SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: Rogers Hopeful on September 02, 2016, 10:03:20 AM

Title: Repowering!
Post by: Rogers Hopeful on September 02, 2016, 10:03:20 AM
well the small block pushed a valve guide and since i have the means to repower I went to a drag racing buddy of mine to build me a 434 SBC.  He's expecting 550-600HP (old motor was 325HP trying to push a SS A impeller).  And its done.  All new parts from the pan up.  The 16'6" rogers should scoot pretty good now!
Title: Re: Repowering!
Post by: Rogers Hopeful on September 02, 2016, 10:06:10 AM
one more
Title: Re: Repowering!
Post by: GT Jets on September 02, 2016, 11:04:51 AM
What kind of RPM are you needing to make that power? You're likely going to need to cut the impeller down a half to a full trim.

JMO
Title: Re: Repowering!
Post by: GT Jets on September 02, 2016, 11:06:01 AM
I think you may fall short on torque.

That thing's looking mean.
Title: Repowering!
Post by: Rogers Hopeful on September 02, 2016, 12:06:39 PM
What kind of RPM are you needing to make that power? You're likely going to need to cut the impeller down a half to a full trim.

JMO

He said the way he was going to build it, was so that the power was going to come down low. Said it won't be a super high revving small block.

Most 434 sbc builds have peak HP and Tq between 5300 and 6000 rpm


Dreaming of the river
Title: Re: Repowering!
Post by: GT Jets on September 02, 2016, 12:39:05 PM
Can't wait to hear about how it runs.
Title: Re: Repowering!
Post by: Rogers Hopeful on September 02, 2016, 02:36:57 PM
I don't know a lot about cam specs. But these look healthy.
300-308° .565-.580
245-253° @.050
110° lobe center.


Dreaming of the river
Title: Re: Repowering!
Post by: steves86ta on September 17, 2016, 04:41:01 PM
I'm curious how it runs too. I have ran those heads before and didn't like them but it was a bad combination anyways.

434 is a lot of cubes for a small block. But should be a runner

Do you know what it did before? What rpm did you turn that A?
Title: Re: Repowering!
Post by: steves86ta on September 17, 2016, 04:41:27 PM
That's a bit of duration, but not much lift. I would think it would make some good torque

But I would imagine that duration would want some rpm.

Mines only 235/242 and it's just barely coming alive at 5k. Almost sounds like it is missing at 2500 or so. In a car the cam guy wants my combination shifted at 7800
Title: Re: Repowering!
Post by: Rogers Hopeful on September 17, 2016, 11:20:28 PM

I'm curious how it runs too. I have ran those heads before and didn't like them but it was a bad combination anyways.

434 is a lot of cubes for a small block. But should be a runner

Do you know what it did before? What rpm did you turn that A?

I gave my engine builder full reign on what to do so he made a 383. Still gonna make 550-600 hp. 
The old motor only spun up to 4500 rpm


Dreaming of the river
Title: Re: Repowering!
Post by: steves86ta on September 19, 2016, 04:57:32 PM
I gave my engine builder full reign on what to do so he made a 383. Still gonna make 550-600 hp. 
The old motor only spun up to 4500 rpm


Dreaming of the river

So it ended up being a 383 not a 434?
Title: Re: Repowering!
Post by: Rogers Hopeful on September 20, 2016, 03:10:55 PM

So it ended up being a 383 not a 434?

That's correct. He was worried about the steam holes and sand build up in the 400 block.


Dreaming of the river
Title: Re: Repowering!
Post by: steves86ta on September 21, 2016, 01:06:49 PM
That's correct. He was worried about the steam holes and sand build up in the 400 block.


Dreaming of the river

sounds good. Im curious how it runs!
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