4.3 Stroke Discussion

It seems(and I could be wrong) that when discussing BBF stroker combinations that the 4.15, and 4.50 stroke combinations seem to be far more popular than the 4.3 stroke combinations. Is there a particular reason for this other than RPM, and pure cubic inch. I admit I have very limited exposure to 4.3 stroke combinations and that this is purely driven by my curiousity. I would think they would be more popular than they are ( maybe they are more popular than I am giving them credit) and in theory I would think they would rev faster than a 4.5 stroke motor, and have the potential to make more torque than a 4.15 stroke. Given the limits of a stock valve layout head that may not do well at supporting 545+ I would think it would be a nice compromise. I am also not a big fan of having a larger stroke than bore( which could also be in my head). As stated earlier I started this topic for discussion and to satisfy my curiosity no more no less. So feel free to call me a retard.

4.3 works for for me............

To me it seems lately (past year or 2) the 4.3 seems been the choice more often than the 4.15 stroke. The 4.15 seemed more popular 5 years ago than it is now. IMHO.

richter69 wrote:4.3 works for for me............

Yeah, but your SSSSSSSuper SSSSSSSpecial...

Diggindeeper wrote:To me it seems lately (past year or 2) the 4.3 seems been the choice more often than the 4.15 stroke. The 4.15 seemed more popular 5 years ago than it is now. IMHO.

To me it seems like EVERYONE seems to be running a 4.5 stroke. We have a 4.15 stroke deal up here on thhe sauce thats a revvin mofo. I dont personally know more than a couple guys runnin a 4.3.

Ky has a 4.3 deal too, so does Bruno. I know mine and Ky's will twist on up there...........

Am I right in assuming the 4.3 would typically rev faster than a 4.5?(I dont mean a 600+ inch moster though).

richter69 wrote:Ky has a 4.3 deal too, so does Bruno. I know mine and Ky's will twist on up there...........

For some reason I always thought Bruno's and KY's were 4.5 deals. It would probably help to read more.

I think they are all the same bore also, 4.56


I think its a deal where most go for the 4.5 as most everything is the same price wise. I was originally gonna use a 4.3 crank I got a good deal on (cast), and already bought pistons etc, I went with a A460 block, no longer wanted to use a cast crank, went forged but already had the pistons etc. I could have used a 6.7 rod and went 4.5..........but some older wiser fella talked me out of it...........

4.25 now but 4.5 next.

Barney wrote:

Diggindeeper wrote:To me it seems lately (past year or 2) the 4.3 seems been the choice more often than the 4.15 stroke. The 4.15 seemed more popular 5 years ago than it is now. IMHO.

To me it seems like EVERYONE seems to be running a 4.5 stroke. We have a 4.15 stroke deal up here on thhe sauce thats a revvin mofo. I dont personally know more than a couple guys runnin a 4.3.

I was more so just comparing the 4.15-4.3 thing.
I agree the 4.5 deal is popular.
People are just size queens.

will the 4.6, and 4.75 start becoming the next fad????

it's the BIG factor for most folks.the more cid for the same money.

Diggindeeper wrote:

Barney wrote:

Diggindeeper wrote:To me it seems lately (past year or 2) the 4.3 seems been the choice more often than the 4.15 stroke. The 4.15 seemed more popular 5 years ago than it is now. IMHO.

To me it seems like EVERYONE seems to be running a 4.5 stroke. We have a 4.15 stroke deal up here on thhe sauce thats a revvin mofo. I dont personally know more than a couple guys runnin a 4.3.

I was more so just comparing the 4.15-4.3 thing.
I agree the 4.5 deal is popular.
People are just size queens.

will the 4.6, and 4.75 start becoming the next fad????

no,unless procomp sells them.lol

cool40 wrote:no,unless procomp sells them.lol

OH SNAP!

I actually like the 4.15, but its good to know theres no black sheep factor to the 4.3.

In most cases, the torque is what will make an engine rev faster. Over square bore stroke combos will work just fine too. The shorter stroke seems to be a little easier on the pistons from what I have gathered. I've seen the iron CJ's on engines as big as 665ci and perform just fine. Do what you feel will do what you want. No matter what you chose it will make a pile of power.

I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

'65 T-BOLT wrote:I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

Never thought stroke had anything to do with how fast an engine revved...................

IDT-572 wrote:

'65 T-BOLT wrote:I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

Never thought stroke had anything to do with how fast an engine revved...................

Im sure it don't Blake! but my stock stroke 460 will not rev as quick as the 521

IDT-572 wrote:

'65 T-BOLT wrote:I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

Never thought stroke had anything to do with how fast an engine revved...................

As in how the engine accelerates or what maximum RPM is attainable...?

rmcomprandy wrote:

IDT-572 wrote:

'65 T-BOLT wrote:I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

Never thought stroke had anything to do with how fast an engine revved...................

As in how the engine accelerates or what maximum RPM is attainable...?

I was speaking as in how the engine accelerates, but apparently stroke never factors into that.

I have a 4.300 in my A460 motor, Revs fine......

cool40 wrote:it's the BIG factor for most folks.the more cid for the same money.

That's the deal.......more cubes for the same $. If there are no c.i.d. rules people tend to buy the longer strokes.

IDT-572 wrote:

'65 T-BOLT wrote:I have the FMS 4.3 cast crank, revs as quick as my 427 windsor!

Never thought stroke had anything to do with how fast an engine revved...................

OF COURSE STROKE matters, and even more with a head like cj/scj ,then add a small bore to the mix.


mainly the weight of the big crank, this has been check on dynos with timmers, for the same reason prostock engines have very small cranks,and clutches

I have a 4,300 makes 840 ,but its done by about 6800 we have ran it with all kinds of diff intakes,carbs,etc all the way to 8200.port plates,different headers etc.from 27 deg of timing to 45 total

its just done

another great test is that it was in a pull truck for 3 years, now its going in a drag car,and we will test it some more