Author Topic: 434 sbc build  (Read 1134 times)

Offline tcoupekyle

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434 sbc build
« on: January 18, 2021, 06:32:07 AM »
As things progress in this budget build Iím putting together of a plethora of used parts I have questions.
Primarily about piston choice. The other questions are more of a side note at this point I suppose.
What I have is.
AFR 227/235 65cc chamber 23* heads
Dart little m block- I was told itís zero decked. Came with Ross 18* Pistonís
4 inch stroke eagle crank
6Ē eagle H beam rod
What piston should I run? I also have....
8/71 blower and enderle injection
Plan to run on alcohol. In FED 1500ish lbs
Just wanna go relatively fast, relatively cheap. But trying to balance reliability in there somewhere too. Weighing the options. But I do need a piston for this combo.
Any advice, recommendation? Any off the shelf options? Iím hearing stay under 11:1 with the blower?

Also, I have a set of Zoomies with what appears to be stahl pattern but the center tubes, seem like they are upside down the bolt in the center is on top. Can I just flip over a normal adapter?
All this being said any recommendation on a cam choice?

Offline tcoupekyle

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Re: 434 sbc build
« Reply #1 on: January 18, 2021, 06:34:06 AM »
Also, how necessary is a front crank support on something like this?

Offline denverflatheader

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Re: 434 sbc build
« Reply #2 on: January 19, 2021, 07:11:45 AM »
tcoupekyle - this is just my general acquired info, all the camshaft companies have a supercharger line and you will notice similar specs.  They all promote wider lobe separation angle (LSA) over a NA engine and for those of us that abuse our supercharged engines with higher rpms, you may want more exhaust lift and duration over the intake.
 
The wider LSA is to minimize overlap measured in degrees.  When the intake and exhaust valves are open together (aka the overlap), exhaust back pressure could reduce intake pressure from the supercharger.  You will see LSA of 112+ itís generally recommended not go over 30 degrees of overlap.

The reason supercharger cams typically have more exhaust lift and duration is to more clear the cylinders of exhaust gas to make room for the incoming charge.  Itís just makes it more difficult for the supercharger to work with exhaust taking up space in the cylinder.  I think (generally) up to 8-10 percent higher exhaust lift and duration over the intake is pretty common now.

If you are going to abuse this 434, you are going to abuse this engine, right : ) as a starting point look for a solid roller cam with LSA over 112 and has more exhaust lift and duration then intake.  Alan

p.s.  I like Crower cams, Schneider cams, Isky cams and 43 years ago my first racing cam was Lunati.

Offline tcoupekyle

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Re: 434 sbc build
« Reply #3 on: January 19, 2021, 02:56:08 PM »
Right on! Yes this thing definitely gonna get abused. Iíve been looking at Crower cams definitely a solid roller model. Thanks Allot Denver


Any feedback on front external mounted crank supports?

Offline JEFF/21C

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Re: 434 sbc build
« Reply #4 on: January 19, 2021, 06:35:24 PM »
I had a bbc snout with double key way 30% over 6/71 mooneyham on alky  no support no problems
as for a cam schiender roller worked well

Offline Finnish Fireball

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Re: 434 sbc build
« Reply #5 on: January 20, 2021, 01:33:34 AM »
It is kinda common practise and widely agreed that serious blown SBC needs either BBC snout or external support, and double keyway ofcourse.
I'm fast. I can make five mistakes while others think.

Offline tcoupekyle

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Re: 434 sbc build
« Reply #6 on: January 20, 2021, 06:53:04 AM »
Any options on the support that are recommended besides the rcd?