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Discussion Starter · #1 ·
i picked up a kieth dorton/holly single plain high rise manifold ..
im currently running a super victor #2925 ..
heres my qestion
the victor manifold on my motor is only match ported my heads flow around 312 cfm #700 .they are brodix track 1's i have a 404 cubic inch sbc , roller cam ,13.5-1 compression that makes about 550 whp on motor that spins to around 7600 rpm before falling off ..(it is a nitrouse motor but i would like to get out of it what i can on motor )

well i bought the holly manifold to put on a spare junker motor im building for a street toy(355 with untouched victor jr heads) .but after picking it up i started to go through it and port and polish it matching it to a 1206 gasket and trying to uniform the runners
ect ..i have reached the bottom of the plenum and im not sure where to go ..i dont want to fuck up the distribution but id like to do what i can ..so far its pretty decent i think ..

#1 what manifold is better out of the box if either for my application 404 ci sbc ..
#2 does porting the intake thouroughly but not excessivly help ..id like to increase velocity and smooth it out but not hog it and destroy it ..
#3 is it even worth trying to switch them with the cfm of my heads ?
#4 am i annoying and should i just wing it bolt it the fuck on and see what happens ....

ha!ha! thanxs in advance guys ...
ill post some pics of it so far im about 5 hours into it
 

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Discussion Starter · #2 ·
here are a few pics






im no porting guru but so far all i have tried to do is smooth the runners clean up the casting marks and raise the runner roof up a bit ..i havent put the head on the block yet to get the runners lined up so ther is no match port yet either ..
 

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Discussion Starter · #3 ·
well i started to spen a little more time cleaning up the runners im all the way through the bottom into the plenum .i did find that there are some spots you just cant get with the grinder so i had to hand port them with emery cloth verry time consuming but the hard to get spots seem to be the tightest and need the most work .i started to scotch bright them for the final finnish i still need to go through one more time and get them dead on but its getting late
.ill finnish tommorow if i have time after putting my motor back in ..
some more pics moving along ive ported qite a few set of heads in the past and they seem to work well ,,but any input on the manifold is welcome ..

pics

runners i was trying to get all the way through but the light screws up the photo ..

 

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The thing I have found on 23˚ heads that do not have major work at the PR pinch do not change much with different intakes or with porting them, The pinch is usually more restrictive than the intake. You can shift the power up or down a little but not much otherwise. Cleanup and port match works well on the Super Victor and is a good manifold with minimal work.
 

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Discussion Starter · #6 ·
from looking at them the holly and the super victor look identical the runners measure the same but the holly has a taller (not by much )plenum ..
and the base of the plenum is slightly different ..i was curiose if these support 312 cfm ?i had the heads on a bench a year or so ago but never did anything with the intake ..

so basically just clean up the castings ?and keep the super victor on the 404 ..
 

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Discussion Starter · #9 ·
thanxs jmarkaudio for the responses ..

running the manifold above on a 355 with 11.5-1 compression ,with victor jr heads (ill have to go through them as well i guess ) and a decent size roller cam is it un realistic to try and expect 500 whp .....

i had a 358 sbc 10-1 make 412 whp with a solid flat tappet cam and home ported performer rpm heads ..can i pick up the other 85 hp in heads ,cam and 1.5 point in compression

thanxs again guys ..
 

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Unless you are trying to run pump gas, bump the compression up. Cam depends on what you have for a converter and gear, as well as how high you want to turn it and vehicle weight. 600 to 650 dyno HP is obtainable with the 404, your Track 1's flow good for what they are.
 

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Discussion Starter · #12 ·
im probably getting confusing with all the info but
my 404 with the track1,s is in a 2800 lb 4 link rx7..
that motor was built by j&e automotive but i was thinking about switching intakes to give it a try ...


the pump gas 355 im asking about will be in a 2700 lb mustang notch
i havent bought a converter but it will have a glide ..i have victor jr heads im going to port them and have them angle milled to roughly 60cc..i want the 355 to be at 11.5-1 for pump gas i was hoping to spin the motor to 76-7800 rpm and get 500 whp
with a still kinda driver freindly 9" converter stalling at around 43-4600 rpm
..is this realistic for a 500 whp goal this is the 1st non power adder motor ive built im looking to weekend drive it as the rx7 is no longer street freindly ..heres some of what i have so far ..the bottom end is now assembled with flat tops and i have the heads im trying to get a killer budget build ..




basically if i cant get 500 whp from this on pump on motor im going to get 76 cc heads and bolt a turbo /intercooler to it .
so thats why im asking so i can build an appropreit 5-600 whp pump gas cruiser
 

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I think you will be able to attain your goals with the 355. Will it have nitrous on it?
 

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Discussion Starter · #14 ·
untill now all my small blocks have run nos ..on the last one that made 412 on motor with rpm heads and a solid flat tappet cam it went [email protected] on a 350 hit and made 750whp ..im trying to get away with it being as much of a motor car as possible if i could run the 10.0 index on motor that would be fantastic ..
but the closer i can get w/o the bottle the better ..
i know some of the ??? are a little redundant but im newer to domestics and even newer than that to all motor settups and what to expect ..

i used to build turbo volkswagons but stopped that about 5 years ago from being tired of the constant trannsmission failures ..
 

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Get rid of the knife edge. It doesn't need to be flat-blunt but rounded rather. Similar to the way it was.

Anything that air or air/fuel mix has to flow over or through needs to be able to find it's own direction as to where it's being pulled or forced to go. Knife edging in single plane intakes takes an exact science to get the desired distribution and results. The sharp edges do not allow the air and/or air/fuel to flow freely where it needs to--the edges give and more or less forces--a direction. On a flow bench where port by port testing and corrections are made, knife edging is most beneficial by directing more air/fuel to leaner cylinders and taking some away from fatter ones. But off-the-cuff knife edging can and will eat power on the upper RPM's.

With no directional flow the air/fuel has a choice of "door #1, door #2, door #3, etc). With the knife edging the air/fuel doesn't get the choices and all you get is what is behind door #4 whether you like it or not.
 

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My intake was ported like his with very sharp edges. I did flow one of the intake ports with and without the intake and it actually increased flow a little in the .500 to .600 range with the intake on. It didn't hust it anywhere else. I am running EFI so it only has air going through it (most of the time). I also spray it with nitrous once in awhile and that is the only time it sees fuel (until I put in larger injectors and do it dry).
 

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Great, you saw an increase on one port, what about the other seven? No, I'm not being sarcastic, I'm being serious.

The pic below is of a engine dyno graph. The only thing changed was the intake was knife edged before and then the edge removed. You'll notice some change (still relatively small) under 6000 RPM's but afterwords, the difference is clearly apparent. It's only about a 10 HP gain but 10 HP can be the difference of win or lose. :)

Pic is courtesy of Pete Harrell @ Harrells engine and dyno.

 

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You would never want a knife edge like that.... the 'Air' might have no problem making the turn or transition around the edge, but the fuel will not be able to stick with the air..... you'll shear the fuel and separate it from the mixture.... The fluid can't make the turn....

So unless you are looking to purposely shear fuel from the mixture, not a wise idea.
 

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Discussion Starter · #19 ·
i didnt knife edge it it came that way all i did was remove the casting marks ..
the super victor is rounded in the plenum although the runner sizes are almost identical (i shouldve taken pics i just had the carb off )
on the super victor the plenum sticks out much further also ,this is kind of why i was looking to try both of them ...or looking for input ..
they seem to try contradicting theorys in the building of the manifolds ive read a few books but no real world expeirience ..
thanxs for all the input guys ..
 

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Discussion Starter · #20 ·
well i just finnished with the manifold i took the edges down and rounded them as best i could as they are only about and 1/8" to a 1/4 unch thick.finnished bolting the heads on and matched it to a 1206 gasket ..
i tried to shape the outside edge of the runer as smoothly as i could to get as much velocity as i could with out getting all crazy big in the runners ...
im going to have to get a day at the dyno soon as i want to try 2 different carbs and these 2 manifolds ..

ill post pics in a bit..
 
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