internal balancing OF 383AND POWER , OR ROUGH QTR MILE TIME
 

I AM BUILDING A 377 FROM A STD BORE 350 3.75 STROKE AND A 6 INCH ROD. I HAVE A STEEL CRANK ,SIR I BEAMS ,AND FLAT TOP , ZERO DECK HEIGHT ,WITH 215 IRON EAGLES,
ANYWAY I AM WANTING INTERNAL BALANCING,
SINCE A 4 INCH BORE PISTON IS LIGHTER THAN A 4.125 PISTON BUT A 6 INCH ROD IS HEAVIER THAN A 5.565 STOCK ROD (POSSIBLY).
. IF I TAKE MY ASSEMBLY TO MY MACHINE SHOP WITH A 350 BALANCER AND FLEX, SHOULD THEY BE ABLE TO INTERNAL BALANCE IT WITHOUT MAJOR MALLORY EXSPENSE.
MY CRANK WAS A STELL CRANK FROM A SPEED-O-MOTIVE ENGINE AND WAS BALANCED EXTERNALLY TO A 5.7 ROD 406 ORIGINALLY.
DO YOU GUYS THINK MY CRANK COUNTER WEIGHT ARE POSSIBLY HEAVY ENOUGH TO MAKE THE BORE SIZE DROP BUT PISTON INCREASE?
ALSO IF ANY OF YOU GUYS HAVE A GREAT RUNNING 383 I WOULD LOVE TO HEAR THE POWER THEY MAKE AND TIMES THEY RUN ON MOTOR ONLY

IF ITS NOT TO MUCH TO ASK WHAT TYPE OF POWER CAN BE EXPECTED FROM THIS COMBO WITH A 268 278 @.050 AND 567 587 LIFT SOLID ON A 106, VICTOR JR INTAKE 4500 CONVERTOR ,4.10 GEAR AND IN A 3000LB S10..
THANKS FOR THE ADVISE

Considering you didn't say what heads are on it or how much compression, I'm going to confidently say it'll make at least 250 HP.

215 IRON EAGLES UNTOUCHED, 64 CC CHAMBERS AND 205/160 ,, 10.9 TO 1 COMP , 850 DP
THANKS

Re: internal balancing OF 383AND POWER , OR ROUGH QTR MILE
 

First of all it will not internal balance without lot's of problems, no matter what rod's and pistons you have, so just find an external balance flexplate and balancer, then have the assy. balanced with them.
With the iron Eagle heads it pretty easy to make 450HP, but not a lot more without some work.
I would say you are building a nice street motor, but don't donot expect better than 12's in the QTR. mile if you can hook it up.

JMO

Zip.

thanks zipper
I ALSO HAVE A SET OF 64 CC 230 IRON EAGLES INSTEAD OF THE 215 'S
I THOUGHT THE 230 WAS TOO BIG FOR MY COMBO. I ALSO HAVE POSSIBILTY OF RUNNING A LARGER SOLID POSSIBLY ROLLER ... WHAT ARE YOU THOUGHTS.
I WAS NOT HAPPY WITH THE AFR 210 CNC PORTED HEADS,
I HAD A 406 5.7 ROD FLAT TOP 268 278 @50 WITH 567 587 LIFT ON A 106 WITH 292 GM HEADS IN A 73 CAMARO THAT RAN 11.40@118 ..
WHY WOULD IT RUN SO GOOD BUT A 215 IRON EAGLE BE SO WEAK. IM JUST SHOOTING FOR OPINIONS .
THANKS GUYS FOR THE HELP

I had a friend that ran iron eagles 230's on a 383", but with compression and about a 630 roller, it would run 6.70's/10.90's in a 3,000lb car and ran good. There was nothing done too the heads. He has since gone to alum heads and a 350" it runs about the same. All this on gas with a 750 double pumper. They are probabely the best iron heads on the market in my opinion.

Zip.

Internal Balance of 383
 

I will not address the power question. The term "steel crank" can be misleading. Aftermarket manufacturers advertise their cast cranks as "cast steel", and is often misinterpreted as a forged crank. The aftermarket 383 cranks are based on the Chevy 400 cranks, although cast with better material, the counterweights are designed to clear a 5.550"rod. The factory rotator was designed to fit the confines of the production block. Therefore, the long stroke and short counterweight dictates external balancing. Internally balancing a cast crank with the lightest components is a chore and costly. The front of the crank can be corrected with heavy metal but the problem is with the back of the crank. To properly locate the H.M. you will have to drill through the wing on the flywheel flange and due to the short counterweight, you run the risk of getting to close to the flywheel bolt holes. The balancing cost far exceeds the price of the crank (if cast). The 4340 aftermarket forged cranks can be ordered for a external or internal balance application. I know the balancing question was answered. I wanted to offer an explanation.