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piston choice for stroker

Started by flyinlow, March 08, 2021, 12:38:06 AM

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flyinlow

 On a 440 stroker with a 4.150 with flat top pistons with a small valve relief I am looking at CR of about 10.8  with 84cc Mopar 452 heads. Not sure if I want that much. Does a 12 cc dished piston work as well if the  quench height still remains about .050? Assuming the dish is under the combustion camber.

With a 4.350 bore can you unshroud the valve area to lower the CR and help breathing?

Challenger340

http://www.wallaceracing.com/dynamic-cr.php
Depending upon Camshaft events..... sometimes even 11.5 Static is fine

We don't find the dish Piston flamefront as efficient.

regarding 'unshrouding' the Intake Valve..... ALL 'std' BB Mopar Head Gaskets are compatible with the Max Wedge Chambers which are much larger around the valves
Place a Std Head gasket on your Block, and look at the Gskt & Block surface where the Intake Valve is..... then using a set of dowel pins place the same Head Gskt on your Heads on the Bench ?

Only wimps wear Bowties !

BSB67

I think the answers to your questions is yes.

1) if you have the head cnc ported, the chamber will come out to about 88 cc
2) you can relieve around the valves.
3) you can also relieve the block to unshroud the valves
4) you can have a couple of cc's removed from the valve pockets

Elevation matters
Intake valve closing timing matters
Available fuel matters.

Or get a dished piston

I'm at 10.8:1.  93 octane and a pretty late I take valve closing and I'm on the edge of detonation.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

flyinlow

My garage is 1000 feet above SL. Ohio is not that hot, a few 90* + days. Usually 93 octane available ,but  running on 90-91 is a factor. Camshaft choice will be one of my next posts.

Switched to a 4.250 crank ,7.10 rods and a dished piston. CR with my heads is 10.05 with a standard deck.  . With the 10.706 deck height I figured about 10.3 : 1.