I would go to at least half of your cubic inces of the engine for the plenum and make sure there is no V in the bottom below the level of the intake runners because fuel will puddle there at idle and flood out the engine when you hit the trottle on take off. Lengthing the runners is a good idea, I asked a guy who builds sheetmetal intakes and he said 13 inches from bottom of valve to bottom of carb is good for 4500 to 6500. Make it longer and the power comes in at lower rpm. My intake is built on that principle and it is like you hit the nitrous button at 3500 rpm.
what OLD JIMMY SIX said and on the intakes I built they had 1/2" radius entry.length is measured from the valve which includes the port in the head
Bob, Thanks for posting the intake picture. (Old Jimmy Six) had passed that same information on to me a few weeks ago. I can see from your photo that the changes you are talking about would really improve your overall intake system. The headers look real nice and should make a big difference in performance. You may have to add a third carb to the setup. Looks like 12.50's in the future.
I've been digesting all the intake information provided by you experienced racer/builders and comparing it to what I have now. Still weighing some alternatives. I took the intake/exhaust contraption to Jerry the Sandblaster today so it will be clean & easy to modify. Also cut these power rings out of 3/8" flat stock with hole saws. How they fit the program will be shown later. But the most important thing I did today was vote for Toymaker's Evil Twin.
Got the doors back today for my '40 Plymouth Pickup which will be used to tow the dragster. That's real paint applied by a real sign painter.
Bob,, I love your header concept.. I bet that will make that slant sound pretty darn cool..Never did like the straight pipe look. Pipes need kinks in them..LOL..
Bob the doors look great, can't weight to see them on the truck. I agree with Tom on the sponsor. Old local gas station or local speed shop, maybe on some half high wood bed side boards. Looking forward to were you are going with the intake modifications. You may need to run three 2bl carbs to keep up with the intake & exhaust changes. This spring will be fun going to race or T&T with the truck/trailer/race car. Will get some good thumbs up on the freeway.
O/T, I know. Didn't want you all to think I have been slacking. Just finished all the welding on the chassis for my street/drag/autocross Fiat. 187 pieces welded together. Some are even in the correct location. Yes, sure would be nice to have a real sponsor or two. They wouldn't get much for their money though. I've offered free space on my dragster and got turned down! Yes, those senile old men do nice work. This senile old man working alone can't compete. Hope to see that car in person some day.
Hey Bob, had the pleasure of meeting those guys in person last August, there car is a true work of art, everywhere you look there is true talent showing through. I guess that comes from their shared lifetime of expeience. Nigel.
hey bob one guy working by himself doing all that cutting fitting and welding has got to be perrty slick. looks perrty slick to me . haveyou ever set down and figured out how many lineal feet of welding that is ,probly scare you to death looks good bud
I cut those 3/8" thick rings, shown above, in half and welded them to the intake runners at the plenum wall.
Doing that provided enough "meat" so I can radius the inlet from the plenum to the runner. Should give the air/fuel mixture a smoother path to the engine. Experts, is that enough radius on the left port? Mudflap261, Got at least one spool of MIG wire in the Fiat project.
Now we see what those rings were cut for. Nice idea and the radius looks real clean. Not being a builder I would have no idea if the radius is correct, but it would be fine if I was doing it. Bob is the air box around half the cu in size of the motor or will you have to add a spacer to the top rail? Really looking forward to seeing the truck/trailer/race car hooked up. I know that is something you will be proud to be cruising down the road.
You're right Tom, I need a spacer. Only about 1/4" to achieve the correct volume. Might go a little thicker if it won't hurt. Been watching Eagle Field races thanks to your kindness, sending the DVD for free. Thankyou. Lots of great HA/GR runs on there. A good motivator. Yeah, I'm pretty stoked about having the truck, trailer & dragster together. Only problem is the owner/driver is about 5 decades too old.
Bob, I think this is one of those places were "bigger" is not "better", but I am not sure. Glad you like the vidio, pass it around to some of your street rod friends. At our age we are just glad to be up and moving each day, someone's got to keep cars of the "past" in the forefront of the sport.
Bob, you can use epoxy or that old favorite JB Weld to create a smooth transition from the floor to the ports. Your idea is great to give you some meat to work with.
looking good you could epoxy a piece of hard wood in the vee for a smoother transition and not have low spots between the runners where fuel can puddle. i use dupont epoxy it's two parts mix like JB weld but comes in bigger containers. i would have never though of doing it your way, good thinking
Got the port blending finished in the plemum. Filled the "V" portion of the plemum with epoxy which should eliminate fuel pooling and provide a better path to the intake tubes for the air/fuel mixture. Made half inch thick spacer rails out of aluminum to increase plenum volume to half the engine displacement.
The header is painted silver but looks grey. Will try a different brand of paint tomorrow. Picked up some 2 1/2" tube today to make collector extensions.
Looking real nice Bob. Your intake and exhaust modifications are turning out great. Thanks for the pictures to help builders like myself see a few ways to make these changes. Sure you want to stay with two carbs? Maybe 3 or 4.
Added extensions to the collectors for a total length of 18". Everything is complete on the intake/exhaust except for putting kits in the 2 Carter BBD 2 barrels. I think 2 carbs is sufficient as my engne is quite mild and Mopar 318 V8's use one of these carbs. Three carbs would be nice for fuel distribution but I'm assuming much harder to syncronize. I neglected to thank everyone that offered guidance in redesigning and building the intake/exhaust. Only shortcoming is the intake runners are about an inch short of the suggested length. Now, on to the (automatic) transmission. More help requested...do I need a manual valve body or just a shift kit? How much stall in the converter? Is it ok to simply wire the kickdown lever full open?
Don't worry about synchronizing the carbs...Just set the linkage so they are all at the stops together, they're going to be wide open most of the time.
Bob, you are like the rest of use drag racers. You always need to go quicker and faster. The modifications should make a big improvement to performance Will we see some mid 12's this summer. Keep up the great work and remember "lots of pictures" always.
Been kinda slow on the HA/GR forum so I thought I'd throw an "art shot" out there. I discovered my camera has a Black & White mode. Tried to make this disassembly pic look like it was happening in the mid-50's. Old Jimmy Six, the only way I'll come off the line sideways is if I line up sideways. My goal is to be faster than my tow vehicle! 64Dodge440, You're right, it will be either fast idle or full throttle. Not too much syncronizing to worry about.
Since I started revamping the dragster early this winter it seems that all I do is add more weight. Weight reduction was one of the goals and I'm going backward. Changing from individual pipes to headers & adding collectors. Cutting down the seat caused me to add a crossmember for attachment of the seat back. That change forced the relocation of the battery down and rearward. It now is partially off the back of the chassis so I added a "push bar" to protect it a bit. I've heard that "ventillating" the frame, front axle and wishbones only cuts a pound or two. Do any of you run one of those small light weight batteries? With no alternator I'm kinda skeptical one would stay strong for a whole day of racing.
The Jalopy Journal
