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Old 09-29-2010, 09:10 PM
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Cubic inch formula for a 400 sbc

what would a 400ci based motor turn out to be with a 3.85 stroke and a .030 over bore for a total of 4.155 cylinder bore,an answer or formula would be greatfull.Thank you
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Old 09-29-2010, 09:19 PM
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Quick cubic inch calc for V8 engines : Bore x Bore x stroke x 6.2832 = cubic inches.

In your case it comes out to 417.62 inches.

Formula for any engine is: Bore x bore x stroke x .7854 x # of cylinders = cubic inches.

You can find a ton of online calculators at www.wallaceracing.com , on the Automotive Calculators page
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Old 09-30-2010, 11:21 AM
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CI Formula

Thanks again Eric My mechanic had a client of his abandon a fully forged motor that I just described for you to help me figure out what ci it is. it has a 2 bolt studded bootom end, with a scat forged crank ,scat procomp i beam rods with the 7/16 cap screws speed pro power forged floater pistons,L2489F 30 over flat tops with 2, 4cc valve releifs and an extra 1 cc cut into the eye lid for more clearance,the block alone has $1,700.00 in machine work done to it parts aside,I can pick up the whole assembled balanced package for $2,ooo,what do you think,I'm thinking go for it,could you give me your 2 cents worth please .Thank You.
PS WOULD I NEED A SMALL BASE CIRCLE CAM REGARDLESS OF WHAT i GO WITH ,i WAS THINKING OF THE COMP 12-678-4 WITH THE SPRINGS YOU RECOMMENDED FROM COMPETITION PRODUCTS 98212 i BELEIVE THEY WERE.
Again I value and respect your knowledge and straight no bs answers .if you have any for me ,I'm all ears
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Old 09-30-2010, 12:41 PM
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Quote:
Originally Posted by sapsz28
Thanks again Eric My mechanic had a client of his abandon a fully forged motor that I just described for you to help me figure out what ci it is. it has a 2 bolt studded bootom end, with a scat forged crank ,scat procomp i beam rods with the 7/16 cap screws speed pro power forged floater pistons,L2489F 30 over flat tops with 2, 4cc valve releifs and an extra 1 cc cut into the eye lid for more clearance,the block alone has $1,700.00 in machine work done to it parts aside,I can pick up the whole assembled balanced package for $2,ooo,what do you think,I'm thinking go for it,could you give me your 2 cents worth please .Thank You.
PS WOULD I NEED A SMALL BASE CIRCLE CAM REGARDLESS OF WHAT i GO WITH ,i WAS THINKING OF THE COMP 12-678-4 WITH THE SPRINGS YOU RECOMMENDED FROM COMPETITION PRODUCTS 98212 i BELEIVE THEY WERE.
Again I value and respect your knowledge and straight no bs answers .if you have any for me ,I'm all ears

The block does NOT have $1700 in machine work. No one does that much machine work and leaves 2-bolt mains. 4 bolt splayed mains would be all but mandatory at that level and for $1700 you can have a fully machined Dart SHP block. Sounds like he's blowing smoke up your arse.
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Old 09-30-2010, 03:11 PM
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Quote:
Originally Posted by turbolover
The block does NOT have $1700 in machine work. No one does that much machine work and leaves 2-bolt mains. 4 bolt splayed mains would be all but mandatory at that level and for $1700 you can have a fully machined Dart SHP block. Sounds like he's blowing smoke up your arse.
I agree. More like $500-$600 in work.
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Old 09-30-2010, 05:03 PM
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First of all, how sure are you of that 3.85" stroke, because piston is a flat top for 5.7" rods and 3.75" stroke crank. Scat does sell a 3.875" crank and a 3.800" crank, but both of those require a 6" rod for the piston to clear the counterweights, and won't work with that piston #....Sounds like a 406 to me.

The $1700 machine work figure is suspicious, I can't see much more than 1/2 of that, including balancing, if it doesn't have splayed caps on it. I'd want to verify it is in fact a forged crank, and not a Scat cast, for that money. If that $2000 price is just the short block,... no cam, t-chain w/cover, oil pump, pan, pick-up, balancer, flywheel then it is rather high, especially if the crank turns out to not be forged.

It is quite likely you may need a reduced base circle cam with this, I can't say for sure as I haven't used that exact rod in one yet. I have heard they have more clearance but I personally can't say.

What all would you be getting for that $2000, right down to every piece??
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Old 09-30-2010, 07:02 PM
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420 block

Thanks for the advice but I was privvy to the invoice which showed everything done to the block and parts from the machine shop such as having the block decked new cam bearings ,main bearings, new bronze frost plugs installed, it was align honed ,bored .030, the crank was cut 10-10,it was torque plated, magnafluxed ,hot tanked baked ,shot peened the rotating assembly was balanced ,,the crank was knife edged,mallory was added to the middle counter weights to prevevt flexing at higher engine speeds ,I plan to rev this motor to 6700rpm max,the block had all the rough edges smoothed out and the oil return holes enlarged and the sand traps smoothed out, as well as the eye lid of each piston was cut deeper by 1cc for xtra valve clearance ,and up here in Canada we pay an average of 2.5 times more for automotive parts,how about 569.00US$ for comp pro magnum roller rockers or 12.00 a quart for compcams oil, and labour regardless of the origin or purpose ,as well my mechanic I've known for 37 years and he married my sister ,so I have a tendancy to beleive him.
that is how the price arrived to where it came to,again I was looking for advice but for some unknown reason, every time time something sounds unreasonable to many of you ,right away you start to critisize and get negative and insult people like me who are looking for a liitle advice from guys like you, why.Is it so wrong that by chance I came across a good deal that does not happen every day.For god sakes man instead of telling me what to look for I get metapfors such as smoke being blown up my rear rather than good for you but be carefull ,or look out for this,or check out for that .
which brings me to my original question do I or do I not need a small circle base cam ,I trust your advice more than a marketing departments of a cam company ,sorry for looking up to you guys for advice.I'D ask my brother in law but hes gone 17 days for moose hunting and I'm stockpileing parts to make the final build easier with the parts here waiting,before I go fo back surgery.
If you dont want to answer my question just tell me straight up ,so we dont waste eachothers time,
we measured the stroke with a mic and it measured 3.85 inches at bdcon the top of the flat top versus the 4.155 bore and it is not a scat crank ihas 5.7 rods with 5/16 and 3/64 ring lands but tha journal spacers are different from anything my mechanic has senn .I can only tell you what I've seen, soory to waste your time .good bye.

Last edited by sapsz28; 09-30-2010 at 07:11 PM. Reason: forgot to add parts
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Old 09-30-2010, 08:21 PM
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The base circle largely depends on the rods. Call the rod manufacturer for their advice. If standard oem rods then yes.

If that's what the machine work cost then way too much money was put in that block. Its not worth that much- not when a fully machined SHP block s less.
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Old 09-30-2010, 08:43 PM
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Didn't realize you are in Canada with the higher costs involved. If someone paid a shop for all the clearancing and clean-up grinding I can see how the bill got so high, especially in Canada.

With the info you added, yes is is possible with offset grinding and machining some off of the piston top to come up with a parts stack that will fit. It is just a lot of work for a small cubic inch gain so that is why I questioned the crank stroke at first. With the info that mallory was added it completes the picture because the counterweights would have had to have been trimmed to clear the piston pin boss at BDC and thus mallory would have been needed to get the weight back.

A question - Was the stroke measurement taken with a depth mic at BDC, and then again at TDC and then the one measurement subtracted from the other(correct way)??...or just measured down at BDC from the top of the block and thats it?? Reason I ask is the second method doesn't make allowance for piston to deck clearance at TDC. It is much more likely that a 3.800" stroke was used, it is common, mostly in Sprint cars amd Modifieds, but 3.85" would be some kind of oddball or custom, or offset ground from a damaged crank in order to make a usable piece. If you can still read the part # on the top of the 2489 piston, there is no way it is 3.85" stroke, you won't be able to get the head on it. 3.800" will just fit.

Either way, 3.800" or custom 3.85" stroke, you can pretty much plan on needing a reduced base circle camshaft, the 3.75" stroke is a tight fit at cam to rod clearance, so anything more will just make it worse. All the cams I have ever seen from 410 Sprint car 3.800" stroke engines were all reduced base circle(but they were all solid roller). If you just go ahead and order it reduced, you can save having a nasty surprise when you do fit it up, rather than getting info from someone that they "think" the standard base will fit...and then it doesn't. If you already have the cam in standard base, all you can do is try it, at best it is fine, at worst you are ordering another.

Factoring in the Canadien factor, if you trust the work is done correct, it is a good deal. Just be sure of what you are looking at, measure all you can if possible.
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Old 10-01-2010, 08:21 AM
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3.80 or3.85

Eric I did not mean to disrespect you or your knowledgeable experience,yes i can read the top of the pistons because thet are brand new as well as the scat rods.The only part that is not new is the crank which was fully checked and cut 10-10,after measuring your way the stroke comes up to 3.80 as you had suspected.Thanks for your support.
PS in 4000lb Z28 with am-21 and 3:42 out back and 041 heads that flow 243cfm with 2:02-1:60 (I know but my budget limits me to that,I'm relying on torque more than rpm) my first one is going tocollege next year so necessity dictates,I have 7/16 roller rockers, any cam suggestons,solid or hydraulic up to 6500 rpm,Thank You.
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Old 10-01-2010, 12:53 PM
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If you want to street drive it a lot with decent manners, your original cam pick still sounds pretty good. going bigger is going to give away to a choppy idle, worse vacuum and mileage.

If you were wanting a more street racer/track type car(heavy hitter street car) then I would say use a bigger cam, but it means more rear gear, big carb and intake, big headers. Might be more changes than you want to make or a rowdier car than you want.

I would definately run a solid cam, more power than a hydraulic, if you can handle a valve lash check twice a summer, and a couple close together after cam break-in. It's not hard, think of it like an afternoon spent waxing the paint - a relaxing time spent with the car on a weekend afternoon.

If you do decide to go with a solid, definately spend the extra for the face-oiling lifters(tiny hole EDM machined or laser'd in the face to constantly oil the cam lobes) and use a oil that contains ZDDP(I like Valvoline WR-1) or add a ZDDP additive.
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Old 10-01-2010, 09:09 PM
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Time For A Change

i PLAN ON GOING WITH A COMP CAMS XS282S,COMPETITION PLUS 28212 SPRINGS,1 PIECE .80 3/8'S MAGNUM PUSHRODS, I ALREADY HAVE GUIDE PLATES AND i HAVE 7/16'S ARP STUDS WITH HARLAND SHARP ROCKERS,MY BUDGET IS $1000.00 AND THE LABOUR IS FREEE,I HAVE A 800 CFM EDELBROCK CARB ,1/5/8 HEADERS WITH A 2/1/2 FLOWMASTER FULL H PIPE EXHAUST WITH 40 SERIES 2CHAMBER MUFFLERS .
GOOD OR NOT THATS WHAT I HAVE PLANNED OUT,RIGHT NOW I'M RECOVERING FROM 3 DISCS BEING FUSED RIGHT AFTER THE HOLIDAYS WE START WORK ON THE MOTOR,THEN RE AND RE IN THE EARLY SPRING THE LIFTERS ARE AS WELL FROM COMPETITION PRODUCTS WITH THE EDM OIL HOLE AND I ALREADY RUN VALVOLINE VR-1 10W30 WITH COMP CAMS Z ADDITIVE.
tHANKS AGAIN ,AND i'LL LET YOU KNOW HOW IT TURNS OUT.thanks for your help.
Ps I know my typing sucks shoudn't have dropped typing in grade 9 oh well live and learn.Thanks Again.
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Old 10-01-2010, 11:19 PM
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Hi ericnova72. Thanks for the information that you had given. This is very useful to me and I will not get rid of finding the formulas. Thanks.
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Old 10-04-2010, 03:26 PM
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406 formula

Well Eric once again you are correct ,yes the depth of the piston at bdc was3.80 inches.Minus the .005 in the hole at the top ,what would that give me 3.75 or 3.775I'm all confused I'll wait for my brother in law to come back ,and just order the basics oil pan pump gaskets timing chains etc,Thanks Again.
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Old 10-04-2010, 03:59 PM
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Quote:
Originally Posted by sapsz28
Well Eric once again you are correct ,yes the depth of the piston at bdc was3.80 inches.Minus the .005 in the hole at the top ,what would that give me 3.75 or 3.775I'm all confused I'll wait for my brother in law to come back ,and just order the basics oil pan pump gaskets timing chains etc,Thanks Again.
3.800" minus .005" would be 3.795". With .002-.003" rod bearing clearance.001-.0015" piston pin clearance in both the rod and the piston and allowing for .001-.0015" difference in rod lengths from blueprint dimensions(manufacturing tolerance) I can see how this would seem to equal 3.795" stroke when measured, but I would be willing to bet it is the fairly common 3.800" crank many circle track engines use.
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