Did a healthy pump gas 408,a few years back. Dropped the divider plate,to make it help airflow(1" spacer as well). What are your experiences?(if you care to discuss...). Thanks
Intake plenum divider modifications.....
- Thread starter Abodybomber
- Start date
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I think we're going to try a 1' spacer when we get to the dyno stage of my engine build to see if it helps anywhere. That's still a few months off though.
No picture available from the phone, but I did the MoPar engines book mod on my LD340 set up for a TQ. The engine was at the time still on the mello side. Small cam etc...
The first thing I notes was a slight loss of bottom end but a worthy top end power increase with a higher RPM ceiling. The lack of a plenum divider shortens the runners changing the intakes chraricteristics (sp?) a little bit.
For your particular intake I myself would have tried a spacer with that mod after trying the spacer itself as OOTB. Another area to look at is the entrance from the plenum into the runner at the roof.
Let us know how that works out.
The first thing I notes was a slight loss of bottom end but a worthy top end power increase with a higher RPM ceiling. The lack of a plenum divider shortens the runners changing the intakes chraricteristics (sp?) a little bit.
For your particular intake I myself would have tried a spacer with that mod after trying the spacer itself as OOTB. Another area to look at is the entrance from the plenum into the runner at the roof.
Let us know how that works out.
I have always been skeered. I just leave them alone. I've seen too many butcher jobs in the past. But Tim, yours looks pretty good.
While we're on this subject, I'll add this. A lot of the earlier intakes you see such as the LD340 have a notch cut out of the divider in the rear. A lot of people think they know why that's there, but I do know why. Do you?
I will tell you. Those notches are not there for some kinda strange alien kinda siphoning effect. It's there for one very physical purpose and one only.
Those intakes were all made in the era when the Holley three barrel carburetor was popular. The secondary barrel on the three barrel could not open without that notch being cut out. That's the one and only reason you see it. There is no other purpose for it.
I don't know. I am just really particular about stuff I guess. I would rather run it unmodified, than risk boogering it up. Cause I aint talented worth a snot with a grinder. lol
If I do anything, I will run a spacer. Foolproof for the fool. lol
While we're on this subject, I'll add this. A lot of the earlier intakes you see such as the LD340 have a notch cut out of the divider in the rear. A lot of people think they know why that's there, but I do know why. Do you?
I will tell you. Those notches are not there for some kinda strange alien kinda siphoning effect. It's there for one very physical purpose and one only.
Those intakes were all made in the era when the Holley three barrel carburetor was popular. The secondary barrel on the three barrel could not open without that notch being cut out. That's the one and only reason you see it. There is no other purpose for it.
I don't know. I am just really particular about stuff I guess. I would rather run it unmodified, than risk boogering it up. Cause I aint talented worth a snot with a grinder. lol
If I do anything, I will run a spacer. Foolproof for the fool. lol
Is love to get my hands on a 3 bbl. Carter. I might have to make one myself since there really expensive and rare.
I had one years ago, but it was so rusted up I could not do anything with it. I got it apart, but the body ad corroded so badly, that it fell apart in several places. I have not seen another one and have ad some idiot sticks argue with me that they were ever made, but they certainly were.
I will tell you.....and I have thought of this for some time. I want to make a three barrel from a Thermoquad. I have enough of them to give it a whirl. I wonder how much more flow it would add by opening the center divider up on the secondary side. Something to ponder. I may try it.
I will tell you.....and I have thought of this for some time. I want to make a three barrel from a Thermoquad. I have enough of them to give it a whirl. I wonder how much more flow it would add by opening the center divider up on the secondary side. Something to ponder. I may try it.
You go spend the money, we'll tinker around with the old stuff we find for cheap.
Bobby, the hardest part to doing the TQ as you thought of is sealing up the phenolic resin as so not to leak gasoline. Making a big single throttle blade is the easy part.
I'm in the middle of doing a AFB double pumper. I await warmer weather to finish. From there, it's on to finish the Edelbrock 600 into a 3bbl. I have yet to combine the two works into one 3bbl. DP carb. I don't think it will be to hard to do myself. I just need time to tinker on it.
IMO, yes, it would.
daliant
Befuddled
What was the reasoning behind the 3 barrel carb? was it just a gimmick or did it have a performance gain over an equivalent sized 4 barrel carb?
Rob,I would so love to see that one done.
They were original equipment on several "specialty" cars, such as the Baldwin Motion Camaro, Some of the Yenkos cars and they were also used by NASCAR. There were two sizes from Holley. The 950 and the 1050. Both were vacuum secondary carbs, although there was a kit consisting of two half moon gears that attached to the throttle shafts that made them not only mechanical, but 1:1 in regards to the opening ratio of the primary and secondary barrels. There was also an extension with the kit for the primary pump squirter that transferred fuel to the secondary barrel as well.
The idea was to do away with the "dead space" between the secondaries to allow for more flow while still retaining the 4150/4160 base plate. This allowed the cars to run in classes they normally could not if they had a dominator. The carburetors worked incredibly well. I am gonna find out when I get my 383 together because I have a 950 rebuilt and ready to go.
daliant
Befuddled
Yeah I kinda figure it had something to do with skirting the rules of having to run a certain sized carb. Thanks for the info.
fishy68
Tyr Fryr's Inc.
I thought about doing that exact mod to my Air-gap but asked opinions from 2 top engine builders first and they said just use a 1" spacer, that there wasn't anything to gain cutting the divider back so I took their advice. Found the 1" spacer really woke up my 408, like night and day. By your description it sounds like you've already ran this intake? If so did you do a before and after comparison?
Basically the same as the 1" spacer ,Fishy.
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