Inliners International Forums General Discussion Hi Performance Siamesed Port

What is the most Horsepower made with a siamesed port, stock, bump port, or whatever ?

Jim Hedrick and Cotton Perry made 550+ N/A (the most I have heard of)
My 37 with a turbo 650+

Everyone now is running 12 ports or V8 heads or 4 valve heads

Just curious, Harry

Guys in Brazil are making 1000-1200 HP

Ask Douglas.
MBHD

douglas, do they use carbs or FI direct port injection, any distribution problems ?

There was as 1000HP here, ported head, bigger valves, big turbo (carburated) and Nitro, lots of Nitro....

i put the link of a video of this car making 8.5-9 seconds on the 1/4 mile!!!

found the link

http://www.youtube.com/watch?v=UflcBRn2iVg

Edy,
I think you are saying he is using Nitrous,not Nitro, correct?

MBHD

Can you keep head gaskets in that thing and if so which one are you using?

Hank

correct! we in Brazil say here "nitro"! i thought in english but wrote it in portuguese! ;-)

Mighty 6, copper w/ ss "o" ring and receiver grove in head, works fine but better not detonate the engine too much!

Harry

Edy-Douglas,
Douglas had posted some pictures of cars from Brazil with turbos most were Power Master TA66'S which flow enough air for about 700+ HP and one with GT45 about 1000 HP. You say some also use Nitrous Oxide along with turbos. Some time ago I had found other pictures of cars,in Brazil,with turbos and carbs.

Do the ones using carbs, one in the pictures did, have any distribution problems with the siamesed port?

Anytime I approach 700 HP, cylinders 1&6 go lean as if 2&5 were stealing the fuel from them. I have read on other sights that other engines with siamesed ports had this problem, and I wondered other than fuel injection how they dealt with it.

I know Hedrick had different cam timming on different cylinders maybe for this reason.

Anyone else have any ideas? Edy and Douglas please ask around if anyone has had this problem.

Thanks, Harry

Harry, what type of manifold are you useing when this happens?

Armond, a log style manifold with a draw through turbo setup or a log style with 3 two barrel carbs one over each siamesed port with a blow through turbo system.
Problem went away when I divided the ports and intake manifold.

Harry

A little confused.
If your fuel distribution problem went away, why are asking how to fix your fueling problem?
Just curious.
MBHD

I'd still like to know what the max output of a naturally aspirated siamese port engine can be. No forced induction, no chemical enhancements. Anyone have some good dyno numbers to share?

Armond,,
Ask Mike Kirby or Glen @ Self Racing,for there HP & torque figures.

MBHD

Armond, Hedricks and Perrys "Pocket Rocket" chevy II from the 70's made 571 HP ran mid 10's @ 125 MPH at 3300 LBS. Most HP I have seen from a NA 292.

Hank, Just curious what causes the problem.
I ploted the cam timming VS piston position and may have found what causes the cylinders to run lean.

Harry

Wow! Now there's a mark to strive for! One can only guess at what train of thought they were on. 319 CFM is an awesome accomplishment with this head. No doubt about it, I have to finish the flow bench!

I always thought the Hedricks and Perrys "Pocket Rocket" was Powered by 292's Not 250s

Armond
whos getting the 319 cfm out of our Cast iron head? Self and them guys? I wonder if that has anything to do with the thing they were/are working on for the top of the Port to get air flowing better around the guide.

250? Nope, 292 was it and the 319 CMF came straight out of Leo's book for Hedricks and Perrys head.

Oh yeah i've seen that i just thought maybe someone else Had started to make them kinda Flow numbers. It would be interesting to know just what all they had done Back then to Kirbys heads.
To get them to kick out those Numbers and at what lift it was.I know Those guys Ran some Killer cam lifts 800 plus.

Mike Kirby has that actual cyl head(the one that flows 319 CFM), they Hendricks, Cotton, Perry went into water passages to recontour (SP) the ports, not a reliable street head by no means.

MBHD

I hear That. I know my motor wouldn't run very well On water. Unless it was Very small injection.
And Now that you bring that Up i think Mike once told me about that head when we were talking about Max cfms from a stock cast iron head.
AND that is really The bad thing When trying to get the Max out of one of Our Heads. Is that If you go to far as In trying to open up the Insides
You can make for some VERY thin Walls.And for a
UNstable head when it comes to Over heating it especaily.

I wonder how they handled the water problem? Did they patch the head where it got too close or did they simply fill the head and do without cooling? Larry, you know how they delt with it?

They broke through(the water jackets) on purpose. They made the bowl areas big.
Then,,, IIRC they brazed it back, the water passages.
Racing 1/4 mile won't heat up too fast,esp,if you are running methanol/alky. Not sure if they were?
If you want to know more,,, Mike Kirby has the answers.

MBHD

Thanks Hank, It always amazes me how much has been done with these engines. Yes, if I need to know more, I'll give Mike a call.

Jim Hedrick ran a normal Kirby-Sissel bump port head that Jim reworked to enhance air flow. Since the car ran modified production class (GAS ONLY) he had to run round robin, no cool down. so the head must have been pretty durable.

The reason I started this post was to try and see if anyone knew of what he had done to his camshaft. I now think it was a distribution issue at high HP levels that he was trying to correct.

Back in the 70's the chassis was updated by Pat Curan Race Cars of St. Louis. At this time Vernon Tracy of St. Louis, an engineer at Mc Donald Douglas, designed the 3 Two barrel manifold with Holley carbs that increased the HP of the engine over the old weber style. My brother and Pat built it, I still have the Die to form the "U" bends to the clyinder head port and Tracys paper work with velocities, flow numbers etc. My brother remembers that Hedrick had said something about the camshaft being different one clyinder to the other.

I ploted the cam duration VS piston position to try and find the reason, and may have found it!

Mike Kirby said that "special camshaft sounded like crap(sounded like it was missing really bad) when idleing,but when it was wide open it sounded great.

Making an odd timed camshaft is not new,there are import siamesed cylinder heads, I need to research & get back to you.
If you want to get info from my friend on this type of "special" camshaft he will give you the low down.
Getting a camshaft made as a one off will cost quite a bit.
Ask for Dave @ West Coast cylinder heads 818 705-5454,or email him on the forum here, Westcoast dave

MBHD

Harry, this plot sounds very interesting... I've done a similar one before, but considering single-cylinder only. Are you able to post a screenshot, or share the file with the rest of us?

Good job!

This was at least a good yr ago plus when Mike kirby and i talked about that head so I honestly do not remember much about it sorry. But I can honestly tell you one thing from all the heads i have cut up and the Core shift i have seen on so many ,It's not the hard to hit water if your not careful. I had a head that was done buy a shop,
WAY back when.It had 1.8 Valves in it I debated for about 3mos to go ahead and step it up to the 1.94s And not knowning How much the Other guys took out of the ports back then Turned out TO BITE
Me in the end. I desided to go ahead and Get the
1.94s put in , Once i go tit back I KNEW i was going to be in trouble Because I could see The shift in the Valve pocket area.From One to the other BIG time. So knowing already It was to late
I figured what the Heck. I went and Put lay out die in the Ports Grabed a 120 grit roll and I no sooner touch the Port JUST Barely removing the Lay
out die I could see a PIN hole and Boy You talk about feeling sick. When all along my GUT was telling me NOT to step it up. But to say the very
Least You know where that head ended Up YEP in my
CUT-up learn me PILE.
SO one of the Biggest things I learned from that
is Never go against your gut feeling OR someone
else work. This is also why Mike Kirby will not
do a Brazin on any head that has already been Ported.Because you just never know How Much someone has already cut out of it.I went against
this rule one time There after On a Clifford head and I was NEVER so nerves in my life ,trying to clean up a Jack hammered Port to install a set of Lumps.All went fine But Never again will I touch
a head that has been Jack Hammer Ported again.
Even The seats In that head were On Tilt. And Before I touched that Head I sent the Guy who Owned it Photos of it Because He had NO clue,
but we/HE!! got lucky and it ws fixable.

... by the way, I have witnessed fuel distribution problems about every time I've watched a bi-turbo 250" churning 1000+ hp on chassis dyno, fed by an alcoholic huge Holley (w/ Siamesed head). It's eye catching since the thin wall headers glow unevenly, varying according to load and speed. That’s another reason I much prefer EFI… or at least 3 pairs of Webers.

Roc, Alas, I am not insane.
Do they just run it super rich or what do you think? Can you talk to someone in Brazil?

P.S. I talked to you sometime ago about the 12 port Opala head, I got one from GM.

Thanks Harry

According to Douglas, the 12 port heads are thin & crack @ the 500 or so Hp level.

MBHD

I had my car on a chassi dyno so I know Im not pushing the 500hp. But i have had this motor Buzzing 8000 many times with my 3x4 and I never felt any issues. So is this a HP issue Or rpms??
Dang you guys dropped in a lot of posts while i was typing mine LOL
Hey does that Odd ball timing cam cost a arm and a Leg?? Or who has some kinda spects on something like that?

Larry, I think it's a fuel issue since more HP requires more fuel. The siamesed port can flow lots of air, but if the fuel does not stay in perfect suspension and favors one clyinder over another you have problems. I think the pressure waves in the port from the valves opening and closing cause the fuel to fall out of suspension.
This may be why carbs do not work as well as FI.

Just my thoughts, Harry

humm well I have had any problems with my carbs. well not as of yet anyway. But also my carbs sit right over the Intake Port/Runners. Out of all the Intakes I have ran on this same Motor/combo
My 3x4 seem to have ran the best over the others.

Harry when you say you have the dies for the U bends is that for That Intake that was on that
230/460hp motor?

Larry, Hedricks motor was a 292/550HP. The intake was for this motor it replaced a weber setup.

My current motor also has a carb over each port, when it's undivided cylinders 1 & 6 run very lean.

Hummm I guess I'll have to keep a closer eye on things with this new combo to see what happens.
esp because of this Bigger bump stick, being just shy of .700 lift.

I think having pressurized air/fuel has something to do with part of the problem of 1&6 going lean in his application?

MBHD

I've leaned towards a harmonic "bouncing" of the intake charge caused by our firing order. Log style manifolds would be the worst as they have a large volume. 1 & 6 are far enough apart to actually have a savaging effect on one another, just like an exhaust header. Just my 2 cents

OK silly question Then ? Why does not effect #2 & #5 the way it seems to #1 & #6 ??And it was to my understanding even if you went 1 runner for 1&2,3&4,5&6 a balance tube is needed?? Or does this just pertain to the siamesed port.And not to a true 12 port head.