Keith Black piston question • The Dodge Challenger Message Board

by **Adrian Worman** » 06 May 2009 18:31

Hello mates,
I just ordered a set of Hypereutectic pistons pt.no.KB236 cos they have a 1.8cc step on the crown and I wanted to get a bit more compression. At present I am using a pair of 90cc motorhome heads casting 452 and I did'nt want to mill the heads to raise C.R.
What swung me was trying to take advantage of the quench area, I had seen info on this and thought it was an important factor in planning a build that I'd previously dismissed.
One major flaw in my plan that I can see is if I wanted to install a pair of Stealth heads I'd have to be milling the piston crowns. Bugger.
Any ideas?
Adrian

by **Eddie** » 07 May 2009 14:34

Adrian, What are you planning for,, with this engine? Street, dual purpose, street strip, or my favorite---endurance racing,(fleeing the coppers). :lol:

And has the rotating assembly,(pistons, rods, bearings, rings, , ectt been professionally weighed& balanced? Have the cylinder's bores been honed to the pistons? Your cast pistons,(KB236) weigh 916 grams, stock was around 1100 grams. A flat top forging can bring this down to 700,, you have a few options here, but I'll wait till I recieve your answers.

by **dave-r** » 07 May 2009 15:52

I think they are the pistons I use with my 906 heads. With the raised "D" to fill the quench area?

I had to use 20thou steel shim gaskets to get the 40 thou quench.

I think I have a little over 10:1 compression ratio with these.

by **Adrian Worman** » 07 May 2009 18:41

Can't answer much Eddie cos most of its still in your country waiting to be dispatched. Was aiming for nice and simple street rebuild; replaced .484 cam with Comp Cams Xtreme .507/.509, mildly ported 452 heads, 1.8cc step KB pistons, Sealed Power filefit moly rings, '72 440 HP block just bored .030"plus, existing steel crank and six pack rods (the same ones you helped me find .040" and .030" bearings for) and a windage tray and topped off with a dual plane and an Eddy 750cfm.
The pistons do have a D shaped step Dave, ta for the info on the Painless kit, just ordered one.
Cheers, Adrian

by **Eddie** » 07 May 2009 20:27

Adrian Worman wrote:Can't answer much Eddie cos most of its still in your country waiting to be dispatched. Was aiming for nice and simple street rebuild; replaced .484 cam with Comp Cams Xtreme .507/.509, mildly ported 452 heads, 1.8cc step KB pistons, Sealed Power filefit moly rings, '72 440 HP block just bored .030"plus, existing steel crank and six pack rods (the same ones you helped me find .040" and .030" bearings for) and a windage tray and topped off with a dual plane and an Eddy 750cfm.
The pistons do have a D shaped step Dave, ta for the info on the Painless kit, just ordered one.
Cheers, Adrian

I would just use your existing heads with the flatter intake ports,(A plus there), and most likely induction hardened exhaust seats for use with unleaded fuel and no worries about exhaust valve seat recession. Dave's 440 is similarly built I think from reading his build, and it runs very strong! Sure you may pick up a few more top end ponies with the 'source' heads but the torque will be darn near the same with your KB quench dome pistons and open chambered 452 heads which have been modded and should flow a decent amount at the lift of your cam. It will be a strong runner I'm sure and produce gobs of low speed torque. For the extra money you would have to spend in milling the pistons .070,(as per KB recommendations), re-balancing the rotating assembly with the lighter machined slugs, and the lift of your camshaft selected, it would be all for very little gain in my opinion. I would rather go the different piston route with forgings and ditch the thicker 5/64 ring pack in favor of a thinner less friction 1/16 ring pack and pick up the extra 20-25 ponies from the friction reduction the thinner rings afford. Then select the piston that gives a near zero deck flat top. Buy the 'source' heads and have a bigger camshaft with around 580-600 lift then you can take adavntage of the bigger airflow numbers those heads have. But I think you have a nice combo now and just go ahead and build it,, the Keith Black Pistons are very tough and tight fitting,(less oil contamination and longer ring life due to less piston rocking at TDC) they have very little blowby and reflect the heat of combustion back into the chamber where it belongs. For what you are doing they are the 'perfect' piston choice! It's 'ALL in the COMBO" a 440 with single plane intake, bigger camshaft, bigger intake ports with more volume, bigger compression at the expense of low speed airflow velocity. The other way is what you are doing, smaller cam, smaller intake ports, dual plane it all adds up to much higher velocity and terrific throttle response and torque. Perfect :thumbsup:

Sorry for the winded reply :lol:

by **Adrian Worman** » 07 May 2009 22:22

Ta for that Eddie, at least I know I'm in the right direction. I've still got a another 440 lying in the garage just waiting for a 440Source 500+stroker kit,stealth heads and roller cam, for now I just wanna look forward to actually driving this summer. Your posts and replys are never long winded mate, too informative for that.
Sadly Eddie my '90 Ram dayvan you helped me with has had to go, but I just picked up an '04 Ram van with a 5.9litre V8. I can't beleive a van can have that much performance, it smokes both rears for 50 yards and blows most all traffic from the lights. What a hoot!
Adrian