Robert Maw?
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| Modified head for better intake geometry https://slantsix.org/forum/viewtopic.php?t=65303 |
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| Author: | Rob Simmons [ Tue Sep 08, 2020 6:18 pm ] |
| Post subject: | Modified head for better intake geometry |
There was an article in an early SSRN about someone modifying a Slant 6 head by re-working the intake runner to come in at a much higher angle. Basically eliminating the sharp curve and creating almost a Ram Air effect. The article didn’t give many details. Is anyone familiar with those efforts from so long ago? I have a local machine shop owner that is interested in playing with a Slant head in such a manner... |
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| Author: | Greg Ondayko [ Tue Sep 08, 2020 8:17 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
Robert Maw?
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| Author: | Greg Ondayko [ Tue Sep 08, 2020 8:18 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
I bet Seymour can give some specifics as he probably wrote it up. You don't mean angle milling the head do you? Greg |
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| Author: | slantzilla [ Tue Sep 08, 2020 8:50 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
IIRC, they milled round holes on an angle and epoxied in round tubes. Pretty sure they ran injectors on it. I don't think they could keep the tubes sealed and ran water into the motor. |
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| Author: | Rick Covalt [ Wed Sep 09, 2020 3:37 am ] |
| Post subject: | Re: Modified head for better intake geometry |
There was a guy with a Cricket station wagon in the 70's who had the head drilled for the round tubes and had them furnace brazed in place. Then he ran 3, 2 barrels that were 1/2 of some Holley 4 barrel. Sorry can't recall his name for sure. I do have the magazine ( not in the Slant 6 news) if you need me to look for it. The name Bob Reed seems to come to mind?? Correct name- Jim Witt, December 74 CARS Magazine |
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| Author: | Rob Simmons [ Wed Sep 09, 2020 6:02 am ] |
| Post subject: | Re: Modified head for better intake geometry |
Thanks guys. That gives me a little more to go by. Seymour said he’d show me the article and photos of the Jim Witt head once I win two rounds at the same event in the Challenger... I asked him if re-setting the 7.35 A/Alcohol record the car owns would suffice...  So Dennis... When I checked out the thread on FABO that has that article... I see that you are banned from FABO... at least that’s what your little title under Slantzilla says from those posts in 2009.... S’up wid dat...? ‘Course, the feller that posted the article “1wild&crazyguy” was banned too, so there’s that... The photos are not great, but here’s the text of the article: cars magazine writes.. ''What's so hot about the slant 6? Until last year, for instance, it powered a lil Anglia pannel truck and ran in E/altered, gernerally well under the record. Now, in the Criket it's running in L/Gas, still well under the record. Since L/ Gas has a 10-pound-per-cube weight break, a couple of hundred pounds was added to the Criket, all of it in the right place-over the rear wheels.'' Probably the most striking single improvement and modification on the engine would be the cylinder head. the slant 6 starts out with a long ram manifold but Jim Witt definitely does it one better by transforming the cylinder head into a full independent runner head and manifold. For a good start, the intake passages were milled out to achieve a more straight line approach to the port/'valve' , cutting right through the water jacket and part of the valve cover rail. Tubes made up of 18 gauge exhaust pipe were form a snug fit at the head and extend well past the orig intake flange to create a new int flange. A transition manifold, in turn, provides the change in spacing from cylinder head ports to carburetor mounting flanges and also allows the carburetor to sit vertically. Tying the tubing and the cylinder head was something of a space work project. Both the head and the tube were copper plated prior to their being furnaced brazed in a neutral atmosphere . Vac-Hyd in detroit gets gets credit for this elaborate brazing procedure.'' ''Jim Watt built his own flow bench and did an extensive amount of flow work to get the most out of this head. Part of the hump in the intake port was cut away to help the flow re-attach , and the back wall was carved out out on the intake side. The exhaust ports were enlarged and smoothed out. Also the exhaust valve guide projection and part of the hump and floor in the exh port were cut back. Jim Witt & Bob Brown section a few heads to find where they could and couldn't go. The hump area [SHORT TURN] in the intake port is too critical to blindly grind on so don't.The stock 1.60 valves were swapped for 1.72's and the 1.36's were swapped to 1.50.The change was accomplished by use of early '61 corvette F.I valves w/ 11/32 stems.'' ''During flow work Jim found that using the head of a pencil to create a disturbance at the valve seat near the valve head increased flow. This led him to try valve with a thick margin=,ore material between the seat and the head of the valve. This is easily done by cutting down a larger valve '' . ''The cam is a 'chrysler express' .675 lift solid, General Kenetics aluminum retainers, spring diameter increased to 1 9/16, Stock rockers that are plenty strong [folded steel] 'but with lock nuts' Carbs are nascar 4500 1 11/16 straight bore from venturi down, each venturi feeds one cylinder, no balance pipe.=63 main jets & use of stacks to keep fog captured fog=reversed pulse coming back to the carburetor, common with IR setups, you can use this if you keep it captured by say a stack on top like Jim Witt did. The intake pipes are 13.5 inches from the top of the venturi to the top of the intake valve=perfect I.R length. compression is 12.5 w/ 30cc chambers, 7'' rod was used with a 4.12 stroke bored+.100 over=238. they used a mopar slant windage tray by means of 340 main cap bolts. They changed dampeners and crank assembly's often do to torsional vibrations=torsioning. aluminum oils pump would explode at the bearing so TRW cast iron or melling unit is used. super T-10 trans and 6.17 gears are used'' |
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| Author: | Dart270 [ Wed Sep 09, 2020 8:03 am ] |
| Post subject: | Re: Modified head for better intake geometry |
Thanks much for the text. Very interesting. What did he run and what did the car weigh (or what is class wt)? Lou |
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| Author: | Rick Covalt [ Wed Sep 09, 2020 9:07 am ] |
| Post subject: | Re: Modified head for better intake geometry |
Jim Witt! That is it. It ran a 4 speed I know, and 6.17 gears. Must have been an 1/8 mile car?? Not sure the article has the ET on it?? I wish the article had color photos so you could see it better. That head would be nice to have to look at. Wonder what ever happened to it? |
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| Author: | slantzilla [ Wed Sep 09, 2020 10:47 am ] |
| Post subject: | Re: Modified head for better intake geometry |
I am not sure why, but I am banned for life from FABO. I have not lost one second of sleep over it.
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| Author: | Doctor Dodge [ Wed Sep 09, 2020 1:06 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
What's FABO???   DD |
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| Author: | Greg Ondayko [ Wed Sep 09, 2020 1:31 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
They are skeeeeered of the 'zilla. Greg |
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| Author: | Badvert65 [ Wed Sep 09, 2020 2:00 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
I have just these two pics in my files. Attachment: Deep Six Head-w.JPG [ 28.64 KiB | Viewed 4083 times ] Attachment: Deep Six-w.JPG [ 27.93 KiB | Viewed 4083 times ] |
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| Author: | Dart270 [ Wed Sep 09, 2020 2:05 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
Pretty cool. However, without a time and a weight, it is hard to be too impressed. Lou |
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| Author: | Rick Covalt [ Wed Sep 09, 2020 2:35 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
Quote: However, without a time and a weight, it is hard to be too impressed.
I bet Seymour knows  Article says they ran well under the L/Gas record. Now who knows what that record was in 1974? |
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| Author: | slantzilla [ Wed Sep 09, 2020 3:35 pm ] |
| Post subject: | Re: Modified head for better intake geometry |
L could have been anywhere from 11s to 14s. 
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