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Shovelhead bigbore/stroker owners!

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Old 03-27-2010, 05:53 PM
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Default Shovelhead bigbore/stroker owners!

Hey guys..looking to compare notes with fellow shovelhead bigbore stroker owners..(or whoever has built them)

anyway, what I`m hoping to hear about, is info, thoughts, opinnions from guys who have ran, or runs shovelheads, with 4 1/2in stroke cranks, and .200 over lengh cylinders...

the 93in S&S sidewinder kit for late model shovelheads, uses 3 5/8 bore cylinders that are only .075in over in lengh, & 4 1/2in stroke flywheels..
I`m very familiar with that setup, as i have one..

but what I`m wanting to hear about, is guys who are running 4 1/2in stroke flywheels, with 3 5/8 bore, .200 over lengh cylinders.
I believe compression ratio would only be around 7.5:1...depending on piston?.(unless there are any other options with this combo??)

anyway, does anyone out there run this setup? if so, can you post your thoughts and opinnions on it?

it`s a long story, but in short, lets say I have a shovelhead motor, with 4 1/2in stroke flywheels, and .200 over cylinders...

what would be your opinnion on pistons, and ratio`s?

thanks in advance for any and all thought & opinnions!!


Last edited by FXRSBIGBORE; 03-27-2010 at 05:55 PM.
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Old 03-27-2010, 06:17 PM
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I am running the S&S Big Bore with a Andrews C grind cam,Solids,Super E carb,Dual Plugged,Crane Fireball Ignition and lower Compresion pistons in a 1981 FLTC.
The only way to describe it comparing it to a stock 1340 Shovel in the same frame is
night and day!Most of the stock shovels of that vintage are dogs being left in the dust by the old 74 inchers and with my modifications I now have come up with a Great Perfoming set-up for the weight and the fuel that is available.
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Old 03-27-2010, 06:47 PM
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Thanks for the reply flying..

See what going on is..i basicaly destroyed my rear cylinder, which was an S&S 3 5/8 bigbore stroker, S&S only sells their cylinders in sets of two, for well over $600..
and, for my kit, ONLY S&S makes pistons that will fit (needless to say, the S&S pistons are VERY expensive also), anyway although i have a 4 1/2in stroke crank (which obviously means my pistons come up .125in higher) cylinders are an unusuall .075in over length..they acomplished this, but producing pistons, that were not only short skirt to clear the crank, but their actually shorter from the wrist pin to the dome (.050in shorter), so it all worked out..

anyway, .200 over cylinders are MUCH less expensive, as are the pistons for them...
but where my confusion comes in, is i`ve seen .200 over length 3 5/8 bore cylinders advertised, for shovelheads with a 4 1/2, 4 5/8, or 4 3/4in stroker cranks..but i can`t find any info on which pistons to run, for which stroke?
so i can only asume, they se the same piston, and what happens is the ratio varies depending on what stroke your working with?
which may seam rediculess...but I`ve spent quite a bit of time trying to figure this all out, and from what i`ve seen advertised in the book at my local parts dealer, is that it list the same piston numbers for the .200 over cylinders, then list all three strokes also?

so anyway, that`s why i`m trying to find someone, who might be running a shovelhead with a 4 1/2in stroker crank, and .200 over length big bore cylinders...

I guess i should add..that a friend of mine came into a BRAND NEW set of .200 over length big bore cylinders, so if i can confirm that this combo can be done, has been done, and hopefully runs good..I`ll be on the road soon...(my shovelhead has been down for a few years..really wanting to get er back on the road..)

Thanks again for the reply..

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Old 03-28-2010, 02:50 PM
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I run a 4 3/4 stroker with .200 longer cyls..I scored the cyls real cheap bout 6 yrs ago..I phoned S&S told them I have .200 longer cyls, with 4 3/4 flywheels and said I wanted 10.5-1 forged pistons for them..So they sent me a set..They were bout $275.00 a set..
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Old 04-04-2010, 06:23 PM
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Default cylinders

If memory serves(fails) me, my current setup that was re-done due to a valve spring failure... OUCH!5-6 yrs ago is s&s 9.5 pistons,then my local dr. evil shortend the cylinders approx. .025-.030 to get piston (quench)up flush,resulting in approx. 10.2:1. Iam guessing i started out with the shorter cylinders.Iam very happy with this set-up.
96hp/98 tq

1980 FXEF
93" 10.2:1,96hp/98tq
baker 6in4-11.98-114mph
4-2-10 My new windshield(thanks Hapbob)
08'S/G slow-bone stock.Then again,maybe not
S&S 106,TTS,Woods 7H,10.6:1,104/112...for now
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Old 04-06-2010, 09:45 AM
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Thanks for the reply`s everyone...I`ve ran across one too many problems/issues with going from my .087in over cylinders to the .200in over lengh cylinders..

by the time all was said and done..
I`d be looking at a new wider intake, longer push rods, longer oil line from case`s to rear head, and most importantly, a non matcjhing cam, due to the fact that I would have been running about a 7.5:1 compression, vs 8.5:1 that I would normaly have with the right hieght cylinders & pistons..i could have corrected this some by decking the cylinders stc...
but it just got to the point, to where I really would`nt have saved much, if any money..and I would have running some no name brand cylinders & pistons..
screw it..
I went down to my local shop and ordered the correct matching cylinders & pistons last week..cost an absolute fortune..but atleast i know everything will be correct..

thanks again for all the reply`s..
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Old 09-12-2011, 09:42 PM
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I have a 98" shov with the .200 taller barrels..convert to external oil lines myself..S&S kit included barrels and 92-1800 series forged pistons,4 3/4 flywheels,adjustable pushrods and longer tube retainers,matched intake for taller barrels....bought S&S dual plug heads and sent them straight to flow bench(their stock castings are just plain ugly inside,need cleaning up) with a Andrews C grind..runs like a raped ape..motor was cc'd at 9.4-1 comp...if you dont clean up the head you will come out with max 9.5-1....kinda wondering how stroker93 got his 10.5-1 pistons when I've been calling every manufacturer there is for the same and am told they have to be custom made..minimum quantity of 4 for $700+
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