Currently running a 1998 fxstc 80 incher with 10.5:1 comp, SE-57 cam, SE ported heads, Jims lifters, Crane roller rockers, Edelbrock dual carbs, Paul Yaffe by supertrapp 2 into 1 pipe. Due to a recent cylinder base gasket leak planning a massive overhaul and wanting to add a cube or to while I'm at it. Please critique the plan below.

Retain SE ported heads
Retain SE-57 cam
Retain Edelbrock dual carbs
Retain Jims lifters
Retain pipe
Axtell 3 13/16 bore iron cylinders with pistons
Jims 4 5/8 stroker wheels
Grand total of 106 ci
Daytona Twin Tec 1007 ign

Assuming the 98 cases manage to stay together, what do you think the numbers might be on this setup and or any weak links cam, head combo?

Thanks for replying to a post that implies you are a master at stroking

All replies greatly appreciated

 

I had a JIMS stroker kit in my original motor, giving me an 89 inch and looked into increasing the bore with Axtell cylinders. My motor was an earlier evo and I decided it would really need new crankcases. With labour costs and lots of new parts I decided it was better to buy a new motor! My S&S 107 does me fine. Bore and stroke are very different to what you have in mind but in touring trim I am getting over 100 HP and TQ. A more serious tune would give lots more.

 

Built a bunch of 106" Evo's, 108" Shovels. Set up correctly, they run VERY well.
What do the heads flow??
What compression??
Really should dump that carb set-up, if looking for good power, and consider an S&S G/Thunderjet, 45 Mikuni.
Will also add, that most anything with Paul Yaffe's name on it, is cosmetic, not power.
Scott

 

Never have done one with that big of a bore with thru studs on late stock cases. Have done ductile iron cylinders with base nuts and head bolts though. It ran for 5 years untill Curt bought it and ran the snot out of it. Now it has new cases, Ultimas.

 

To be honest I dont know what the heads flow, whatever mildly ported SE's will do. Like to stay at the 10.5:1 mark on compression. Unfortunately, somewhat of slave to looks as well as power, carbs and pipe. I know this setup is not the most optimal for power just wanting to make sure nothings going to really kill performance. This was my first engine build and got caught up in the wrong numbers as you may have guessed. I am thinking bumping the cubes to 106 should make these heads and cam a lot more productive. I just wanted to make sure they wouldnt end up choking a 106.

Thanks for the replies!

 

Probably would want to have a reputable shop flow test the heads to give you the best answer. My buddy Rich Coalson has a stunning running and looking 106" engine in his Heritage. He used STD cases, Hyperformance ductile iron cylinders and billet R&R round fin heads. Curt also has these heads on his.

 

The guy that will be boring the cases will be able to flow the heads, he actually flowed them after he ported them but it has been so long ago I cant remember the #'s. How much more port work is actually needed to accomodate the 106. I know 26 more cubes are going to breathe better, I guess I was under the impression that the thing to do these days was shrink the ports to boost velocity. What is the general rule of thumb regarding iron vs nik a sil cylinders for these builds? I get iron not expanding when hot to maintain accurate comp and valvetrain specs, but does it wear faster and what about heat dissipation?

Thanks for all the help

 

You'll get along with the cam/cubes, but ya' gatta' get rid of that carb set-up.
Have seen 20 hp loss on 113"'s with that vs. an S&S G/Thunderjetted.
Scott

 

got the same bore/stroke in my softail (streetbike),146 at the wheel,runs 10.9`s in the 1/4.great combo.have done many 3.812 bores with stock cases,no probs(its for sale!!)