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 Post subject: Head porting
PostPosted: Sun Apr 16, 2017 2:37 pm 
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TBI Slant 6

Joined: Tue Nov 06, 2012 4:30 am
Posts: 122
Location: LEBANON, MAINE
Car Model:
I plan to gasket match ,debur intake and exhaust . Installing larger engine builder valves

I'll be running 6-9 lbs of Boost with super charger

So I am assuming I can
polish the exhaust port smooth ??
Intake is normally left semi rough to help fuel mixture is this true on forced induction ??

And the chamber on the head polished smooth or rougher as cast finish ??
Thank you all

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1963 Plymouth Valiant Wagon


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 Post subject:
PostPosted: Fri Apr 21, 2017 1:13 pm 
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TBI Slant 6

Joined: Tue Nov 06, 2012 4:30 am
Posts: 122
Location: LEBANON, MAINE
Car Model:
Pulled the valves and Ran the head thru the washer few times all clean 👍👍

I magnafluxed it all is good ready to start with port and polish
Let the fun begin !!!!

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1963 Plymouth Valiant Wagon


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 Post subject:
PostPosted: Mon Apr 24, 2017 2:03 pm 
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Turbo EFI
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Joined: Mon Jan 12, 2015 5:55 am
Posts: 1102
Location: Brightwood, VA
Car Model: 1965 Plymouth Belvedere I
Be careful removing material. Especially in the area where the two valve bowls are next to each other. Don't ask me how I know.
-Matt

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-MattMan
Strive for Excellence, not Perfection.
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 Post subject: Re: Head porting
PostPosted: Wed Oct 21, 2020 3:32 pm 
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TBI Slant 6

Joined: Tue Nov 06, 2012 4:30 am
Posts: 122
Location: LEBANON, MAINE
Car Model:
I plan to gasket match ,debur intake and exhaust . Installing larger engine builder valves

I'll be running 6-9 lbs of Boost with super charger

So I am assuming I can
polish the exhaust port smooth ??
Intake is normally left semi rough to help fuel mixture is this true on forced induction ??

And the chamber on the head polished smooth or rougher as cast finish ??
Thank you all

So after life getting in the way this project is back on does this type of porting seem right thanks

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1963 Plymouth Valiant Wagon


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 Post subject: Re: Head porting
PostPosted: Wed Oct 21, 2020 4:06 pm 
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Supercharged
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Joined: Thu Jan 27, 2005 8:32 pm
Posts: 7696
Location: SW Washington
Car Model: 1965 Plymouth Barracuda, 1954 Dodge C1-B8
I have come to believe that port matching is useless. Who says the gasket has the correct port size? Have ypu noticed the intake ports are already larger at the head face? Productive work will be within 1" of the valve seat.

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Joshua


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 Post subject: Re: Head porting
PostPosted: Wed Oct 21, 2020 4:23 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 6187
Location: So California
Car Model: 64 Plymouth Valiant
Gasket matching isn't necessary.

You just need to make sure the casting boogers are removed and things are smoothed.

Since the exhaust manifold (and possibly the intake manifold) move with heat, just make sure the airflow never hits a step.

This can be done by a slight step up in port size in the flow direction. (head port slightly bigger than intake manifold / exhaust manifold slightly bigger than head port). The small step up in size doesn't affect flow (at least at our power levels) but a step down in size would affect flow.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

8)


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 Post subject: Re: Head porting
PostPosted: Thu Oct 22, 2020 4:08 am 
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Board Sponsor & Moderator
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Joined: Mon Oct 21, 2002 11:08 am
Posts: 14659
Location: Blacksburg, VA
Car Model:
Your plan sounds good. Everyone's comments above are good ones. Most of the action is in the bowls, where you want to open to match the valve sizes. Yes, do not get happy with the section near the bowls and between each I and E port. Water lurks...

Lou

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"You mean you still have a Slant 6 in that thing?"


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 Post subject: Re: Head porting
PostPosted: Thu Oct 22, 2020 6:55 am 
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TBI Slant 6

Joined: Thu Apr 18, 2019 7:57 am
Posts: 142
Location: Lawrenceville, GA
Car Model: 1966 Dodge Dart
I ended up gasket matching both the head and the manifolds. I'm not sure if it will do very much, but it didn't add very much time to the overall port job, and revealed a pretty significant mismatch (around 2 mm) between the Clifford intake manifold and the head ports.

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Matt Cramer
1966 Dodge Dart turbo / EFI project


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 Post subject: Re: Head porting
PostPosted: Thu Oct 22, 2020 5:49 pm 
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Supercharged

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 3213
Location: Indianapolis
Car Model:
the one thing i have to offer is that I agree with Josh, the most port flow gains happen due to improvements that occur with in inches of the valve seat. Gasket matching, port arm refinements are hocus pocus at best a waste and an energy killer at worst. Find a better way if you choose to or consider what DV says on the subject.
https://www.musclecardiy.com/cylinder-h ... ds-part-8/

I am working with a valve seat guy that does porting on circle dirt track sprint car motors. Bigger motors than ours, but motors that need instant response. He thought the 30 degree seats were nuts, I am the customer so I got him to do it, time will tell. Bottom line is I don't think there are any 'slant six experts',, its more about experimenting and testing and finding the combinations that work for you.
This is not to say the slant six is totally unique in engine architecture and requirements, but to say slant six engines have their own optimization, like any other engine.


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 Post subject: Re: Head porting
PostPosted: Sat Jan 02, 2021 1:48 pm 
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TBI Slant 6

Joined: Sat Mar 19, 2016 7:25 pm
Posts: 212
Location: SW PA
Car Model:
Port matching isn't really about "gasket matching", and with the way a Slanty intake can be mis-aligned with the actual ports in the head, it pays to use the gasket as a guide to open the head to accommodate this. The port in a "peanut-plug" head is embarrassingly small, only~1.25"sq. where the guide boss & floor are closest in proximity. That will port velocity limit a 225 to 4,600rpm, period, unless You're using a roller or fast-ramp/high rocker ratio combo. As stated, the bowl & valve job along with larger valves is critical to making the oats & step #1, especially with boost. But that choke-point in the port must be corrected, & it certainly can be. There is enough meat there to take You well into the 6's. Boost can cover-up flow inefficiencies, down low & mid-range for sure, but (esp. turbos) can expose them fast at higher rpm's where the curve can fall off a cliff..............


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 Post subject: Re: Head porting
PostPosted: Sat Jan 02, 2021 2:57 pm 
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Board Sponsor & SL6 Racer

Joined: Wed Oct 23, 2002 7:57 pm
Posts: 6729
Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
[quote]with the way a Slanty intake can be mis-aligned with the actual ports in the head, it pays to use the gasket as a guide to open the head to accommodate this.[/qu

This is true! The intake and exhaust can be misaligned a great deal in my opinion. I always use the gasket to get the intake ports lined up with the head when I mount them. Also on aftermarket intakes the runners themselves can be misaligned- Up an down from each other quite a bit.

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 Post subject: Re: Head porting
PostPosted: Sat Jan 02, 2021 4:00 pm 
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TBI Slant 6

Joined: Tue Nov 06, 2012 4:30 am
Posts: 122
Location: LEBANON, MAINE
Car Model:
Santa gave me a Milwaukee 1/4 die grinder

Elf’s gave be carbide burr set and a sanding roll porting set

#1. I need to test fit windage tray and crank scraper

#2 Test fit timing tab for Romac balencer

#3. Pull pistons and mark bores on to head
Then the porting and polishing will start

_________________
1963 Plymouth Valiant Wagon


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 Post subject: Re: Head porting
PostPosted: Sat Jan 02, 2021 7:43 pm 
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Supercharged

Joined: Wed Sep 17, 2008 6:48 pm
Posts: 3213
Location: Indianapolis
Car Model:
Another place to work to add port flow is in the combustion chamber, by un shrouding the valves.
A way to do that is, with the crankcase on the rollover, prior to installing the crank, bolt the cylinder head to the block and roll it over so the pan rail is up. Reach inside each cylinder and using a very fine tip marker, trace the circle that is the interface of the combustion chamber to the cylinder wall on each cylinder.
Roll the case over and remove the head. Observe if there is material on the combustion chamber wall that can be remover to increase the gap between the intake - exhaust valve and the combustion chamber wall.
If so remove material from the combustion chamber wall out to the diameter of the cylinders. This is where when doing an overbore on the cylinders going to +.060 or more can make a difference. If you feel racey, open the chamber close to the valves to the diameter of the head gasket.
As with any combustion chamber work, keep the final volumes equal as possible. Coordinate the volume change with other deck work to achieve your targeted compression ratio.


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