[Jreif80]

hey guys i did some searching here and couldn't find anything how would a big bore say at least 4.44 429 act or even a destroked 429 say maybe if it's possible to destroke it to a 3.5 stroke with a 4.44 or maybe even a 4.5 inch bore would that just be too small of a stroke and not have great cylinder fill? just curious i'm not building an engine now but i love gaining knowledge and hearing about your experiences. i was thinking hey what is the biggest engine with the shortest stroke availible, i would think a 444 ci motor built to spin could be interesting

 

[dfree383]

IMO it would be a waste of time, costs the same to go big and it will make alot more power.

 

[Outlaw5.0]

hey guys i did some searching here and couldn't find anything how would a big bore say at least 4.44 429 act or even a bestroked 429 say maybe if it's possible to destroke it to a 3.5 stroke with a 4.44 or maybe even a 4.5 inch bore would that just be too small of a stroke and not have great cylinder fill? just curious i'm not building an engine now but i love gaining knowledge and hearing about your experiences. i was thinking hey what the biggest engine with the shortest stroke availible like around a 444 ci motor built to spin could be interesting

Man that would be very interesting considering the 10.300 deck height. Even the 3.850 stroke of the 460 is capable of high rpm, its really still a small block stroke. Unless your race a specific class or need to give up lowend torque, there is no reason to use less then a 4.250 stroke with the 10.300 deck.

I went with a "custom" 9.400 short deck block engine with a 3.750 stroke, but it will also see over 9000 rpms in a drag radial car.

 

[Jreif80]

I see

what you guys are saying i have just had that on my mind the last couple days so i was wondering about that also why do people destroke engines? is it mainly due to a specific class or rules they race in or are there actual performance reasons why once in a while a guy will destroke an engine?

 

[dfree383]

Not many builds I've seen are wanting to destroke something, unless its a weird class like Comp Eliminator or something like that.

 

[rmcomprandy]

A lot of engines aren't nearly as "oversquare" as the Ford big block is already.

oversquare = bore/stroke when the bore is bigger
undersquare = stroke/bore when the stroke is bigger

 

[Lem Evans]

De-stroke = class rules or bad meds .

 

[4speed390]

there are reasons to destroke a motor and use a bigger bore, however none of them may apply to your application. To start achieving higher rpms with more durability and less harmonics, also to allow for more power with the sacrifice of torque in certain rpm ranges. Pro stock does this on all competitive engines today. Typically a bore size is 4.725 or so with a stroke to make 500 ci, i forget at the moment its 11:30 my apologies. They are able to utilize the huge amouts of air they take in and use the ports and the cams to their fullest potentials in the upper rpms. Typically they will see over 10,000 rpms, usually more. The bigger the bore the more air that will be taken in, so you can use bigger valves and heads, but as I said it will sacrifice torque in the lower part and make the motor very unstreetable, should you decide to drive it.

 

[Outlaw5.0]

there are reasons to destroke a motor and use a bigger bore, however none of them may apply to your application. To start achieving higher rpms with more durability and less harmonics, also to allow for more power with the sacrifice of torque in certain rpm ranges. Pro stock does this on all competitive engines today. Typically a bore size is 4.725 or so with a stroke to make 500 ci, i forget at the moment its 11:30 my apologies. They are able to utilize the huge amouts of air they take in and use the ports and the cams to their fullest potentials in the upper rpms. Typically they will see over 10,000 rpms, usually more. The bigger the bore the more air that will be taken in, so you can use bigger valves and heads, but as I said it will sacrifice torque in the lower part and make the motor very unstreetable, should you decide to drive it.

And the NHRA 500 c.i.d prostocks use a 9.00 deck height vs the 10.300 of the stock bigblock, its really just a 4.900 bore space smallblock.

 

[DaveMcLain]

I would say that given the tall deck height of the big Ford having a stroke much shorter than 3.85 is less than ideal. Either the piston ends up being tall and heavy or the rod ends up being too long.

By the way there is NO torque advantage to a longer stroke smaller bore engine, that is a fallacy.

 

[Jreif80]

thanks

hey thanks guys i really appreciate all the responsses like i said i am not looking to build a destroked motor just been wondering about them and why people do them what i want to build when funds are availible is a decent reliable 429 that i could once in a blue moon take it to about 6200 rpm you know solid cam iron heads so i am thinking of having my buddy give me his complete c9 block c8 headed thunderjet he has laying around from what you guys have been saying it seems to be a decent foundation now as far as heads go i like factory iron heads when they are appropriate would the c8-d0ve heads like just switiching to 2.19 intake and 1.73 exaust and smoothing the transitions after cutting for bigger valves? not looking for an insane motor just something reliable and rip snorting for mild iron headed solid cam 429

 

[CBSuperduty]

Not sure on specs but Bret Powell runs a fairly short stroke/bigger bore combo in his 4x4 pulling truck. I think that it is in the 480CID neighborhood and has iron CJ heads. Check out the videos below. He likes to wind it up into the higher R's.

http://www.youtube.com/user/BretPowell

 

[dfree383]

6200 isn't a big deal with a 3.85. 460 crank or a stroker, if you buying part build it bug it will make more power for the same $$$

 

[lghting94]

I actually ran a combo very close to what you are talking about 3.5 stroke (destroked 429 crank) 6.800 aluminum rods and .030 over 460 pistons comes up to 424 cid. Never dyno'd the motor but it was the fastest reving v-8 engine i have ever seen and it did like to go upstairs(went 10500 one night by accident). I used pi heads on it with a victor dominator intake. I still have all the parts(except pistons) to put it back together just not the time or money. I had problems finding a piston with enough dome to make good compression with pi heads.

 

[waterslinger]

I ran a 4.600 bore and 3.300 stroke deal for a bit it was a RPM lover. It was from Tim Lynch and Steve Petty when the were running a cube to weight deal.

Still have 10 pistons (8 with 15ish runs and 4 new) and the 6.860 BME rods. Trade or sell cheap!

 

[Dennis Griffin]

was wondering what the rod journal size is.

 

[BOSS 429]

have done some 3720s to 5.000 stuff, and a 3520 arm.

all but the 5.000 we have spun to 9500 and then a little

pro stock uses short, or destroked stuff because of rules, that way they can stay under 500ci using a big bore 4700ish

 

[BOSS 429]

was wondering what the rod journal size is.

1.900 on a few

 

[BOSS 429]

6200 isn't a big deal with a 3.85. 460 crank or a stroker, if you buying part build it bug it will make more power for the same $$$

lot easier to build it big as said