Conference ssdevo::4wd

I've got a cj5 with a Chevy 283 V8 in it that needs
some A.I.R. stuff put on to make it pass CO emissions
next time around.

The question I have is about chevy heads and what
type of exhaust manifolds I could put on this thing.
Right now its got some headers on their last legs, so
its time to do something about it anyway.

To my thinking the cheapest way out of this would
be to put on some salvage yard chevy exhaust manifolds 
with air tubes already on them, and then have the exhaust
shop run new tubes to a stock Jeep V8 single rear exit
muffler/exhaust.  I'm not sure at this point what type
of clearance problems I'm going to run into, until I
get a look at said manifolds and where they exit
to the tubes.  The farther toward the rear of the block
the better off I'll be I think.

Anybody got any tips on what I should look for when
looking for exhaust manifolds like this?  Are there
any differences in heads in terms of port sizes/spacing
or have they remained standard?  What years of chevy
v8s had air tubes on them....I'm thinking something like
75-78?

--Bert

    I remember that you could get headers with air tube connections on
    them.  You might check for this before you go and put regular exhaust
    manifolds back on. 
    
    Steve m..

    Why bother?  Just get an entire used 305 with all the emissions junk on
    it and be done with the hassle of all that matching up etc.?
    
    'Sides, a few extra 'cubes never hurt nuthin' either... 8^J
    
    Good Luck.

good suggestions, but...
there is the monetary aspect to consider.  

If I get some new headers with air tubes, I'd be
lucky if they cost what $250-$300 for the pair?
Plus I still have the rest of the custom exhaust
to do.

An engine swap just to get some exhaust air tubes?  I'd
still have the custom exhaust to do after that too.

I've already got the air pump, hosing, and backfire
valve on the jeep so its' about 50% there if I 
can just get it all connected to some air tubes
feeding into the exhaust ports.

I was thinking something along these lines to keep it
cheap.

2 Salvage exhaust manifolds with tubes       $50/each
Stock rear exit jeep exhaust/muffler (new)   $80
Catalytic converter (already have one)       $0
Air pump/backfire valve/hoses (already have) $0
Custom exhaust from manifolds to cat	     $100

If I can manage all this, I'd be looking at less
than $300 for the whole rework, and be able to
re-pass emissions.

The 283 is plenty of muscle in this little 77 cj5
so I'm not concerned about any horsepower loss 
I might get from a single exhaust vs headers/duals.
In granny low, it dont matter much, and at 65mph
you need to be wearing a diaper, and in the middle range
you can burn the tread off the tires, so whats a few
horses compared to dollars?  8^}

So, that said am I looking at an impossible task
to match some manifolds to the heads?  Are there
huge variations year by year, or have they remained
fairly standard?  I want to think standard, because
when I look at exhaust manifold gaskets, the same 
gasket seems to cover a wide range of years and
engine sizes (like 1957-1980 265-350 V8).  Now that 
I think about it, I guess I could drop a header and 
take an old gasket with me if I can get off intact 
and have a pattern to match any prospective manifold.

--Bert

    re. .50
    
    Hey the old CJ's are unstable at lotsa speeds, that's what roll cages
    and harnesses are for.
    
    Geeze Louise...engines must be expensive in your neck o'woods...
    
    A used air pump 305 with all the trinkets on it should go for
    something in the $3-500 range.  What you're talking about is gonna 
    go for that kinda money and you've still got the old engine.
    
    305 is a 1-4-1 swap in terms of external dimensions, bolt-up etc. why
    do you need new headers if you have old ones?  327 is the same too
    unless you're into a Vette engine... lotsa wierd heads and manifolds.
    
    Oh well... if you're a trinket-ologist, that's O.K. too, but it's gonna
    take some time and multiple visits to get all the trinkets you need.
    
    Good luck finding all them trinkets used in good condition... the good 
    ones are usually sold with complete good engines and the yards don't 
    like folks picking stuff off of good engines because the trinkets keep
    the ports sealed up and crud from getting in.  Besides, engine swappers
    tend to lose or wring off something or other and the complete engine
    is a lower hassle sellable item.
    
    
    Regards,