13:1 427

hi i am building a talldeck 427 it has a forged crank kb 45cc dome pistons should be about 13:1 572 lift voodoo cam dart intake 850 demon carb and i was wondering about what hp it should be and if nos would be safe thanks!  

what type of heads are on it are they ported as well as the valve size what type of valve job was done on the heads standard, 3,5, or 7angle.  
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cast iron oval port 2.06 valve 113cc cumbustion chamber shaved .010  

oh and there not ported and have a standard valve job  

What's the casting # on the heads? Combustion chambers sound too big for a closed chamber, and definately too small for an open chamber.No matter what heads they are, you lost out on a lot of potential power by not blending the valve bowls and cleaning up the ports. A cam with .572 lift will not perform to it's potential with 2.06 intake and 1.72 exaust valves. What stroke is the crank? Rod length?  

well the motor is still in pieces so how much power are we talkin. and the rod's are 6.535 h-beam head casting #336781 336781 1973-85 454 Open 113.0cc  

and a 3.76 stroke  

At least 30 hp can be had simply by bowl blending the valve pockets, and this takes nothing more than your time. At least 30 hp can be had by adding the 2.19-1.88 valves in place of the 2.06-1.72. The use of the larger valves will do three things. First, they have the breathing potential that your .572 lift cam is going to need. Second, a Manley stainless valve with undercut stem is much lighter than the stock valves and that means more valvetrain stability and rpm potential. The third, and possibly most important is the larger valve will regain the proper seat height. Used seats get pounded in over time and a valve job on an existing seat will only "sink" the valve further. This really hurts flow, as well as making the combustion chamber bigger. 781's have great potential as street performers. I have worked with many. But unless you have something I've never seen, they all had 121-123cc combustion chambers. Add in a .040 composition gasket, a -.020 deck height and compression and quench are out the window. I just did a set of 049's for my next bigblock. They are very similar to the 781's. Comb. chamber volume was 121 cc's. Added 2.19-1.88 valves without dimples and brought it down to 118. Ground around the larger valves to unshroud them, and was 119.5. Cut .015 from the deck, and was at the target size of 118. Zero deck the block, and with a .040 head gasket, you have perfect quench.  

13.1 427! you can make serious power with that It will be in head selection and your cam choose wisely. Not sure about those stock heads if they will make any power they might ported setup correctly but might not be worth the hassle. oh and nos on top of that can anyone say possibly very dangerous! you will want somesort of a forged assembly and a nitrous cam  

My 049 heads, on my latest 454, naturaly aspirated, with the same details I described above and 10:1 comp. makes 584 flywheel HP.@ 6000 and 572ft lbs torque @ 4500 rpm. Not bad for "stock heads".  

572ft lbs of torque is not bad,  

The setup you have should make around 520-530HP and if you go with 2.19/1.88 valves pocket port the heads and a 3 angle valve job you should push close to 600HP.  
Professional hi-performance engine builder

Horsepower sells Engines and torque wins races.

ys the 049's flow decent ported