Question: RPM Air Gap Porting

General engine tech -- Drag Racing to Circle Track

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steve cowan
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Re: Question: RPM Air Gap Porting

Post by steve cowan »

skinny z wrote: Mon Dec 06, 2021 12:35 pm
steve cowan wrote: Mon Dec 06, 2021 12:31 pm they do not say what cubes and or AVG CSA of cylinder head,the statement is misleading in my opinion
Sorry about that. In my editting, I excluded that this poster was working with Vortec heads on CID from 350 to 383 to 400 (although 400 was later described as not ideal).
Not a problem Kevin
What I will say is I know a couple of guys off this forum who have engines in the 355-383 range,they design the induction system to peak around 6500 rpm
It's because of application, gearing and maintenance, if you make peak at 6500 you want it to carry past peak and not fall off badly of course it depends on application,the airgap does not have the CSA to do this,the super victor as cast is not the best intake without plenum work but you have to look length and AVG CSA the 2 x manifolds in discussion,not saying the airgap is bad cause it ain't, I have used and tested against a as cast victor jnr and the single plane was faster at the track.i personally think in your application the airgap will work fine.
steve c
"Pretty don't make power"
skinny z
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Re: Question: RPM Air Gap Porting

Post by skinny z »

Really what I'm doing is trying to maximize what I've already got going. Aside from a little engine carnage, I would have already tried, tested and been done with this a couple of years ago.
But circumstances....
That's why the question has been posed and I'd say, been answered more or less. Work with carb spacers once the rest is sorted.

As for better or best for my application, I think I had the answer to that at the outset. It's not an RPM screamer by any stretch. I'll say peak HP RPM should fall between 6000 and 6200 if the simulations are close. And which way I lean towards with the cam spec. With only 355 CID to feed, the dual plane doesn't look to be a choke. And what's more, considering the amount of time it'll spend plowing through 1st gear on race days, I'll use all of the low speed torque I can get.
Then maybe one day a spec converter. Struts and shocks. Etc.
Kevin
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Re: Question: RPM Air Gap Porting

Post by rapidride2 »

Don't sleep on the Vic Junior.
RevTheory
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Re: Question: RPM Air Gap Porting

Post by RevTheory »

I've thought about rounding the leading divider edges, doing my best to get a decent radius from the plenum into the runners and making sure the alignment into the head isn't terrible but I have no idea if there's anything there. I'm definitely getting the carb off the pad with a 1.5 inch, tapered spacer.
skinny z
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Re: Question: RPM Air Gap Porting

Post by skinny z »

RevTheory wrote: Thu Dec 09, 2021 7:10 am... making sure the alignment into the head isn't terrible...
This is something I attempted to do a while back but getting a visual is difficult. I'll have to go for the "transfer method" via a gasket and grease. Something I believe DV prescribed in his Holley book.
RevTheory wrote: Thu Dec 09, 2021 7:10 am I'm definitely getting the carb off the pad with a 1.5 inch, tapered spacer.
This seems to be a common theme.
I'll certainly give that a go when I get back to the local test and tune days.
Kevin
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