thanks griff, i spoke with the tech at summit, he says i will only get like 300lbs of torque because of the dished pistons. that just doesnt sound right to me. and of course the cam is to big for vortecs. i was expecting ( hoping for)alot more torque than that. there is a smaller cam revs to 5500 rather than 5700 capatable / vortec ill look a little deeper in that direction also check out cranes cam card thanks again 359 pete

 

I was thinking about this a little and I think we can figure out more if we knew the piston spec. Is there a name or part # on the piston. Can you get a picture of the piston and post it maybe someone can match it up. Question for the machine shop guys.. is there a way to measure the piston volume like you would head volume?? Once we have this we can figure out the compression ratios, static and play with the dynamic on cam choice. 300 ft/lb is bs foryour 400 by the way.

 

checked out cranes cam reccomendation. they suggest using part# 113522 cam kit 218/230 @ .050 .459/.486this is their Z cam . the .486 is what im worried about. smaller cam may just have to be the answer.THANKS 359PETE

 

The cam recommendation they gave is a split duration cam they try to compensate for the less flow of the exhaust by increasing lift and duration of the exhaust. The exhaust flow is weak when compaired to the intake in the vortecs. This is what we are doing with our budget 350 we have a 270 magnum cam its a single duration .470 lift cam we got a set of the vortecs stock used. To use the cam we figured we would just port the exhaust side mild port cleanup contour the valve guide and slightly increase the throat area just cleanup the intake these heads already have 3 angle valve job stock(except certion 906 castings with the hardened valve seats) I am getting a little stronger springs and through the measurements I already mentioned I need .010 additional clearance being the backwoods mechanic I am I sanded .010 off the backs of the retainers to get the clearance. There are several other ways to handle the clearance issue 1) take it to the machine shop have the guides cut down with new seals $100 2) beehive springs and special retainer $200 3) there is a guy selling umbrella seals on ebay for $40 with springs(not to sure on this one) 4) sand down retainers (very minimal gain) but should work for us $ emery cloth. 5) buy the cetter and do them your self $80 If you find it necessary to go to bigger springs the spring pockets need to be enlarged comp makes a cutter or a machine shop could do it.I could go on and on but just to tell you I assumed a 12cc dish on your pistons and ran the 270 comp cam on desk top dyno and found your torque to be in the upper 400ft/lb range at 3500 rpm just got to love the 400....

 

found out it is possible to grind a litte fat off the bottom of the retainers to gain the clearance i desire. what do yall think of this idea.359PETE

 

what is a pc seal cutter and where do i need to go to get one? 359 PETE

 

Summit Jegs also called valve guide cutter, you might also consider valve spring cutter for bigger springs. Here is a tread where they discuss options I think they have a section for vortec heads http://www.nastyz28.com/forum/showthread.php?p=534999

 

I recommend lowering the valve guides to allow for the extra lift. The retainer hitting the seal and or guide will cause a lot of headaches!

 

Thanks for the compliment! I really do appreciate that. It looks like a missed a lot over the past week.

 

It is not the way to go. You want to lower the guide and not touch the underside of the retainer.