Thank you for all your input, there is a lot of good information to digest. I’m just interested to know why strokers have the reputation for being unreliable, obviously piston speed increases, creating a little more wear, but are there any other down sides? Thanks

 

Any increase in power increases wear to some degree. Some tactics or methods more than others. If you shovel is not a absolute cherry original survivor… have at it. Even if that 40,000mile top end turns into 30,000…. Who cares because you’ve had a hundred times more fun watching Twinkie guys foam at the mouth mumbling something about your beating them being impossible because their valve geometry is better

 

The longer the stroke and larger displacement causes more of an up and down movement of the engine itself and when bolted to the frame of course that transfers into the bike more. My handlebars on my 96" EVO and my fairing do a dance at idle as well as my left saddle bag. The cam probably has something to do with that too. Not a downside unless it bothers you. They say a 61" knuckle is smoother than a 74 for the same reasons.

 

"My handlebars on my 96" EVO and my fairing do a dance at idle as well as my left saddle bag" ... My 1992 FLHTCU was the same way ... So is the 2009 FLHTCU ... My Shovel dances to its own tune ":>)

 

So this was to stroke or not… however we’re getting into bore vs stroke. I have strong un-popular opinions on that and have paid my dues to have that opinion. IN SHOVEL CONTEXT or maybe HEMI context.. they respond to stroke better than bore. Cubic inch isn’t cubic inch.

For example a 88” 4 3/4” stroke motor vs a 88” 4 1/4” stroke with the exact same mechanical compression and cam… same pipes. The 4 3/4 stroke small bore will make a broader torque curve and spank the bore engine 7 ways to Sunday. Don’t care what a dyno or head Porter says. I’ve seen it up close and personal more than once.

Joe Smith aside cause we ain’t talking nitro… a 102 3 13/16 bore will get spanked consistently by the 5” stroke 3 5/8 bore motor.

My theory (that means a guess based on what I’ve seen and built) is poor flowing high turbulent shovel heads can’t take advantage of the short stroke big bore as much as the swept volume of the stroked motor.

Where guys really fail making shovels fast is they forget lore and legend and start thinking science r&d done on modern motors.. these ain’t rice rockets or formula 1 15,000 rpm motors. These are big tough tractors and they don’t like rpm. You wanna go fast go back to what everyone says we’ve grown past.. listen to some Beach Boy songs. The old HotRod ways worked with the old hotrods. Big obnoxious cams, lots of compression and cubes make old motors rock. Rpm and science is for new engines.
A legend with street bike Shovels was Mike Magaro. Here’s a guy that had a stock looking all the weight there FXE, kick start, 130 street tire… he ran 10.50’s consistantly with his 103. So he finally went to a 114… guess how fast? The same, 10.50’s. The heads didn’t care how much more compression or cubes you gave it. It was done. They simply no matter what welding, shaping or head Porter couldn’t get past the 10.50’s. The bore didn’t help even adding that many cubes.

 

You nailed it, Hemis are old school and need old school tuning, long legs and a shitload of torque is what you need to tune for. My stroked C3 Corvette had all of that and was insane, unlike a high-revving modern motor, it didn't need to rev to produce power and had instant torque off the line...Shovels are no different and that is why I ride one.

 

an 86” built as you describe is probably going to make about 60 - 65 horsepower. Not bad compared to stock, that’s probably a 10 horsepower gain. Take that compression to 10:1 with say a 4050 V-Thunder cam and the same motor would likely jump to 80 horsepower.

Take it to 10.5:1 with a Redshift 580S and your 80-85hp, 11.5:1 with an M grind and your 85-90hp.

I’ll see if I can find an old dyno sheet of a 84” I built that I’m really proud of. I built it for someone else but I was pleased.. it was 10.7:1 with a redshift 580s. I pulled out all the stops and set the heads up, ported them, did every trick I knew of and it made like 90 ft lbs and 88 hp and had a super flat, wide torque curve.

It was a 1974 motor. I used T&O 4.5 stroke wheels, shaved and balanced at 60. Stock jugs 20 over. sifton lifters and blocks. I even remember spring seat was at 180. I had the valves sunk 15 thou with new seats, crane roller rockers. I cleaned up a little around the valve guid and at the turn of the floor for a little of that classic “D” shape port. The intake I blended with the heads and we ran a stock G carb on it. Pipes were 36” long equal length drag pipes with thumb screws. It was a crane Hi-4 ignition. It was a super clean nice motor to start with.. no heli coils or core shifted heads. It was nice and straight.

why can I remember in detail someone else’s motor I did over 20 years ago but have no clue what I had for dinner Friday night?

If these numbers seem low… they are actually really good numbers set aside all the bloviating “the fish was this big”… Shovels make it a lot harder to make the magical 1.2 hp per cubic inch. An EVO has some sweet spots were you throw a high flow air cleaner and pipes at it and you see a 3-5 hp gain on a stock motor… That on a shovel and your lucky to see any change. I stand behind a shovel makes the same power per cube.. but it’s a lot harder to do. COMPRESSION is extremely important. For a Hemi to make power it MUST have compression. And 9:1 is nothing.

 

Do you remember what trans and gear ratios you used?

 

That build wasn’t my own… I built the motor. I did help him install and tune it, but I don’t recall. Defiantly the stock 74 tranny. But I don’t remember the gearing or if it was changed. It was probably a 23 tranny, 51 rear. If he asked me I would have told him to run 23 tranny and 48 rear for his broad torque curve.

 

I read through this thread first before adding my 2˘.

My first shovel, a 1979 74” FXEF I put well over 40,000 on it and modded quite a bit to improve ride ability on modern highways and a bit more power. That old bike is no match for what my ‘76 FXE is.

My current shovel build: 84” S&S balanced assembly, 450 S cam, .20 over forged S&S pistons, S&S Super E carb. Dyna 2000i ignition…stock brakes, oiling - lots of obvious original bits.

Had this built for durability AND more power. Keeping my expectations real I was Not out to prove anything to Evo’s - Twinkies or whatever.
The seat of the pants dyno says I’ve got over 70hp and at least 80-84 lb-ft torque. This started as a tired 1978 1/2 80” in a 1976 FXE. The gearing is stock and the trans is an FLH ratchet top. It’s not an interstate highway cruiser, but is a FUN backroads blaster.

The torque is endless pulling from 1500-4500 rpm. By shifting 3000-3500 rpm I’ve got all I need for big grins and squirting along. Shifting with all that torque means I don’t have to see much more than 2000 rpm to scoot away smoothly. Friends who followed me on twinkies said “I thought you were taking it easy on that old…” Funny thing is I was being easy, it just runs so well that quickly getting up to the posted speed + is damn entertaining. S&S did post power numbers for this build - somewhere - I’m definitely “there”.

This 84” shovel is way smoother than my 74”, rides and handles better - but it was completely torn down and rebuilt with care. In every way it delivers what I was out for. There are no glitches in the power delivery - linear - hard pulling.

The cons if any are I spent enough money doing the entire bike to buy a brand new entry level big twin. I kinda figured I’d be at that going in. If you are just rebuilding the engine your costs will be reasonable and the improvements should bring a big smile when you twist the throttle.

I’ve now got 2600 miles on this and no regrets.
S&S makes proven combos for the shovel.

Ride safe!

Stopping by the Barkhamstead reservoir for a nice pic.