Will a 93" dual plugged shovelhead going to a rivera 6-speed tranny outrun one of these new 96" twin cams?

Question

I have an 1981 FXWG with running a 93" hot set up from S&S. I also went ahead and ordered dual-plugged heads and a Rivera 6-speed tranny. I really want to outrun these new twin cams both out of the hole and on the high end. The tech working on the bike is very reputable, however it will still be 2 months before the build is complete. So I still have time to throw in more stuff.

Anymore suggestions towards the performance of my bike? Or will that be enough.

p.s. the bike is a daily rider, so I want it to last as long as possible

Answer 1

you will have no problem beating a STOCK one in a drag race, or a roll on unless your overdrive is geard too high.
keep in mind there are very few stock ones over 2 years old & when they git rid of those ridiculous epa cams that open the valves slowly to keep the noise down their a whole different motor.
heres some hints, use james metal base gaskets, use solid copper head gaskets sprayed with permatex copper sealant,you will have more torque at low rpm with 1 3/4 pipes instead of 2 inch for the first 12 to 16 inches, step up to 1 7/8 & 2'' after that , you might want to experiment with torque cones to get the power to come on before 80 mph in 6th, crane dual plug single fire ignitions work pretty good with shovels,set the rev limiter at about 5500 with your 4 1/2'' stroke for reasonable ring life, if you dont have roller rockers select a cam with about 1/2'' lift, with roller rockers more is better as long as you dont cut your guides too much,use bronze guides not cast iron.if you use your old cam gear think about advancing it a little when you press it on the new cam to get your power at lower rpm, strokers dont last long at 6500 where most hot cams are designed to operate best.
a 48 tooth sprocket should be about right, if you use a 51 low gear will be all tire smoke, you'll have to experiment with overall gearing after you get your motor broke in, 3.36 or 3.23works good for my 96'' with a mild cam & a 5 speed
an E carb would work best but you can use a G or a modified CV if thats what you've got. none of them are as good as the injection with a power commander on the twinkies.
you'll have to check for loose & broken bolts every week or so on your shovel, (black allen bolts hold up better) but do it late at night with the door shut so the guys with the twinkies wont know about it & always tell them your shovel is a stock 74 that needs a tune up.

Answer 2

Something I notice seems to be missing when people ask basically how fast a bike of a certain engine size would be is that they are ignoring the weight factor.
A bike with just a few less BHP COULD outrun a more powerful bike if it weighs quite a bit less.
Most of the Harley's I was looking at weigh in about the 650-750 lb range. Mine is 540 lbs. Everything else being equal, that alone would make mine quicker.

Answer 3

to a stock 96" without the stage one upgrade, your shovel will probably beat it. depending on how you ride it if you are into launching it out of the hole and racing it you should also consider a upgrade on your clutch. if your tech is reputable as you say he should know what to put into the bike to make it a daily driver but yet stomp on other bikes when needed. good luck

Answer 4

Yeah, I think it'll beat it - especially if it's in a light frame. And it'll do it with a lot of soul... A Crane ignition might be a good choice for that dual-plug setup. Crane Cams, valve springs and Barnett clutch disks and springs, and a Thunderheader might also be good choices if you can afford em...
Ride safe.

Answer 5

you will probably be able to stomp evo's, not so sure about trin cams, they are very quick winging engines for h-d's. shovels had a longer stroke and tend to wind up slower. on the top with the right gearing maybe. good luck, nothing sounds quite like a shovel with drag pipes, especially a big bore shovel.