Piston to Valve Clearance?

I am assembling a new engine starting with an .030 over '73 455 block. Heads are TA Stg2 SE, pistons are Sealed Power L2353F-30 forgings (no valve notches) on which I measured the dish volume at 23 cc. Head gaskets are Cometic .027. Block will be milled .018 to get 10.51 calculated SCR with this combo. Rockers are stock ratio 68-69.
Cams under consideration range from TA 288-92H on the small side to TA 290H on the big side, or possibly something in between.

Is there a reliable calculator for piston to valve clearance using the TA published cam specs and the above build specs? If not, anybody know if the 290H will clear with this combo?

 

No reliable calculator that I know of..just a base of knowledge from those checking piston to valve clearance over the years. In an uncut block, it is generally accepted that the TA 413, or similar size cams are the biggest you can go without valve reliefs. In your case, milling the block, I would say that the 288 series is the max size, but also very much recommend that you check both the actual cam specs, and piston to valve clearance. You close enough here that camshaft location could cause an issue.

 

So does cutting the deck .018" get you to zero?

 

I think that there are SO many factors in play here that your best bet is to get some modeling clay, mock up the engine with used head gaskets to get the crushed height, and get a measurement. Then you'll know for sure. I believe you want to see a minimum of .100 on the intake and .080 on the exhaust.

 

by my calcs, I'll be .020 in the hole after decking .018. Not trying to get to zero deck, just looking to get the SCR around 10.5, and use the parts I have.

 

Have you mocked up 4 corners yet? I'd strongly suggest you mock up 4 corners (pistons/rods) and turn it over to check deck height on each corner before decking. I know, royal PITA but worth it. I didn't and went based on "calculations" and still ended up hitting the piston(bigger cam). I had to fly cut the pistons again to gain enough clearance.

 

Good advice for sure. Mocking it up is the only way to really know the clearance, and mocking up 4 corners will tell me how well the uncut decks are aligned before they are touched. Was hoping to avoid two separate trips to and from the machine shop lugging my block, but it would be the best insurance. Advice from Tim at TA is I will likely be ok with the .018 deck cut and cams under about 240 deg @ .050" with my setup, but he also recommended checking to be sure. My current thinking is to go with the TA 288-92H, which is on the milder end of what I considered and should also be a good match with the Stg2 SE heads.

 

Just be sure to have the cam degreed before you check for clearance.