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1966 coronet 440 383 4spd/ rebuilt is a dog need suggestions

it has small tube headers. the machine shop that assembled the motor stated 10:1 cr used the .40 replacement head gasket. i ask them to use a .20 shim if needed to get 10cr tomorrow I'll start checking cylinder psi, vacuum leaks again i know I'm just missing something silly appreciate the help

If the shop that built your engine told you 10:1, I'd ask them for the actual measurements they used to arrive at that compression ratio. They'd need to know actual measured CCs of the combustion chambers after machining the heads as well as where the pistons sat in the hole at TDC after cleaning up the block deck.

Using some of the commonly known measurements taken from these production engines; your KB400 piston specs, and the measurements of your compressed head gaskets, your engine is likely 9.0:1 as seen with this Diamond calculator pictured below.

The CompCams #287TH7 calls for 9:1 compression, but the problem I see is that Comp is making the same recommendations on the cam card for both the 383 and 440. That's a significant difference in cubic inches. That said, I still think you're over-cammed with your given combo. Instead of the 287, I'd be looking more towards a 272 or even a 268 for what would be a happier more potent 383.

But really, my next step would be to call and get some recommendations from Bob Karakashian. Bob knows these Mopars really well and can make some suggestions to you.

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Book spec on 66 383 is 10:1

Similarly, the "book spec" on my 69 383HP is 10:1, but the actual measured number is closer to 9.3:1. These assembly line production engines varied some in specs and the published numbers are a bit optimistic at best.
 
yeah i wish i would've thought the build out little better. i didn't realize 383s where so non-cookie cutter. now i need to back track. the 383 is a 66 4bbl flat top i thought using the kb400 with open chambered heads would set the cr above the 9.5:1 within cam requirements again thx for the help its like talking with a good therapist.
 
You should be able to see by looking at where the head meets the block and be able to tell if the .020" head shim was used vs the .040" regular head gasket. The thin gasket will give you about 1/2 point of compression. Closed chambered heads will give you another 1/2 point.
 
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Boy you've got a lot going on here. Since you say you are short on cash (who isn't) , lets do something that won't break the bank.

You mention having a later model distributor on the motor. Give us the part # off of it. If you have a smog era distributor your advance is going to be way slooow. You might get lucky by being able to change out advance springs to get things moving a little quicker. A member here Halifaxshop rebuilds and can recurve distributors if needed. But a spring kit is super cheap and it requires very little work. There is a guy out west 4 sec flat???? He sells advance limit plate that makes things super easy to change advance limits without having to weld up advance slots. Plus make sure your weights move easy and are lubed at pivot points.

The information others have given in my opinion spot on with cam shaft info etc. A decent roadrunner cam profile would make the car run good, I believe the summit cam mentioned is close to rr specs, you'd have to double check tho.
The early pushrods are tapered at both ends, and yes if you use later lifters the spring cups are different, and the early push rod will sit deeper in the cup effecting overall lift #s. If this is the case, I'd be leery of pushrods possibly moving around too much, maybe pop out at high rpms??? Not sure on that, but you never know.
Carb is a little small, but as others have said comp check, verifying cam install all these bits are great starts.
Best of luck, let us know how things go for you
 
I wouldn't use a cam with anymore than 60 degrees of overlap. the summit 6401 cam is at least one step more than a stock cam. the summit 6400 is basically a stock magnum cam with a tighter lobe separation; 112 vs 115. the comp cams 280 is a good performance choice. the howards 720141-12 might be a real good one too. the [email protected]/.480 cam lobe I mentioned earlier is still available from howards. the mr. 6pak stuff used to be engles and I've used engle cams before. an engle k56 intake lobe/k58 exhaust lobe camshaft is an over achiever. I've used the mopar 272/.455 and found it to be somewhat an over achiever. lot's of stuff out there. stay with a 110-112 lobe separation angle and I wouldn't be afraid of a single pattern cam. I know when I was beating on 383's, back in the day, the more I cammed the worse it ran. your 600 edelbrock may not be the best choice either. the 650 is nearly identical in size to the old '68 and later 383 avs. mr. gasket sells a .020" steel shim head gasket, #1135g.
 
I plugged the numbers into my spread sheet, and Compression ratio should be about 9:1 (8.99:1 calculated), but that assumes a 84cc head volume, and stock heads can measure larger. Also, assumes 9.98" deck height with the piston (not dome part) sitting -0.024" below block deck, and a 0.040" 10cc gasket volume.

On a compression check (all spark plugs out, carb wide open), I think you should see about 130 PSI? based on cam specs.

The cam is not ideal, but it sounds like the engine has other issues?
If you used the stock early pushrods with the tapered ends, they will be too long in length. usually, even the later stock pushrods are a bit long for the cams I have used.

It also sounds like you may have tuning to do on the carb and ignition.

On the Carter/Edelbrock carbs, the issue I have had with those is getting the fuel level set correctly. If the fuel level is too low, it will act lean with a weak accelerator pump shot.
I run the engine to make sure the fuel pump has filled the carb fuel bowls, then shut the car off and remove the top of the carb. The fuel should be at the level of the plate that seperates the primary and secondary jets. If below that correct the float level, or check/adjust the fuel pressure.

On the ignition, I use a dial-back timing light. Check how much timing is in the mechanical curve. Do this by disconnecting the vacuum advance, and record the ignition timing at idle. Then rev the engine to about 3,000 RPM until the ignition stops advancing and record the timing. The difference is the amount of timing in the mechanical advance curve.
You may want to limit this advance to 20 degrees. This way you can set initial advance to about 16-degrees, and have 36-degrees total advance. How fast the advance comes in is controlled by the springs, and I start with one heavy spring and one light spring.
 
thx
i didn't check cranking psi checked the carb it was full of rust dust got that cleaned out metering rods looked burt iI'll get a rebuild kit ASAP set the initial timing at 15 pluged vacuum advanced
breaking up or slugish top end
would msd ready to run be a good choice
also mid winter 770 street avenger been thinking thats the way to go
agian great forum thx
 
I wouldn't put a nickel in an MSD anything.

That's funny. I'll be using the old school 32 oz. Accel racing points. That's what the Pure Stock boys are using and highly recommended to me. But... you can't buy those anymore. Whenever a set pops up somewhere, I pick it up if the price is right.
 
If your carb is all mucked up, I'd get that nice and cleaned out like you mentioned. I'd try and figure out why that happened in the first place. You might need a fuel additive to keep ethanol at bay, take a pic or two of the float bowls once you get it taken apart.
You need to make sure your advance weights can move freely, and advance comes in a little sooner, hence figuring out which yr distributor you have. These two things alone, once dialed in might make your car more responsive and fun to drive, and to help out with the cam you have. OEM ignition once set up correctly should be more than sufficient for your engine. Since you are working within a budget, I'd focus on these 2 things first before going msd or some other high dollar system. If you had a super high hp motor and needed every ounce of power I'd say go msd or whatever. But at your level keep it simple. Its your call.
 
I went thru the ignition gadget craze years ago. people try to use some ignition gadget to cover up a poor tune-up or failing parts; can't do it. you can make an inductive system do everything you want. capacitive discharge is by far not a necessity. I don't use them and won't. people would be surprised to learn how well an old point system can run. myself I use the mopar stuff and may add a FBO box. people blow all kinds of money on gadgets but won't spend 15 minutes on good clean grounds, quality plug wires and the proper plugs. I stripped the garbage out years ago and haven't looked back.
 
thx
i didn't check cranking psi checked the carb it was full of rust dust got that cleaned out metering rods looked burt iI'll get a rebuild kit ASAP set the initial timing at 15 pluged vacuum advanced
breaking up or slugish top end
would msd ready to run be a good choice
also mid winter 770 street avenger been thinking thats the way to go
agian great forum thx

What condition are the fuel lines and fuel tank? When I got my '69 Coronet R/T Convertible it had the rust in the carb because the fuel lines were junk. Replaced them with the 3/8", 1/4 return stainless steel lines, and a new gas tank which was rusty and leaking around the vent lines.

On my low budget 383 that I built in the 1988, I used Ford 460 pushrods from Summit racing (summit brand) in the 383. They are 8.550" compared to the stock "B" 8.575" length. The Ford pushrods are a oil-through design, but seemed to work fine. Only $28.
https://www.summitracing.com/parts/sum-g6417/overview/
 
If you need a fuel tank, check Amazon. AMD showing the Spectra Premium one for $130
https://www.amazon.com/Gas-Tank-66-...615857&sr=8-2&keywords=1966+coronet+fuel+tank

There is also a Evan-Fisher? brand? I don't tnow that brand, but $106
https://www.amazon.com/Evan-Fischer...615857&sr=8-4&keywords=1966+coronet+fuel+tank

There are alot of new Distributors on the market, and I have not kept up with them. I have been converting more of my stuff to EFI where the EFI computer controls the ignition timing.
The MSD Programable 6AL-2 box lets you program in any advance curve you want, and you can just lock out the advance on the Distributor. If you did not have a Dist, you could even use a lean-burn dist from a late '70s (1977?) Cordoba 400 or like car. MSD has the box on sale for $352 + cost of a Map sensor.
https://www.msdperformance.com/products/ignitions/street_and_strip/parts/6530

Really, you can get a self tuning TBI EFI with ignition control (Holly Sniper or FI Tech) for about $1,000. The added cost here is you need the EFI fuel pump/fuel tank and return line, and a O2 bung welded in the exhaust, but if your lines/tank ar rusted and needs replaced, not that much difference in cost?

To me the EFI is more up-front cost, but saves on the cost of tuning. I have spent several hundred dollars (if not thousand) in jets, metering rods, air bleeds, accelerator pump cams, vacuum secondary springs, shooter clusters, and gaskets just to tune carbs. Plus chassis dyno time. The ignition, not as many parts, but time consuming to change the ignition curve.
 
i was in panic mode before this thread. i realize just need to slow down and be practical.

the distributor tags gone so not sure if it's smog yrs. but wouldn't mind some easy adjustability. cheaper then MSD is the flame thrower lll.

the tanks original looks ok lines also but ill check them out and replace if necessary maybe better fuel filter.
thx
 
If you are running an edelbrock out of the box its almost certain that the carb jet size is too small. You should look into a strip kit and try going up a couple jet sizes.
There's a big difference between running at 15 and 13.5 for an AFR. I would do this first, check cam timing and balancer zero mark, then you can address the timing. An AFR meter would be a great tool for getting the mixture dialed in.
 
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