8.7 deck sbf, Whats the biggest stroke possible?
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8.7 deck sbf, Whats the biggest stroke possible?
Just wondering how much stroke is the maximum possible in a 8.7 deck sbf. ? 3.850 with 5.625 rods and 1.15 compression height?
Whats been done? I cant find much of anything on the net. Cheers, Steve
Whats been done? I cant find much of anything on the net. Cheers, Steve
Your limits are:
a) pan width by starter
b) how bulky the big end of the rod is (pin diameter, capscrew vs. through bolt)
c) length of the bore (having the bottom of the wristpin drop much below the bore gets you into reliability problems)
d) how much room you have to grind for rod clearance before you hit water
I can tell you a 3.6" stroke in a 289 block is at the practical limit, but I have no idea how your 8.7" block compares to a stock Ford block.
a) pan width by starter
b) how bulky the big end of the rod is (pin diameter, capscrew vs. through bolt)
c) length of the bore (having the bottom of the wristpin drop much below the bore gets you into reliability problems)
d) how much room you have to grind for rod clearance before you hit water
I can tell you a 3.6" stroke in a 289 block is at the practical limit, but I have no idea how your 8.7" block compares to a stock Ford block.
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
panic wrote:Not aware of a 8.7" deck, more information?
X 2
WTF block are you using??
No stock block has a 8.7 deck height
Is it an aftermarket block such as Dart or World products or a off shore block???
Real Race Cars Don't Have Doors
Re: 8.7 deck sbf, Whats the biggest stroke possible?
Dart make them.panic wrote:Not aware of a 8.7" deck, more information?
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
SBF , will just reference 302 and 351 factory here for ease,, but these 2 blocks have the same pan rail widths, the same cam/crank c/line distance, now on the 351 block a 4.25" stroke fits with realistically very little trouble, a 4" stroke literally falls in there.
On the 302 block the bottom of the bores come a little closer to the crank centerline so counterweight and rod clearance here will be an issue.
So with your 8.7" block (i have not personally seen one) a 3.85" stroke may well be doable but realistically i would be going a little shorter in stroke and using the 8.7 deck bore length as a strength advantage for better piston support at BDC and just build to to rpm a little higher to regain any HP you may have lost by dropping stroke down from 3.85".
On the 302 block the bottom of the bores come a little closer to the crank centerline so counterweight and rod clearance here will be an issue.
So with your 8.7" block (i have not personally seen one) a 3.85" stroke may well be doable but realistically i would be going a little shorter in stroke and using the 8.7 deck bore length as a strength advantage for better piston support at BDC and just build to to rpm a little higher to regain any HP you may have lost by dropping stroke down from 3.85".
Craig.
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
Yeah, Dart, and SVO make a 8.7 deck block. Have seen a few diffent strokes that might work, 3.625 / 3.750 / 3.850 / 3.900 better RS ratio with 3.625 and 3.750, so maybe your right, spin it hard, though I was planning to do that anyway.
Re: 8.7 deck sbf, Whats the biggest stroke possible?
We have used a 3.6 stroke in an 8.2 deck before. Honda Manley rod 1.88 . minimal grinding. A 3.75 stroke in an 8.7 has been done also. Again. A honda rod with an 8.16 pin. It amazes me that a few" well known " engine builders haven't heard of an 8.7 deck sbf. A lot of good Ford comp elim. Engines are based off this block. Best manifold runner alignment for sure.
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
WOW over 5 years ago so what did you come with for a max stroke and did you actually build this engine.
Re: 8.7 deck sbf, Whats the biggest stroke possible?
8.7" is generally used as an alternative to the 8.2" for building 363-385 engines and maintaining a decent rod length.
Guys wanting max cubes will go with a 9.5" deck.
Guys wanting max cubes will go with a 9.5" deck.
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
Didn’t even «Ford Racing» dept. offer an 8.7 back in the day?
8.2-8.7-9.2-9.5
8.2-8.7-9.2-9.5
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Re: 8.7 deck sbf, Whats the biggest stroke possible?
YES, a bare block ... Intake manifolds, too.Caprimaniac wrote: ↑Thu Feb 02, 2023 11:38 am Didn’t even «Ford Racing» dept. offer an 8.7 back in the day?
8.2-8.7-9.2-9.5
For some reason, they didn't catch-on very well.
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