extrude honing intake

Fathead Racing

Well Known Member
Supporting Member 7
Fathead Racing. Thanks for the reply, yes these old posts are full of great information from experienced people. I'm actually using a 2" spacer under each carb. They are 2 barrels instead of an open plenum. I can cut out the divider and open them up to one big oval hole if you think that might help or accomplish the same goal. Just a thought
I want you to do a little at a time and look for gains. It's hard to turn things around after you cut. The more you open the mounting pad and the plenum area the less carb signal you'll get. You may get past the sweet spot and end up with a turd at idle and drivability problems.
 

Aducati4me

Well Known Member
Hey fathead racing thanks. I might have the manifold ported professionally and leave the dividers alone. Here’s what I’m thinking, the spacers are 2 round barrels 2” tall. The adapter to go from large base to small base 2g’s is 1” thick and is open plenum so both barrels will be mixed before it gets to each separate barrel of the spacer. If I’m following you correctly, that’s the goal. Use both barrels of the carbs instead of one per side. I just want to open up the bottom edge of each long port as there is about a 1/2” that could come out in an arc to help direct the flow instead of a 90* angle. (Probably the most inefficient part of the whole thing) And port match the intake to my heads. Does this sound logical or am I on the wrong page?
Sorry to be a pain but I’m learning here. Lol, at 61 who says I still can’t learn. Old dog, new tricks.

I tried to upload some pics but wrong type file. The spacers and adapters are from Dashman.com.
I need to get the carbs up high enough to get the Hilborn scoop up high enough to integrate into the hood hole/scoop of a 56 GMC. That’s my thought anyway.
 

Fathead Racing

Well Known Member
Supporting Member 7
Hey fathead racing thanks. I might have the manifold ported professionally and leave the dividers alone. Here’s what I’m thinking, the spacers are 2 round barrels 2” tall. The adapter to go from large base to small base 2g’s is 1” thick and is open plenum so both barrels will be mixed before it gets to each separate barrel of the spacer. If I’m following you correctly, that’s the goal. Use both barrels of the carbs instead of one per side. I just want to open up the bottom edge of each long port as there is about a 1/2” that could come out in an arc to help direct the flow instead of a 90* angle. (Probably the most inefficient part of the whole thing) And port match the intake to my heads. Does this sound logical or am I on the wrong page?
Sorry to be a pain but I’m learning here. Lol, at 61 who says I still can’t learn. Old dog, new tricks.

I tried to upload some pics but wrong type file. The spacers and adapters are from Dashman.com.
I need to get the carbs up high enough to get the Hilborn scoop up high enough to integrate into the hood hole/scoop of a 56 GMC. That’s my thought anyway.
Be careful when your messing with port shape. There's a lot more to it than just grinding away material. If you hog the port out to much the air fuel mix will slow down. If it slows to much the fuel will fall out of suspension and you would get puddling. Anytime you have a wet manifold you shoot for what is referred to as a pebble finish like a golf ball. This helps to keep the fuel in suspension. Do not polish the runners.
 

Greg Reimer

Well Known Member
Did you ever see the port arrangement and spacing between a Mopar wedge,either a B engine or an RB motor intake ports and a 409? Take a 409 intake gasket and lay it on a Mopar intake flange. The port matchup is incredible. This being the case, the 440 Six Pak intake would be a real possibility if you wanted to machine the thing down in the proper places to make it work. There was a guy when I first started doing the 409 thing in the late '70s that flycut a 409 881 intake that was damaged, he left the intake flanges, the front area where the water crossover and the thermostat area is, and the corresponding rear area including the distributor mounting area. In short, he took a 409 intake and milled off the plenum. He then took a wedge motor tunnel ram and trimmed the intake flange areas off until he could mate it to the 409 intake. It was an ambitious project, but it would widen the choices of available manifold combinations and configurations for the 409. Think of the Tri-Power intake the 6 pack combination would be!!!
 

Greg Reimer

Well Known Member
Seems to me that Edelbrock cast a lot of Six Pack manifolds for 440's in aluminum. That would be easier to work with when putting together a 409 aluminum intake. The tunnel ram was a bit temperamental to tune and work with, might yield a better return on your investment of time,effort,and materials to start with something else.
 

Aducati4me

Well Known Member
Greg Reimer do you recall if the intake gasket matched up to the small port low horse motors or the 583/690 large port heads? I’m only dealing with the low hp 333/817 heads.
 

Aducati4me

Well Known Member
Probably not something I’m willing to spend a lot of time on but it sounds cool Greg. If Tripower (member) can get 460 hp from a stroked 348 using a basically stock small base tri-power manifold I think there may be untapped potential in this so called boat anchor. I have one that I’m going to let my machinist experiment with on a flow bench and see what happens. I’m sure I’m not the first to try this but they haven’t posted anything that I’ve found yet. Since I’m using such long spacers I’m not going to polish anything, like Fathead Racing said, just open up the flow path a little and radius some of the square corners. I know It will never reach the potential of a single 4, that’s not my goal. My goal is to make it run as efficiently as possible. If I decide to take this on I will keep track of the findings and post pics for sure. Depends on my machinist.
 

tenxal

Well Known Member
Worked with the Edelbrock big block Mopar intake to fit up to a 409 years ago. The B intake worked better than an RB due to the runner angle (the B being a shorter deck than the RB).

With the proliferation of single plane intakes now available it would be even easier. I used .250 thick 6061 T6 for the valley pan and intake sides. Water crossover was a AN-10 fitting on each side to a block that held the water outlet. For the distributor, a piece of .500 thick round 6061 was used for the dist. housing flange. Today, a slip collar distributor would be the way to go.

If I was going to do another one now, I'd likely opt the TFS 'B' intake as it's generous curve to the heads would open more opportunities.
https://www.trickflow.com/parts/tfs-61600111
 

Greg Reimer

Well Known Member
The intake gasket I saw being compared was the large port 409 intake being held up to the Mopar intake.The B intake might be the optimal one, did anybody make a 361-383 trip power intake? If tri power is your thing, the 440 RB intake would be the one to use.There was a 383 in line dual four barrel engine out around '63-64. There used to be a Plymouth wagon in Stock Eliminator out here that had one and it was pretty fast at the time.I'm glad to hear somebody else actually has studied this concept and has tried it. In a forum this size, it's more likely.There's two famous last words in drag racing--"That'll never work" and 'That can't be done". Saying that is like waving a red flag in front of a bull.
 

Greg Reimer

Well Known Member
Back when we had my club, a New Jersey member about 1979 or so came up with,of all things, a '61 impala 4 door sport sedan, 348,250 horse, 3 speed stick car, and he got a wild idea of trying it in NHRA Stock Eliminator with a 4 speed,4:88's, a steel spool and some good axles, either Warner Headers,or some Stahl's. He called some cam grinder to get a 348 stocker cam, back when they had a max duration spec,unlike the cams we use now that only have to check for lift,and he put some research into it. It fit NHRA O/S, 15 pounds per horsepower,at 250 rated horsepower and with 170 pounds added for the driver's weight, it wasn't exactly light. He ran a Muncie 4 speed, probably the wide ratio, and the rule book stated"Any OEM type intake",so a consultation with the Div.1 tech director verified that he could run the factory aluminum piece,even though they never came on the 250 horse engine,it was an accepted part. He had some head guy back there do up his heads, got a good 4 jet,not too hard since the 220 horse 283 and the 250 horse 327 all used the same one as the 348,and while he was getting another block assembly built, he put together what he had and it ran 13. 70 at 101 or so, with the 70,000 mile old used short block that came into the car. After the good short block came around, it ran a lot of 13.00's and even a few 12.95's. Kind of an amazing thing. The O/SA index now is about a 13.00,the stick index is probably about a 12.90. With today's stuff and improved technology in just about everything, this could go probably 12.60's. I think much technology that could have helped the small port engines in the way of heads, camshafts,and intakes especially probably went elsewhere,and we never really got to see what a 348 was capable of doing. The newer intakes spliced to a W motor base might show up some real surprises on a dyno.You never know!!
 
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