1966 Monaco 4 BBl conversion ( Camshaft ?)

KJoeZ61

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I have a stock 4 door 66 Monaco that I installed a 4 BBl intake and carb on several years ago but didn't swap the camshaft. The engine runs great however its got a few oil leaks and the freeze out plugs need to be replaced so I'm pulling the motor this spring because its time to address these issues. Could anyone recommend a good camshaft & lifter kit to put in? Also planning on replacing the timing chain as well.


The cars exterior and interior were fully redone a few years ago, its a solid car and it deserves these improvements. Also it was converted to duel exhaust as well.


Joe
 
There's always the good old. 484 Purple Shaft from Mopar. I have that in my 66 Polara, 440/727 3.55 8 3/4 is nice for.a cruiser that you can have a bit of fun with
I asked Steve Dulcich what to put in and he recommended a Comp Cams 275XE for it. It's a modern grind Cam that has good street tendencies.
 
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You can throw the purple shaft in the 383, maybe not the 275XE. Maybe a step lower than the .484 would be better?
 
Since you have it apart, why not add unleaded gas exhaust valve seats? Pretty common machine shop job, should not be too pricey.
383 heads have a casting hump restriction in the exhaust passage. Removing them is worth about 15 horsepower; the improvement is detailed in the Mopar Performance engine manual.
Mark
 
Welcome.........
If it's running good, just install a double roller gear/chain set and button it up. If you do change the cam, avoid any Comp cam products, or any Chinese made products.
Also, those are not "freeze out" plugs. They are core plugs, good to use brass replacements.
 
I just installed a Comp XE262 in an otherwise stock 383 I've been rescuing for a customer. Engine now has a 6bbl and windage tray among other things. Runs great on the stand. Will be in the car this week.
I would not buy an MP cam unless you also purchase the degree setup to check it. The designs are old, but may work. The current quality is highly suspect based on my own history/experience. I like Comp product and use it a lot. I have not experienced any quality issues, unexpeted noises, or ever lost a lobe but there are some reports of manufacturing issues I've heard about.

One side note - any new cam will require new pushrods. The pre-68 big blocks all use longer pushrods with a smaller lifter-end radius than the 68 and up engines do. The aftermarket cams are all coming with the later design lifter - so you have to use the 68 and up pushrods.
 
So here's my plan. since I'm pulling the engine anyway, going to send out the heads to be gone over and redone. Then I'm going go with COMP Cams K21-215-4 which is the whole kit, just didn't realize that I need to change the push rods also. With this said I'm basically re doing the whole upper end. The engine has about 95,000 miles on it and runs good, am I opening up a can of worms for the lower end?
 
In terms of a budget build, things are easy. You avoid spending unless you have to. What you're doing, is sort of "in the middle". I will attach a summary and few pictures of that 383 I mention when I'm on a different PC as this one can't upload. It was a running engine & budget build initially. Then it sat for 10 years in a wet garage while the owner had some life-lessons occurring. It's still budget, but I'd call it a hybrid now because of what had to be done to clean up the mess. The reason I get into this is, I'm of the opinion that if it works (good enough) then leave it alone. If I inspect a 90K engine, I will find issues. The problem is "Then what?" So if it runs, it will run again. It might run a little better, for a length of time. It is unrealistic to expect a worn engine to behave like a rebuilt one. However, an in-service engine will make use of any performance enhancing or replacement-for-worn parts too.
So if it runs well now: have the heads done (wise choice and part of the regular maintenance back in the day); replace the oil pump pickup, pump, oil pump drive bushing, and drive; I'd run the MP thin head gaskets rather than the thick Felpro/others' stock replacement ones; clean the piston tops by bringing the piston to TDC, using brake clean, a brass bristle brush, and finish with a rag. Then turn the crank so the piston goes down the bore and wipe off the crap left at the top of the cylinder where the top ring stopped; bottom tap the head bolt holes; clean the gasket surfaces; and stick it back together. The "next level" would be turning the crank, running a flex hone very lightly through the bores, and new bearings, rings, and rear main seal. You will probably need a ridge reamer to do that given the mileage and it's easy to screw that up so be careful. Aside from that you're getting into full rebuild territory. Prices go up quickly at that point.
 
Another older thread . . .

Back when those motors were built, one reason they might not have put out comparable power as a Chevy was that they were "set up tight for long life". Hot Rod magazine did a build-up on a 1968 383/325 motor. In order to get the power past about 425, no matter what they did, cams, carbs or whatever, it would not make more power . . .until they pulled it apart and clearance the pistons and bearings. So, with normal/decent maintenance, they'll go well past 100K with no issues. Even past 150K.

The stock cam in those motors is the same one that first appeared in the 1958 Sport Fury 350 2-4bbl V-8. Mild by normal standards, with .390 lift and about 252 advertised duration, but it works. Be that as it may.

My experiences have been, on our Chryslers, that by about 80K miles, #7 exhaust valve had "burned" and a valve job was needed. Only did that one head and that one cylinder. So, freshening the valve job might be a decent deal, BUT the old orientation was that when you make the seal "on top" better than the seal "on the bottom", it might cause some issues with blow-by or oil consumption. But, I couldn't tell any big difference on my cars.

I would suggest either the Mopar Perf roller timing set or a Cloyes Plus Roller (I put 400+K miles on one in another motor with no issues). Add the windage tray in the crankcase, too, for good measure.

So, unless there are some noise or oil pressure issues related to crankshaft bearing wear, DON'T mess with that.

For cams, try to find one with 114 degree lobe separation, rather than the common 110 degree lobe separation. I did a 110 degree cam in another engine and I had to play with the advance curve springs to get it better than it was. Intake vacuum will be better with the 114, typically. Most stock cams are on the 114 degree situation.

For the cam "to work", you'll need dual exhausts. The HP manifolds are priced too high for what they are AND usually look like (rusty!!), keeping the stock manifolds might be the best "low cost" option, then getting some 2.25" pipe C-body normal dual mufflers and putting the exits at the rear stock location.

You WILL need the Edelbrock linkage extension item to get the 2bbl throttle linkage to work with the 4bbl carb. You'll probably need to shorten the factory part to get the adjustment right. The kickdown rod adjustment, from the factory, keeps the part-throttle upshift points too low, from my own experiences. From the factory setting (2 turns preload, per service manual instructions, go an additional 2 turns and call it good. No durability issues! It'll accelerate faster with less throttle with the slightly higher upshift speeds. It does make a good difference! With the 2.76 rear axle, it should put it into high gear at about 28mph or so, rather than sooner and making any further acceleration from that lower upshift point "on the converter". With a 3.23 rear axle and the tire size on that car (originally 8.55x14, I believe) it should be right at 25mph.

Adding an electronic ignition might be an option, for good measure. The MP kit is a good one and provides a factory distributor with a faster advance curve in the mix. Just do NOT use the supplied or recommended voltage regulator!!!! PERIOD!!! Using the recommended one kept the voltage at 14+volts all the time. The race manual also notes that it'll negatively affect ALL electrical items on the car, durability wise. I found that out! Went back to the stock unit and had NO problems. Stock or stock replacement ONLY. With the electronic conversion, about the only thing really gained is no point changes, which can be a plus.

Add some iridium spark plugs while you can do that. Set them at about .038" gap and that'll be the last ones you'll need to buy. Adding some magnetic suppression plug wires can be a plus, too.

Stay mild on the cam as the tighter torque converter and highway gears need low end torque to work best. What you'll essentially be doing is putting more rpm into the motor's capabilities without really compromising low rpm performance (which is where we normally drive anyway).

Let us know how it's progressing or has happened.

CBODY67
 
Add some iridium spark plugs while you can do that. Set them at about .038" gap and that'll be the last ones you'll need to buy...

Wich iridium spark plugs can you recommend for a mild street 383?
 
Another older thread . . .


My experiences have been, on our Chryslers, that by about 80K miles, #7 exhaust valve had "burned" and a valve job was needed. Only did that one head and that one cylinder. So, freshening the valve job might be a decent deal, BUT ....

The kickdown rod adjustment, from the factory, keeps the part-throttle upshift points too low, from my own experiences. From the factory setting (2 turns preload, per service manual instructions, go an additional 2 turns and call it good. No durability issues! It'll accelerate faster with less throttle with the slightly higher upshift speeds. It does make a good difference! With the 2.76 rear axle, it should put it into high gear at about 28mph or so, rather than sooner and making any further acceleration from that lower upshift point "on the converter". With a 3.23 rear axle and the tire size on that car (originally 8.55x14, I believe) it should be right at 25mph.
CBODY67

Thanks again for yet ANOTHER AMAZINGLY RELEVANT BIT OF DATA! Did a compression check a couple weeks ago, which gave me surprisingly good results, averaging out to ~ 142 psi because #7 read LOW at 121 psi, compared to other good reads. # 8 also came in in the 130s. Given that the factory compression is 165 psi, I was pleased w the overall state of this old motor. Seeing what I have here, I'm now contemplating a ring and valve job for the Fall.
 
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Agree!!
But still, wich iridium spark plugs can anyone recommend for a mild street 383?
 
Wich model of NGK?
I can't find any cross reference chart to translate my Champion RJ14YC to a iridium spark plug
 
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