Thread: 434 sbc

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Back to the soup bowl pistons and quench. A friend bought a 434 sbc at an excellent price. Almost what the sportsman block would cost let alone the 230 Iron Ealge heads on it. The motor is 12.8:1 CR and he wants to get the CR to about 8.5-9.0:1 and set-up with a 177 blower. I got a 420 with 9.0:1 reverse dome with the 177. No one can make the pistons with low enough CR in reverse dome or inverted or D-shape etc., only dished. The engine now is a 427 and he is boring and setting it up for street use on pump gas. 4.0 stroke, 6" rods, Dart block, Dart heads, and all studded. I don't see any way quench would help out in this application. He will run 4-6 lbs boost. Any suggestions?? I have been dealing with piston man. daily and dished is all they willing to do. Not enough compression height for a inverted dome. Has to be a negative 38-46cc recession.

How did blower motors run before inverted dome? Water injection is the only thing I know to run in order to control the furnace without a good quench.

what is the bore of the engine?

have you checked out www.jepistons.com. they have a pretty good catalog in pdf.

You can build this combo. with a 9.325 deck height block.

Thanks men.

The bore is 4.125 now but will be punched to 4.155. No one makes a shelf piston that I need.

Changing blocks or heads isn't cost effective.

We decided to go with soup bowls from Ross. The engine needs rebuilding and must have new pistons so it was in the budget. We have also decided that the only other way to insure a good, long life of the engine without a good quench area will be to go with a water injection system from www.snowperformance.net I am ordering me one also for my 420 and bumping my boost. I been on the phone with Ross and snow performance and we are confident we have a game plan to make plenty HP on pump gas out of both engines. The 434 will run the 4-6 lbs and no more to be safe because of quench. I will bump mine to 10lbs with my quench and water injection but no higher because my block isn't o-ringed.

I have never ordered a one-off custom set of pistons but I have heard of people doing it, in a magazine I dug out it showd them getting a one-off set from Lunati technical support via phone Monday through Friday 7AM to 5PM CST @
662 892-1500.

I would almost bet that most all american piston manufactures can build a set for what ever your heart desires.

Originally posted by dreamrod57
I have never ordered a one-off custom set of pistons but I have heard of people doing it, in a magazine I dug out it showd them getting a one-off set from Lunati technical support via phone Monday through Friday 7AM to 5PM CST @
662 892-1500.

I would almost bet that most all american piston manufactures can build a set for what ever your heart desires.

Custom pistons is easy to order. They just can't put the inverted dome with this setup beause of compression height.

I wouldnt know.
but I was just making a suggestion, sometimes the guy's at those type companeys can help comeup with a salution to your problem.

Im just glad that im not faced with that type of problem.
I wish you luck.

You could probably get some money for those heads, enough money to buy a head with a 72 cc chamber from somebody like AFR. That way you could use your quench piston. Since you're supercharging, those giant intake runners aren't as necessary as on a NA motor. The supercharger can overcome them. The smaller runners will decrease compression pressures, but you can dial up the boost, forcing more air through the small runners, to bring yourself back to the detonation threshold. Detonation occurs when cylinder pressures are too high. Now, you'll make more heat in the intake charge which brings detonation on a little sooner, so you wont make as much power as the big runners with less boost. They do sell intercoolers that fit under superchargers which will fix this. With an intercooled setup and a good quench on 9.0:1, you could probably run upwards of 12 psi of boost and make somewhere around 600-700 hp on gas.