Author Topic: Head work on stock motor  (Read 1908 times)

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Offline Helmwurst

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Head work on stock motor
« on: July 19, 2016, 07:27:30 PM »
Larry, have you had any customers request one of you head jobs on a stock 103 Rushmore motor? I was wondering if there would be any advantages in port and polish job on stock heads with the103 HO... Just got back from the tuner with a set of Rush head pipes 2-1-2, Kury muffs, and SE oval a/c and came out with 107 tq. Pretty good number I thought but got to thinking, what would happen if Larry worked his magic....????

Offline joe_lyons

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Re: Head work on stock motor
« Reply #1 on: July 20, 2016, 05:28:00 PM »
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Offline wfolarry

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Re: Head work on stock motor
« Reply #2 on: July 22, 2016, 02:53:12 PM »
107 tq is pretty damn good. The gains from porting come from a better valve job & cleaning up the ports for smoother air flow. On some heads a minimum amount of work can return maximum benefits. You'd be surprised how many stock heads I take apart where the valves have a poor seal. Run it for a season until everything stops moving then get some work done if you want & it'll last a long time. Might even gain a few ponies.  :wink:

Offline Mountainman streetbob

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Re: Head work on stock motor
« Reply #3 on: July 24, 2016, 12:52:46 PM »
Larry, I am still toying with almost the same idea as Helmwurst just taken 1 step further...

After seeing the dyno of what your 110 heads on rocktop's 117 did with the 2"?  rb racing lsr spyder (big hole I believe) I am positive you have found an excellent set up to work with my pipe.

I was wondering what you think of blueprinting the top end on my almost stock 2013 fltru which has a 1.75" Rb Racing PRO LSR Spyder exhaust. I am looking at this as an experiment to see how much we can get out of the factory pistons/cylinders and bottom end with the TB,Intake and exhaust I already have.....

I will Zero deck cylinders so the factory flattops are even.

Can you port/polish/flow/melt my factory 2013 heads to my TBW SE58mm manifold-throttle body and flow/melt the throttle body to the Boyeson x wing intake back plate and enlarge/blueprint the intake tract of the back plate for max flow...

The heads I believe should have the chamber volume at or near 79cc depending on the cam, modify the se58tb manifold and intake ports to fit each other now that that the ports are lower and closer together, replace valves and springs to handle  the lift and flow characteristics of the cam similar to the following: 

 (S&S 570/585/635), (TMan 590,625,660), (woods tw8, 9b, 400, 408), GMR600... Open to suggestions...

My top picks would be the Tman 660, S&S 635, GMR 600, Tman 590...

I am looking for BROAD power... 2250-6250, 2500-6500, :SM: :up:
100ft lbs before 2500, 125 hp @ 6250, A hp line that is still going up from 5250 to 6250 minimum and maybe even 6500 would be better :smiled:

On the left side I just need more than my 255 cam is currently doing with 100@2400 and 115 near 3200 to 4200....

The 570 is a neat cam but I would like a little less to the left and a little more hp and rpm to the right...
590 and 660 seem to both be wide/broad powerbands... :bike:

GMR 600 seems to be AWESOME :chop:

I love the torque rise and width of the powerband on 635 :baby:

625 is a left side cam USUALLY I love how quiet it is and when woth the right heads, exhaust, intake, compression it is a VERY STRONG, Quiet, NON PMS cam in my experience...

Thanks For any advice on this odd low buck build... :hug:

My highway cruise range is 3300rpm - 2800rpm , city cruise range 1900rpm-2600rpm and I believe the above cams are pretty good choices for that.

Brice H Dyal  The "Mountainmman"
US Army 89-01 35H/12B US Army AMC

Offline Helmwurst

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Re: Head work on stock motor
« Reply #4 on: July 25, 2016, 01:29:55 PM »
Thanks for the update Larry. I'll put that up on my grease board in the shop. :potstir: