555ci bore vs stroke

Hi all, I am looking at starting a new engine combo for my 34 strip car. Just wondering what your suggestions are on bore and stroke combos for a 555Ci BBC. I was going to run a 4.560" bore and a 4.250" stroke. Would I be better off running more stroke and less bore? This car will purely be for the 1/4 mile. I will be running a solid roller with approx. 268 @ .050". Comp will be around the 13:1 mark. I will be running a glide with a converter at around the 5000rpm mark.
Also, I have a pair of Pro Topline cast iron heads, I think they're 360cc and flow up around the 400cfm mark. Should I use these or should I buy a good set of alloys?
Thanks in advance.

Any specific reason you desire to run 555cid? And why the nasty converter? I am not ridiculing but want to help, it's nice to know where and why you have these numbers planned out. I like 4.500 bore with 4.325 stroke and keep the converter down to 4000. I have built this combo for the strip a few times and the combo is very compatible to every car they've been in. I do like the alloy head idea also. Is the 34 going to only see the strip? No street driving?

the 4.560 bore with the 4.250 is a Srp piston on the shelf ...good way to go yes .the stall is hi? how much CFM are you going to run with this ?the heads are fine if they will flow 400 cfm . a 4.600 bore work good to like 565 have built some and the 555 and 582 4.600 with a 4.375 a lite car how much lift and lsa ?? the @.050 could be bigger

As it will only be hitting the strip I was going to go the bigger converter. But keeping in mind, i will dyno the combo first and see exactly where the torque is, then select converter.

a very lite car will need more stall did a 28 ford with a548 14.8 cr with a 1150 cfm used a 4500 stall in it for the street

Haven't selected camshaft as yet. Induction will either be a 1050 dominator on a victor or dart manifold or I also have a victor ram with a enderle bug catcher on it. I'd rather run the later. Any camshaft opinions?

there is a luntati 50237 284/292 782/712 or isky 396770 770/770 284/284 lc108 there is many but something round here? for a hi winder you may want the 4/7 swap i will look in to my grinds and see. i have used one cam in the past that did work good if i can find the numbers you could use the profiler or the super victor .i have a howards cam that is new 4/7 swap 710/714@050 270/278 if you want to try a smaller cam it will be on ebay this week end

Do you know how much cfm the enderle hat flows? the throttle plates are 4.125 each.
Should I use the pro topline heads for now. Once I get my flow bench I will flow them and see exactly how good they are. I'd rathjer run a slightly smaller intake runner. What do you think?

well you will need a 400 cfm port you can get BMF heads that flow that at 750 lift with 330 cc port runners or the darts 355 heads your heads will work. i do not know how good they your heads will flow? i know the 861 chevy were 375 cc or so and could flow around 400 maybe more at 800 lift no do not know how much your hat will flow ? if you have a flow bench flow it ?

What are BFM heads?

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Originally Posted by 555rod

What are BFM heads?

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sorry. BMF heads. it late just punch that in that should get you to there web page

www.bmfracing.com

Checked them out, the BMF 330cc's don't look to bad. Have you had much success with them?

i have a set of the 330 that i am not using that i pick up .i have customers that have there heads . i would use them if i was going to build a engine for someone at this point in time

what condition are they in?

Building new stroke and bore combinations is a very specific science that that determine reliability and the personality of the engines performance. Many of the desktop engine dynos will alert you of potential problems with the pure mathmatics of a combination but they will not alert you of the mechanical problems you may run into.
The mathmatics side of bore & stroke combos are issues like improper rod to crank depature angles or thrust ratios that just will not live very long. These ratios modify the side load - dwell - and thrust angle while defining the HP / torque curves. The mechanical problems like a piston skirt hitting the camshaft or rod cap clearance to pan rail is only available in much more expensive software. This is still much cheaper than ordering custom parts to find they simply do not fit in the case with the clearances needed not to mention if they should work together in this combination or not.
Stay with packages or shelf stocked combinations so you know if the block can be messaged enough to keep you out of the water passages and if small enough base circle cams are even available. Let somebody (like the aftermarket manufacturers) with tons of dyno time and money complete the R & D to prove the benifits of a bunch of parts bolted together or if they will all bolt together.
I have a 540 inch Shafiroff comp elim. engine just sitting in the shop waiting for me to build something to put it in I will probably never get too. I had her in a 2200 pound Cobra but just got tired of having to trailer to all the car shows. I could not carry enough fuel to get there much less get home on the 17 gallon cell capacity I have. It is 12.4 C/R so needs 110 octane min. to run on gas. Alky cut my usable milage in half so a trailer queen. These guys own the market for turn-key combiations or rotating assemblies IMHO but are always trying new things in the dyno room but it is hard to beat the tried and true numbers now being delivered.

i have had 548/572 that see 7500+ all the time. the rod to cam is not a big deal less you run alum rods with steel rods you can run up to 4.750 with std base cam. but every thing needs to be check this is done all the time the 4.250 crank with a 6.375 rod i have built over 20+ of them from 486-565 they all work just fine the desk top will not tell you were or how much you need to cut out in the block alot of the time with the right rods there is a small bit of work the bmf heads i have beryllium seats and are cut for T@D or jesel not the sportman crap