the engine build discussion, I have a stock stroke 406 that's going in my Fairlane for a cruiser.
I can tell you that top loader 3 spd isn't going to cut it behind a big hp high tq engine, I busted them behind a good high winding 289, broke one with a stock 390 2v.
You start ripping thru the gears on that wide ratio trans and it'll break.

 

Not that I'm a fan of the 3 speed Toploaders when better transmissions are available, but you're the first I've heard that broke one. My 67 GT390 Stang came with one from Ford and the year or so I hammered on it before finding a 4 speed, it never gave me problems.

 

I blew a couple bad enough the split the cases in a 64 Fairlane with a mild built 289 shifting at 7000 rpm, that car hooked really good, may have been part of the reason.
390 2v was in a pickup loaded, came off the clutch pretty fast and broke a tooth off 2nd gear.
The top loader 3 spd was built much like the top loader 4 spds but I broke a couple of those as well, standard models, not the big shaft units.

 

Having a aluminum Pond block, I can tell you that the only issue I found is that if you use a solid roller cam, the aluminum grows quite a lot. I set my exhaust lash cold at .005 and they grow to .022 when normal running temperature. Torquing the heads frequently is needed. I purchased a aluminum block because of weight for our drag car.
For a daily driver, I would use cast, with a hydraulic roller cam., out of the box Edelbrock rpm heads, mild cam specs, 4.375 stroke, 4.25 bore, Edelbrock dual plane intake, #7105.A quality set of headers, 750cfm carb or if possible, a fuel injection setup. That would make a killer pickup engine. It would not be cheap, but we only live once on this earth, might as well enjoy this one.

 

The 64 would have been the weaker one same as the 4 speeds.

 

64 Fairlane, 65 289, 67 and 68 transmissions
Truck was a 70 with a 390 2v from a 69 Galixie, trucks original 3 spd
4 spd was in a 390 4 spd 67 Cougar GT.

 

Lotta good points I haven't thought about fokes never head anything bad about the old 3 speeds till now.

 

Lotta good points I haven't thought about fokes never head anything bad about the old 3 speeds till now. Same I'm also supprised to hear suggestions to stick with iron. If I was going to stick with iron I'm probably going to keep this block long as I can. But for a limitless budget block to slide in its place. A socks bore and stroke 427 with modern heads and intake world easily be more then that stock 3 speed trany can handle. Is their any way to beef it up? I'm sure stronger clutches can be found and if money is available stronger gears made?

 

The 3 speed's life depends on how you treat it. Subject any transmission to high revving clutch dumping and none will last. Those old toploader three speeds were among the best you could find. They were even put into GM cars as well. Don't let anyone scare you on this. Treat it right and it'll be fine. I've been running these things for 40 years and have yet to break one due to abusing them. Only Toploader 4 speeds I broke happened when I used the wrong bellhousing and left the input shaft unsupported. I ran a small block Toploader behind a stroker LowRiser 427 (454 with a 428 crank) and never had a problem. Now the guy I sold the 67 Stang with that engine to, did break it after trying to drag race it at a local track with a 2.50 geared 9" rear with Trac-Loc. He first put a set ot M/T slicks on it, then burned the clutch up. So he replaced the clutch with a button clutch. Next he tried to launch it at 5 grand and broke both the 9" rear and the Toploader when it hooked up. It's all about how you use it or abuse it.

 

These FE tend to be kind of on the expensive side but you can make it reasonably mild and dependable. I have a aftermarket iron 427 block with 4.25 stroker crank not in a truck but in my street '69 Mustang. It has 11.2:1 compression with aluminum heads. The cam isn't very big and I have a loose converter with a C4 so it's pretty well behaved on the street. Never had it on a dyno but finally got to take it to the track last month before the local drag strip closed. The car ran much quicker than I figured it would so I had too much gearing so couldn't make a full 1/4 mile pass without hitting the rev limiter so just ran it for the 1/8 mile time and speed which was 6.76 sec at 101 MPH. I think that converts to about a 10.60 quarter mile pass. Using a horsepower calculator, the engine puts out about 550 horsepower. It would have been a couple tenths quicker at a low elevation track. If you put this engine in a heavy truck it would still be pretty quick depending on the weight.

 

A $20000 engine and a $50 transmission. Golly.

 

Main performance benefit of aluminum is lighter weight. Aluminum blocks will tend to make a few percent less hp than the equivalent iron block build.

Not sure if a top loader can be beefed. Something like an NP435 will handle the power if you avoid hard/fast shifts. TKO will handle the power as well.

 

Had a 3 speed in my 57 Fairlane with a mild 312 Y block. Went thru 13 of them in 2 years. Wrecking yard was giving me special pricing. lol