All Small Six 83 large log exhaust porting

[Dr_Dan_WWW]

Should I use the exhaust port divider?
I am in middle of gasket match porting the exhaust on a 83 head. But it doesn't look like I gain much from porting the middle dual exhaust. I mean, I can port back about maybe 3/8 of an inch (??). Will the port divider make a large difference in performance? (The Handbook seems to say it does/it doesn't??) Will the divider make a difference if it isn't ported like the other four exhaust ports?

I am going to use headers.

What do I do about this center exhaust?

Pictures show only two exhaust ports ported. Notice the scribe marks on all the ports. This is my first time ever porting. I am learning on the exhaust before the bowls.
Thanks for any guidance.

 

[chad]

nota 'porter' here. Great job onda IMG_6837.JPG tho.
For me? the divider is for splittig the gases inta the tubes (headers in usa language) & supportin the gasket.
These motors? no gasket match on exhaust. Just not worth da time...

 

[clochard68]

I just bought the Clifford port divider, arrived yesterday. As I'm also going to use headers and because of the smaller inlets for cylinder 3 and 4 I decided to get the divider. I will use the Remflex 3061 gasket which is designed specifically for use of the divider. I will bond it in with Resbond 907...
I also read a lot of bad things about the divider, but without it the exhaust flow to the header must be terrible I assume. Time will tell if it was worth it...

 

[B RON CO]

Hi, when I cleaned up my head I did most of the work with the sanding rolls rather than the carbide burr. Mostly smoothing and blending. Nothing major.
I have the right angle and straight die grinders and I have more control with the straight die grinder.
I really don't think grinding out to the gasket line on the 3-4 port will be worth it.
Did you check the gasket match to the header flange? That will tell you something.
Good luck

 

[Dr_Dan_WWW]

Thanks - these are the opinions and experience I'm looking for.
B Ron... okay I'll looked at the header flange. (I have the cheap Amazon headers - the one supposedly copied off of Classic Inlines - not sure if that's true or not). I mean, the header flange has a center divider. I kinda picture in my mind the exhaust coming out of the undivided 3/4 port and "hitting" the center divider of the header flange. The exhaust hits the center divider of the gasket - AND the original exhaust manifold didn't seem too concerned about the exhaust "hitting" (being held up) by the factory manifold. Of course, this is the very thing we are trying to work around: get the thing breathing better.

B Ron Co, to reply to your grinding advice: you can see I have the HF angle grinder. Wish I had the straight. I am using both burrs and sanding spirals. Burrs scare me in the bowls. Actually doing anything in the bowls scares me. I will lightly roll the sharp lips off the valve guide castings. Then I am using those little 3M scouring bits just to try and put some shine on the casting surfaces in the quench and bowls. I feel comfortable with the burrs in the exhaust ports.

Chad and Clochard68, yep this is exactly my debate: does the divider make a diff? Maybe. The divider takes up actual space (volume) that the exhaust gases could use to escape. That's a negative. But on the positive side, the divider could help direct 3 and 4 ports more directly to the header tubes. This said, grinding and porting the twin port just doesn't seem like it's going to do much. I'm just gonna clean out the carbon with a spiral sander and call it good.

I still haven't decided about the exhaust port divider.
I sure appreciate the help. More responses welcomed.
Pictures below for reference.

 

[drag-200stang]

I would not build a hot rod small six without one...The even port sizes and the reduced heat transfer to the intake making for a denser air intake...The divider covers up the ridges and overall just reduces heat transfer to the intake...But in cold times it may hurt fuel mpg..For what I am doing the turbo heats the air to much to start with.

 

[bubba22349]

X2 drag-200stang, hit the nail on the head, I would use one as a carefully fitted center exhaust divider is a big benefit in several areas. The cost is low and only need some grinding a little at a time to get them to fit in correctly. Best of luck

 

[bmbm40]

That large log head is shaping up nicely for your hopped up 200. I think I would go for the 2v conversion at this stage of your build. More money I know but it will pay off every time you drive it-big smiles. The 83 is a hex log though right?
Got to have the Ray Bans.

 

[chad]

"F" opinion, look to facts (flow bench). Have U studied the tech archive. It hasa piece I think:

Classic Inlines

 

[drag-200stang]

Flow benches and dynos are only tools, that can be manipulated ...The only true facts are in a backed up time slip.

 

[bubba22349]

X2 yes that's the real truth!

 

[Dr_Dan_WWW]

Thanks folks.
I get it. The divider is only $25+. The heat transfer sounds valid and the "reverse" intake pressure sounds legit too. Bubba, the divider still needs to be tack welded, right? I cannot just set/jam fit it there, right? The Handbook says tack weld. I just don't have a welder. I will buy the divider and fit it.

bmbm40 - yes! it is a large hex log. I am super fortunate to have found the 83 200lm engine. I am swapping the 66 170 with the 83. I I really fully planned to do the 2V, but I am having a difficult time here in Kansas City finding a shop that is willing to do the work. They may be out there, but I haven't run across the shop yet.

Chad - I will study the achieve. Thanks.

What's a backed up time slip?

 

[chad]

Flow benches and dynos are only tools, that can be manipulated ...The only true facts are in a backed up time slip.

'S nother piecea data (which track?, what weather? elevation? etc - ad nauseam)

"...cannot just set/jam fit it there..."
correct, C tech archive (hi nickle rod, etc) above if Schjeldahl bros not detaied. Went slo here for head safety. May B $20 at a local shop?

 

[bubba22349]

Bubba, the divider still needs to be tack welded, right? I cannot just set/jam fit it there, right? The Handbook says tack weld. I just don't have a welder. I will buy the divider and fit it.

Yes that's right the port divider dose need to be fitted snugly and then prep the top edges of the head and port diveder so that it's V'ed in the area of each of the tack welds ths is a good way to secure it unless there happen's to be a place near you that dose the "Furnace Braising" witch is the very best way to do cast iron. Many people have installed them but there are some that were not as careful about how they fitted them and also didn't tack weld the either. Of course than when the engine gets warmed up good they are even looser enough as to start rattling that becomes annoying to them and they pull them out. This has caused some confusion and even given the exhaust port divider a bad name. In the warmer weather I have had very good luck arc welding cast iron with a nickel rod since in the hot weather the part doesn't cool down to fast. This is the real secret to welding cast iron the part needs to be warm before welding and then you need to keep the part warm and let it cool down very slowly. As for the 2V log intake mod this could be down the same way by some careful fitting and a little welding to fill in the low spots some have even done this mod themselves all with a few simple hand tools. Best of luck

 

[drag-200stang]

A '''backed up time slip'' in the the context that I meant it is ...More than one slip close in times as the other and backed with common sense. Timing systems can have glitches, a bag can blow across the beams and trip the timer early, you can put sooty exhaust under the car and get a rear wheel start, getting a head start.

 

[Dr_Dan_WWW]

Ah, I see. Nothing's perfect.
Bubba, Chad, I will check around for a someone to tack it in with the nickel 99 rod, and cool it down slow. I will get it prepped best I can. I assume the 3/4 port should be super clean and smoothed but not changed much, unless the divider needs some metal removed. I'll figure it out. Looking up Resbond 907.

BTW, the short block is at the machine shop being honed/bored, decked; new pistons, weight balanced connecting rod, journals, balance, polish crank, etc. I hope the block turns out real good. He doesn't do assembly. So I am trying to convince him to just install the pistons and crank.

 

[Dr_Dan_WWW]

Another thing. My machinist said engines sorta sag over time. That's why the cylinders get elongated. The whole block just slumps. News to me.

 

[chad]

yeah, melts like wax
8- )
just not so fast ('n dramatic).

 

[bmbm40]

One member on here fitted a Carter BBD 2 barrel carb to the stock carb riser with some mods to the carb opening and reported good performance boost. I believe he used the Carter from a Chrysler 318 application. The throttle linkage took some work also. The Carter BBD is available in two sizes, the large base and the small base for the 318. If I can find that post I will put up the link.

 

[Dr_Dan_WWW]

Thx bmbm40. I'd like to read about that carb choice.

I ordered the divider from VI. On my way!
I had the valve job done already at Noland's Cylinder Head in KCMO. Hands down they are the best in town. But Tom Noland doesn't do custom work. It's just not worth it to him anymore he says. He milled it .010 just to clean it up. New valves, guides, seals, hardened seats, and magnafluxed. Top notch work. I sure don't want to goof it up. But I will end up taking it back for milling off .035 so I can hit my target of 9.2:1 CR. Bubba's been guiding me. I wouldn't be doing this without his help and his "Good luck."

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