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4bbl on Slant
https://slantsix.org/forum/viewtopic.php?t=35138		 Page 1 of 2
Author:  81dodged150 [ Fri May 01, 2009 10:41 am ]
Post subject:  4bbl on Slant
I was seriously thinking bout putting a Holley 380 or 450 (I think thats the size) on my 81 Dodge truck. I guess what im asking is how hard to get this operation to work properly? Ive heard that a 4bbl was alittle to much for a slant and thats why im asking. Also would a have to change the cam and/or have the head redone or anything else for that matter. Also bout how much would this all cost me and what am i looking at for h.p. and torque and for drivability issues. This will be a daily driver. Thanx in advance :)
Author:  66aCUDA [ Sat May 02, 2009 7:21 am ]
Post subject: 
Joe
Is your truck still a LEAN BURN? If so I know what you mean about a gutless pig. You need to ditch the lean burn system. There are several discussions going on right now about the conversion. I did this to my 87 and its Great.
As for your question about a 4bbl. My IMO you need to do a pretty good amout of work to the head and change cam at the very least. A machine shop will charge you about 1K to do all the work. This does not include the cam or carb either.
Frank
Author:  DARKDUSTER [ Sat May 02, 2009 8:09 am ]
Post subject: 
Joe, I installed a Holley 390 4BBL on my '70 Duster with Clifford heated intake & shorty headers. This engine has the mildest cam they ever put in a 225, [232 adv. duration]. The toughest part was to get the idle speed down and still run high initial advance. I believe the key is heated intake manifold [with coolant], not a huge gain in performance but it runs well.
The Holley was right out of the box from Summit Racing and comes with a great DVD on tuning. I am currently preparing a head and specing out a cam to multiply my gain..... Hope this helps.

DARK
Author:  SlantSixDan [ Sat May 02, 2009 9:09 am ]
Post subject: 
Quote:
This engine has the mildest cam they ever put in a 225, [232 adv. duration].
Someone swapped a pre-1965 camshaft into your '70?
Author:  Chuck [ Sat May 02, 2009 2:27 pm ]
Post subject: 
I had a 390 on my Dart for a while but never got the power valve to work correctly. There was always a hesitation when accelerating. A friend installed one on his Dart but also installed Weber adapter plates on it for better tuning. I don't remember what those Weber pieces were called, but they helped a lot. I actually preferred the 2 bbl installation, which I think is about 280 cfm. I had a custom Crane cam installed:

Image
Author:  DARKDUSTER [ Sun May 03, 2009 6:57 am ]
Post subject: 
Quote:
Quote:
This engine has the mildest cam they ever put in a 225, [232 adv. duration].
Someone swapped a pre-1965 camshaft into your '70?
No cam change, the car has been under my watchful eye since new. I'm just going from info found that Mopar had a brain fart in '70 and put that weak cam in, then from '71-'80 went to the marine 244 adv. dur.[something like when they lost the fact that slants like RDP cams] Until the fine fellows @ Slantsix.org brought it back..... thanks guys!!!!!

DARK :D
Author:  SlantSixDan [ Sun May 03, 2009 9:22 am ]
Post subject: 
225 from '60-'64 and 170 from '60-'65 had a cam with specs 232° intake duration, 228° exhaust duration, 0.37x" lift, and 8° overlap.

225-1bbl from '64-'70 and 170 from '66-'69 (+'70 export) and 198 in '70 had a cam with specs 241° intake duration, 236° exhaust duration, 0.39x" lift, and 16° overlap.

225-2bbl (export only) from '67 on and 225 (domestic) from '71-'80 and 198 from '71-'74 had a cam with specs 244° intake and exhaust duration, 0.420"/0.414" lift, and 26° overlap.
Author:  DARKDUSTER [ Mon May 04, 2009 6:22 am ]
Post subject: 
Thanks Dan for getting me straightened out on my factory cam.... that makes more sense. I rechecked my sources and it wasn't slantsix.org, plus I did some assuming :oops: So that 241 adv.dur. would still be rather mild Joe and it works for me.

DARK :)
Author:  rock [ Mon May 04, 2009 9:49 am ]
Post subject:  Joe, is your quest. really about the 81, or about the use of
Joe,

Are you asking about the change on an '81 specifically, or about the use of the 4bbl, in general? I ask cause one answer you got is for a '70, then Frank's is asking you about lean burn.

I am one of many guys here who have tried several 4bbls on the bare engines like the '60's and the 4bbl is great after some engine building. Not hard to do at all, from my point of view. You can find a thread where I compare and contrast the classic Eddy 500cfm to the Holley 390cfm. I wouldn't even attempt it until you have a well ported head so it can breathe in and a good exhaust system so it empty, and enough compression via milling to make the power potential wake up, and bigger valves to help it all work. And a good ignition system like MSD or the GM HEI. I built mine for low end torque and it is perfect after a bunch of recurving aided by a wideband sensor. If you don't really want to spend a couple thousand for head, carb, manifolds and the rest then best stick to a 2bbl, but the 2bbl will also benefit from good head work.

rock
'64d100
Author:  81dodged150 [ Mon May 04, 2009 11:16 am ]
Post subject: 
I took all that Lean Burn Sh!t off because given it is a marvel but it is a stupid thing. And i guess exactly what would i have to do to my head to have it accept a 4bbl. I know i have to put a better exhaust system on such as headers but now im running into that whole thing of weather i should just yank it in favor of a 360. I originally wanted to keep the slant in there and do a few mods to it but im not going 2 spend that much money on the slant if i can stick it into a V8 and get twice the amount of h.p. and torque. So i guess to put it bluntly should i just put a super six on it? This motor is just not performing up to par which is why i need something to boost the power a bit.
Author:  vynn3 [ Mon May 04, 2009 11:34 am ]
Post subject: 
If you're wondering whether or not to swap in a V-8, then you probably should.

vm
Author:  Aggressive Ted [ Mon May 04, 2009 2:53 pm ]
Post subject: 
How much HP and torque do you need? A SL6 can put out as much as a stock 318 with a few mods.
Author:  81dodged150 [ Tue May 05, 2009 8:49 am ]
Post subject: 
Well thanks guys for all ur expertise in helping decide whats better.
Author:  66aCUDA [ Wed May 06, 2009 6:21 am ]
Post subject: 
Joe
Did you put a new dizzy on after you got rid of the Lean Burn? If not that is your problem. You wont have any vacumn advance with a lean burn dizzy.
As for the V8 its up to you. There is alot of things you must swap to get a V8 drive train in place. I believe its easier and cheaper to keep the slant.
JMHO
Frank :D :D
Author:  81dodged150 [ Wed May 06, 2009 7:37 am ]
Post subject: 
66aCUDA,
R u talking about the distributor cuz that was changed also. Came outa a 80 Volarie wagon. Not the same advance curves but im not too worried i think. Also i do have an oil pan, linkage, mounts and driveshaft for a V8 in a pickup. But thanks for the help i think ive made up my mind on what ill do :D
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