If i was to stroke a motor what would be the ramifications of it.
Would it mean that the engine will not rev as hard and reduce bottom end power but gain in top end?
Also if my car had no gears what would be better a huge stroke with a small bore or a small stroke with a large bore?

An increase in stroke is usually responsible for an increase in torque, all other things being equal.
Your maximum rpm level is dependant on a great many things, of whick stroke length is but one. There are engines out there with strokes of more than 4" [100mm] that are pushed to 9,000 rpm & the big Hemi Chryslers are sometimes [very] briefly overwound to about 10,000 rpm. [don't stand alongside]
How long a stroke do you plan to run, & how high to you want your engine to rev?

No gears? The longer the stroke, the more chance you have of geting it off the line.

to increese the stroke would loose you some revs but would give you better low end power (tourqe)
a longer stroke would be better for no gears
i think

dodge man said it betterer

Its for a compact speedcar so they have no gears or clutch. hence a rolling start.
I have been told that you can get a different crank, rods, pistons for an A12 and stroke it to around 1350cc and make some serious power. Also fitting a shaved/ fully ported A14/A15 head to it.
Is this true or is it a load of crap?

Cheers

hmmm, sounds to me that you are building a litresprint engine..

go for a short stroke / big bore combo, this will give better top end power which is want you are better with in this type of racing.

As far as I have investigated, there are more advantages with the short stroke option than there are with the long stroke option, that said there are still secrets in this game and I'm not the one to let them all out.

So MLS is that why you run a A12 for the smaller stroke with huge bore? or have you done something outragious that you dont want to share??

It's possible to use the A14 crank of 77mm stroke in the A12 block, replacing the 70mm stroke of the original crank, & if bored from 73mm out to 77mm you would end up with 1434cc. All using stock Datsun /Nissan parts, although the A14 crank will need some minor work in a lathe.

When the stroke is increased to 77mm in the shorter A12 block, the rod angle becomes greater, throwing increased side loads on the pistons, & this may defeat the advantages you seek in a high reving engine. I am building such an engine for street duty & it should serve well, ... but for race duty, ... it's your call.

Another option is to simply push the A12 bore out to 77mm using second oversize A14 pistons & the same A12a rods that would be used in the stroked engine. This will give you about 1304cc

So could you use an A15 block and de-stroke it. by using an A12 crank/ rods and reducing the height of the block?

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