383-2bbl from 68 newport

[my1st68charger]

I have a 383 2 bbl from a 68 newport ,runs awsome.I would like to put it in my 68 charger ,and put a 4bbl on it.Any ideas on this,is there anything i should know before i do this?

[Challenger340]

You may wish to consider a Camshaft upgrade, when switching to the 4 bbl Carb, if you are looking for 4 bbl "power".

The Factory Camshaft used in the 383 2 bbl Engines, was noticeably smaller than the 4 bbl engines, therefore simply installing the 4bbl Carb & Intake without upgrading the Camshaft, is usually a dissappointment,
unless your just looking for appearances.

[my1st68charger]

I'm looking for power but not super high performace ,will a stock 4bbl be good enough you think?

[Challenger340]

A Stock 4bbl will be fine, But without a Camshaft change, the 4bbl will do "squat" for power.
You need to change the Cam as well.

[TylerCharger69]

Also may want to consider what was in the car before hand....If it was a 318 car...the upper motor mount hardware is different.  There are a lot of pics in this forum that can show you what's proper.  I'd also consider upgrading to an electronic ignition as opposed to points distributor.  On that cam....find out what the stock profile on a 383 4 bbl is.  (I don't remember off the top of my head).  The stock 2 bbl profile won't fit the 4 bbl upgrade very well.  Assuming this 383 engine is bone stock of course....Ace

[my1st68charger]

This is a untouched 68 383 2bbl from a newport .
This car was only summer driven by a priest ,never beaten ,it dont even smoke.I'm still going to check it all out ofcourse and install new gaskets etc.After three years of working on this car its nice to be playin around with this stuff now.Oh yeah my car is a 68 charger and its a 383 car.

[John_Kunkel]

Keep in mind that the 383-2 has nearly a full point less compression than a comparable 383-4 and that the actual compression ratio is usually a half-point lower than the factory advertised.

Even with a 4-barrel and mild cam it'll never match the power of a factory 383-4.

[SeattleCharger]

Keep in mind that the 383-2 has nearly a full point less compression than a comparable 383-4 and that the actual compression ratio is usually a half-point lower than the factory advertised.

Even with a 4-barrel and mild cam it'll never match the power of a factory 383-4.

is it the same block?   could you change head gaskets, (narrower ones)  or put on different heads, . . .  up the compression that way?

[my1st68charger]

I have a 383 4bbl ,but it is sized .I have to look and see if its a HP, I was thinking about taking the heads off of it .Maybe cam too.

[green69rt]

This is a untouched 68 383 2bbl from a newport .
This car was only summer driven by a priest ,never beaten ,it dont even smoke.I'm still going to check it all out ofcourse and install new gaskets etc.After three years of working on this car its nice to be playin around with this stuff now.Oh yeah my car is a 68 charger and its a 383 car.

Unless there's something wrong with the existing engine then I don't think you'll be doing yourself any good with the swap.  Better to spend your money on cam, exhaust, intake and carb for the existing engine.  If you want to spend the bucks(and the engine won't go into your car for a while), the two things that I would do is get a new cam and see if you can find some 383 4bbl heads ( I think the valves are bigger and the compression is higher.)  Also since the engine will be out of the car, now is the time to drop the oil pan and add a windage tray ($20? maybe someone out there knows??) and a hi flow/hi press oil pump, cheap insurance for later.   I'm sure some of the folks on this thread can steer you to the correct setup.

[my1st68charger]

With 4bbl heads ,a new cam,intake ,carb,oil pump,and headers I should be ok.What size of carb should i run?650??

[green69rt]

With 4bbl heads ,a new cam,intake ,carb,oil pump,and headers I should be ok.What size of carb should i run?650??

All that sound reasonable and you don't have to do it all at once.  Don't forget the windage tray (worth 5 or 10 HP).

650 range would probably be fine unless you're going racing. Be careful of your vacuum because once you get up in the 800 cfm range or the cam gets a lot of overlap it's hard to maintain vacuum and you'll need a high stall converter to keep the idle at a reasonable level.  IMO

[my1st68charger]

I won't be doing any racing with it ,I just want to drive and enjoy the car,but i still want it sound good and have respectable power.I've been working way too long on this car to be beating it up.

[my1st68charger]

Thankyou all for your help
What about a converter

[green69rt]

Thankyou all for your help
What about a converter

Probably no reason to change the converter.  But.... as you get some bucks, add a deep sump transmission pan ( it comes with a filter converter to take advantage of the deep pan.  It will also have a drain plug to make transimssion oil changes easier.  This will make the transimission run cooler and help it withstand the additional HP.

Realy a lot of realitively easy bolt on swaps that will add some significant HP and reliability.  Let us know how things go.  This is hot rodding it it's most basic form!!

Good luck.

[SeattleCharger]

as long as you have the engine out it would be a good time to do the converter, though.  maybe a 2500 stall?  couple hundred bucks.  If you do it later, you will have to pull the engine, or engine and trans,  

  having a taller stall will let you get a little bigger cam and intake without having to worry as much about losing your low end performance, 

[John_Kunkel]

is it the same block?   could you change head gaskets, (narrower ones)  or put on different heads, . . .  up the compression that way?

Same block, same heads (906), same thickness gasket. The '68 and '69 383-4 pistons are near zero deck while the 383-2 is down in the hole.

[green69rt]

I did a search on this site for "383 Magnum" and came up with a bunch of stuff that will help you.  Personally, I'm a little supprised to find that the 383 4BBL and the 383 roadrunner engine are essentially the same.  From the notes I see the 383 4bbl heads and the 440 heads ( after a certain year ) are not any different so are they worth the money....?  You read the threads and you make a choice. 

The other stuff about cam,carb, intake and exhaust still hold.  Have fun and enjoy the process. 

[my1st68charger]

is it the same block?   could you change head gaskets, (narrower ones)  or put on different heads, . . .  up the compression that way?

Same block, same heads (906), same thickness gasket. The '68 and '69 383-4 pistons are near zero deck while the 383-2 is down in the hole.

Do you mean if I change heads and cam its still not the same as a original 383 4bbl?

[SeattleCharger]

depends what thickness the gaskets are in this equation also.   is the 383-4 zero deck because the pistons go up a lot farther, but still has a gasket that is thick enough to put in a much thinner one?   zero deck doesn't automatically mean no gasket width to speak of, does it?

[my1st68charger]

How do you think it would perform if I were to change  the cam ,heads , (650carb  maybe?)etc,would it hesatate or anything like that?

[green69rt]

How do you think it would perform if I were to change the cam ,heads , (650carb  maybe?)etc,would it hesitate or anything like that?

Not if you set them up right.The problem is that most of the stuff you're talking about will change the fuel mixture to the cylinder, so you'll have to think about that as you go along.  For example; if you put headers on this will tend to lean out the engine so you will need to re-jet the carb to compensate.  Cam change can do the same.

After thinking about what I just said, I think, as a first step, I would go with a new intake and carb.  This is probably the simplest swap you can make mechanically and will get you some performance improvement.  Spend the time to get the mixture right.  Also the timing of the opening of the secondaries is important.   Find somebody with some experience.  There's a lot of art and science around carb tuning and this will prepare you for the changes you want to make later. FWIW

[John_Kunkel]

Do you mean if I change heads and cam its still not the same as a original 383 4bbl?

Nope, the heads are the same, only the valve springs differ, so the compression will still be the same. The higher compression in the 383-4 comes from a taller piston, not the chamber size. Production big blocks all used the steel shim type head gasket so the only way to change that is to go thicker which would kill more compression.

To turn a 383-2 into a 383-4/Magnum you need the HP pistons along with all of the other parts like the cam, carb, exhaust manifolds, etc.

[my1st68charger]

I think i'm almost better to leave the motor the way it is and build another 383 hp block.

[green69rt]

I think i'm almost better to leave the motor the way it is and build another 383 hp block.

It is the best way to build a performance motor if you can put out the bucks.  But now you're talking about a complete rebuild of the motor.  When you go in you'll think " a quick cam, piston change, springs for the valves and I'm back in business."

Here's how it might go.... "blocks apart but the main, rod and cam bearing are old and I scared up a couple getting the engine apart so maybe new ones are in order, and while I'm in the engine a new oil pump sounds good.  Oh, that timing change has some slack in it so another $200 (I may be optimistic) is not that much.  Oh, and the block has a ridge at the top of the cylinders that needs to be cut out so if I'm reworking the bores why not give it .030" over and"  and on and on it goes.  Not trying to be discouraging but do the planning and decide what you want and be prepared for the "surprises".