Topic: IMCO vs Open Emissions

[Stangly]

Can anybody explain the difference between IMCO and open emissions systems.  I'm looking at a used carb and the number is C8ZF-D  Mustang Tek shows it for 302 4V for/c4 and IMCO.  They show another for 302 4V for auto trans C8ZF-A  The car I need it for is a J-Code with a c4 trans.

Thank you,

[J_Speegle]

IMCO has a number of different explanations - depending on what year its being used. Can look up the official wording if needed - have allot of period emission/smog books around the office.

Looking at the Ford Carburetor Guide that Pony carbs published many years ago it lists only the -D for automatics. This matches what my MPC printed April 68 shows also - no mention of a C8ZF-A. Also checked in the section that lists the engineering number for cross referencing and no C8ZF-A is shown


Since the emission standards were the same across the states that year (no special California stuff) all 302 4V Mustangs would have had the IMCO system that year and model.

[TLea]

C8ZF D is correct for J code auto. All J code autos are IMCO

[Stangly]

Excellent to hear guys, I just picked this car up for my son.  It is a San Jose car and spent most of its life in Stockton.  I am weighing my options on whether I want to to do a full conours restoration on the car.  From the little research I have done I know it would have been equipped with the emissions system.  The car is a j-code coupe and the body is in excellent shape and for the most part original except for the engine.  The dilemma is that I know that emissions for this car are some of the same that the GT350 uses and I don't know if I want to stick that kind of money into a coupe.  I'm kinda of thinking of doing the car as concours as I can except for the emissions to save some money.  I'd really like to go all the way with it but am not sure if it is feasible.  Thank you both for the info and any thoughts on the restore would be greatly appreciated.

David,

[krelboyne]

I believe that the cars sent to Canada in 1968 still used the open emissions system. (in most cases)

In 1968 for the US market, if it had a manual transmission or a Holley carburetor it had a thermactor smog system.

Automatics with Autolite carburetors should all have IMCO systems.

[TLea]

  The dilemma is that I know that emissions for this car are some of the same that the GT350 uses and I don't know if I want to stick that kind of money into a coupe.  I'm kinda of thinking of doing the car as concours as I can except for the emissions to save some money.  I'd really like to go all the way with it but am not sure if it is feasible. 

Yes it is identical to 350 as far as emissions but its not expensive at all. Emmisions consists of correct carb, distributor, PVS and PCV. I assuming the correct heads are still with car

[Stangly]

No the engine that came with the car was a hodge podge of parts.  The block was the correcet C8OE-A but not numbers matching.  The heads and intake manifold were for a 289 2V.  So what your saying the big expense would be the heads, to do it completely concourse, how about the intake manifold. 

[Bossbill]

1968 IMCO explained in a shop tech tips:
http://www.mustangtek.com/Library6/PDF/ShopTips6-1.pdf

[RoyceP]

The '68 302-4V heads are not hard to find or expensive but they have a small 65 - ish CC combustion chamber that is not happy with stock pistons and today's gas. You might be better off using the heads that you have if they are lower compression. Find the correct 1968 302-4V intake and no one will be the wiser. The stock intake is also not hard to find - check with WCCC they normally have a selection of date codes available.

No the engine that came with the car was a hodge podge of parts.  The block was the correcet C8OE-A but not numbers matching.  The heads and intake manifold were for a 289 2V.  So what your saying the big expense would be the heads, to do it completely concourse, how about the intake manifold.

[Coralsnake]

Am I missing something the posts are 9 years old and very incorrect, why are we bringing these up?

[preaction]

The '68 302-4V heads are not hard to find or expensive but they have a small 65 - ish CC combustion chamber that is not happy with stock pistons and today's gas. You might be better off using the heads that you have if they are lower compression. Find the correct 1968 302-4V intake and no one will be the wiser. The stock intake is also not hard to find - check with WCCC they normally have a selection of date codes available.

68 302 4bbl heads have a 53.5cc head.

[RoyceP]

I read that some place too but the ones I measured - mine -  were more like 64 CC average. I think the 53.5 CC might be NHRA minimum after milling. In any case not a desirable size for using today's crappy 91 octane super unleaded. These heads were made for 100 octane leaded premium.

68 302 4bbl heads have a 53.5cc head.

[Bossbill]

Am I missing something the posts are 9 years old and very incorrect, why are we bringing these up?

I was wandering around the site to get more up to speed about IMCO. Found some data that came directly from Ford.

There is always the issue of do I start a new thread or add to an old one. I prefer to add on