Best Size BBF Stroker???

Just wondering what the experts feel is the best STOCK BLOCK BBF Stroker size? I have heard that the 4.300 stroke 514/521 combos are probably the best, just curious to see what others think  

Personally if I were buying a stroker my money goes into a 4.500 arm. Just my 2 cents.

Depends on the top end and the application IMO

Yep, application and which cyl. heads would matter.

Can more stroke hurt

I wouldn't use the word 'hurt' but, I can think of a few applications where I'd rather have a 533" [4.440" x 4.300"] than a 545" [4.390" x 4.500"]. It'd depend on the cyl. head/valve size and rpm range needed.

dfree383 wrote: Depends on the top end and the application IMO

YEP ... the top end will determine the best bottom end for the application.

4.68 bore but pump gas and "street friendly" cam for drag week style build????

In a 2 bolt block i'd stay 4.3.IMO.....for sure if its a race motor.

what would be considered the best size for the P51 heads as out of the box?

Larry Williams wrote:what would be considered the best size for the P51 heads  as out of the box?

I'd say something like a 533 / 545 CID for out of the box. But why? Why not just go ahead and do some porting and flow testing work, and then they can be used on anything up into the 557 / 572 CID range.

For example Bobby Shrewsberry's 557 made 942 Hp and he won the Ford Bash that year in his dragster. Randy Moore's 562 made 951 Hp and won a lot of races. Blake da Snake's 588 makes 1003 Hp and runs dang good.

Hope this helps,
Charlie

c.evans wrote:

Larry Williams wrote:what would be considered the best size for the P51 heads  as out of the box?

I'd say something like a 533 / 545 CID for out of the box.  But why?  Why not just go ahead and do some porting and flow testing work, and then they can be used on anything up into the 557 / 572 CID range.

For example Bobby Shrewsberry's 557 made 942 Hp and he won the Ford Bash that year in his dragster.  Randy Moore's 562 made 951 Hp and won a lot of races.  Blake da Snake's 588 makes 1003 Hp and runs dang good.

Hope this helps,
Charlie

i have them sitting on a 545 in the garage now. I should have taken them with me 2 years ago for you. now its a spare motor till I get to Ky with my bigger motor for repairs.

thanks for the input Charlie

A question if I may? Using factory blocks, will the longer stroke (4.5") interfere with longer cylinder barrels and with the longer stroke (4.5") is there enough cylinder (shorter cylinder barrels) to stabilize the piston at BDC?

Dave.

LivermoreDave wrote:A question if I may? Using factory blocks, will the longer stroke (4.5") interfere with longer cylinder barrels and with the longer stroke (4.5") is there enough cylinder (shorter cylinder barrels) to stabilize the piston at BDC?

Dave.

There are no interference problems with any factory blocks with a 4.5" stroke using a rod having a capscrew type bolt..
With a rod having a through bolt, the bolt head will slightly interfere with a later longer cylinder bore block.

c.evans wrote:

Larry Williams wrote:what would be considered the best size for the P51 heads  as out of the box?

I'd say something like a 533 / 545 CID for out of the box.  But why?  Why not just go ahead and do some porting and flow testing work, and then they can be used on anything up into the 557 / 572 CID range.

For example Bobby Shrewsberry's 557 made 942 Hp and he won the Ford Bash that year in his dragster.  Randy Moore's 562 made 951 Hp and won a lot of races.  Blake da Snake's 588 makes 1003 Hp and runs dang good.

Hope this helps,
Charlie

Charlie? What heads were on these 3 motors you speak of?

Ace

Did 870hp on this years 572 EMC engine with P-51s. Hot street setup with a hydraulic roller 11.4:1 and a 4150 carb

powerstrokeace wrote:

c.evans wrote:

Larry Williams wrote:what would be considered the best size for the P51 heads  as out of the box?

I'd say something like a 533 / 545 CID for out of the box.  But why?  Why not just go ahead and do some porting and flow testing work, and then they can be used on anything up into the 557 / 572 CID range.

For example Bobby Shrewsberry's 557 made 942 Hp and he won the Ford Bash that year in his dragster.  Randy Moore's 562 made 951 Hp and won a lot of races.  Blake da Snake's 588 makes 1003 Hp and runs dang good.

Hope this helps,
Charlie

Charlie? What heads were on these 3 motors you speak of?

Ace

Fully ported and flowed P-51 heads on those three engines. It was in response to Larry's question.

Then Dave mentioned that his P-51 headed 2012 EMC contest engine was 572 CID and made 870 Hp. Again those were fully ported and flowed P-51 heads. I put the bigger 2.300" intake valve in them.

Charlie

Thanks Charlie. I just did a 557 a460 head deal. Waiting on a cam right now



Ace

From what motors I built you can not go wrong with a 4.500" stroke with a 6.800 rod even in a short wall Dive block, 4.390 bore even with ported D3 heads are torque monsters ,ie 450- 500 ft/tq @ 2200 rpm or less
Frank

combos i found work best were 4.44 bore 4.150 stroke, (514) 4.390 with a 4.500 stroke (545 or the 4.44 bore with 4.500 stroke (557) and a 4.42 with 4.500 (552). we've used all these combos and work great.

cool40 wrote:In a 2 bolt block i'd stay 4.3.IMO.....for sure if its a race motor.

why say that? its not a bowtie dont need the 4 bolts to make the power lol  

Rickyt630x wrote:

cool40 wrote:In a 2 bolt block i'd stay 4.3.IMO.....for sure if its a race motor.

why say that? its not a bowtie dont need the 4 bolts to make the power lol  

for a race motor 4 bolts are better than 2. my 2 bolt d0ve block had a little cap walk but held up fine. i guess i should have said UNDER 7000 RPM.   

Even good stock block should be 4.5". Are you going to cam it enough to turn it high enough to matter? DW deal spends 99% of the time at idle to light load cruise. The length of the arm doesn't matter for that. Other than a high rpm deal the side load concerns are not a huge deal. Trying to spin it brings a bunch of concerns with valve train parts.

cool40 wrote:

Rickyt630x wrote:

cool40 wrote:In a 2 bolt block i'd stay 4.3.IMO.....for sure if its a race motor.

why say that? its not a bowtie dont need the 4 bolts to make the power lol  

for a race motor 4 bolts are better than 2. my 2 bolt d0ve block had a little cap walk but held up fine. i guess i should have said UNDER 7000 RPM.   

                                                                                                                           I have a Question, Cool40 has a good point. I have not seen cranksfaft balance mentioned yet. If an engine was to operate at 5-8500RPM, would it need to be balanced in this range, and not at a lower RPM level range?

http://www.circletrack.com/enginetech/ctrp_0504_engine_balancing_tech_terminology/ Interesting article, especially the 427 Ford coments.