Vortec 355

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rocketracer380
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Vortec 355

Post by rocketracer380 »

Is 450 hp attainable from stock 906 vortecs 10:1 comp
rebelyell
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Re: Vortec 355

Post by rebelyell »

Yes.
Wider seat & face angles, Great valve job. Carefully chosen cam.
See build threads by S-T member CGT, project Dale.
mag2555
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Re: Vortec 355

Post by mag2555 »

Yes.
In stock form they flow 235 to 240 cfm @28”@ .400” lift, which if you open the valves on average to that lift you could make well over 450 hp, so winning the game means running more like .550” lift so you have those average flow numbers!

The best way to do this average.550” lift depending on your motors cid maybe with higher ratio rockers.

The Cam and merge type Header collectors and collectors of the correct lenght will be very important here in producing VE numbers a tad above 100% also since you only have a 10 to 1 compression.

You do not want the motor to have to work much at pumping out the exh which can be the case with only a 10 to 1 compression.

You’ll know your Cam pick is in the Ball park if your hot cranking compression is at least 165 psi.

If your running a duel plane intake and not limited to Carb size then you want to stay on what would be called a tad on the big side if you want your hp numbers to not nose over too fast above 6200 rpm.

A in the Ball part way of figuring out potential hp numbers from flow numbers taken at 28” is as follows.
Flow @28” = 235 cfm
235 x .598 = 140.53
140.53 x .43 = 60.43
60.43 is the potential hp per cylinder that could be made.
60.43 x 8 = 483 hp.
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F-BIRD'88
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Re: Vortec 355

Post by F-BIRD'88 »

062 vortecs flow 228 cfm stock.
mag2555
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Re: Vortec 355

Post by mag2555 »

Unless my eyes are deceiving me the op posted he has the 906 casting .
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1980RS
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Re: Vortec 355

Post by 1980RS »

rocketracer380 wrote: Sun Apr 25, 2021 1:59 am Is 450 hp attainable from stock 906 vortecs 10:1 comp
Yes, I ran 2 different sets of Vortec's last year on a 406. One set stock with a 3 angle valve job only and the other set mildly ported. 1st set was in the mid 11's and the other set went 10.90's very easy. My 9:1 358 runs 11.30 with Sportsman II heads but I think the 062's would give them a run for their money for sure. Run the Vortec's you will like the power.
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