Simon Juncal

Ervin Charles wrote:
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play toy...

You need a 4.0 header, the cheapest are on ebay Stainless steel for
around 50 bucks, these are just direct rip offs of OEM tube header with
the accourdian flange to eliminate the cracking problem on the long tubes.

You then need welding skills or a muffler shop to do your collector
pipe, your old one more than likely wont be even close to the header's
output. The 4.0 collector pipe (or "down pipe") is on the wrong side and
routed differently from the YJ and most likely the CJ.

--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein

Simon Juncal

Ervin Charles wrote:
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play toy...

You need a 4.0 header, the cheapest are on ebay Stainless steel for
around 50 bucks, these are just direct rip offs of OEM tube header with
the accourdian flange to eliminate the cracking problem on the long tubes.

You then need welding skills or a muffler shop to do your collector
pipe, your old one more than likely wont be even close to the header's
output. The 4.0 collector pipe (or "down pipe") is on the wrong side and
routed differently from the YJ and most likely the CJ.

--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein

Simon Juncal

Ervin Charles wrote:
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play toy...

You need a 4.0 header, the cheapest are on ebay Stainless steel for
around 50 bucks, these are just direct rip offs of OEM tube header with
the accourdian flange to eliminate the cracking problem on the long tubes.

You then need welding skills or a muffler shop to do your collector
pipe, your old one more than likely wont be even close to the header's
output. The 4.0 collector pipe (or "down pipe") is on the wrong side and
routed differently from the YJ and most likely the CJ.

--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein

Rich

I did the swap. It's well worth it. Use a 4.0 exhaust manifold or
aftermarket header. Boorla makes one that will bolt right up. You have to
call them and tell them what your doing and they will take allot of your
money in exchange for an excellent product. I was a cheapwad and went the
cheap route with a $75.00ish aftermarket header. I bolted everything
together then went to the local muffler shop where they made me a collector
pipe to go to the muffler. Don't forget to get the O2 sensor installed if
you need one. The muffler shop charged me something like $50.00 for the pipe
and installation.
Doing the head swap was well worth it. CAUTION! Don't just throw the old
rods and rockers back on before measuring the whole shooting match. I had to
have custom pushrods made. It was another $100 at Crower cams in San Diego.
They were real helpful. They gave me an adjustable push rod and a solid
lifter to use for measurement.
My Power and economy are way better than before. I gained about 3-5mpg
depending on how I drive it and a ton more power. Unfortunately my power
gains make me use the skinny pedal more just for the fun of it. Ruins the
gas mileage gains....
Rich
"Ervin Charles" <charleserv@charter.net> wrote in message
news:DX5Rf.671$ts.643@fe05.lga...
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play
> toy... I need to find a header that will be compatible with this swap. Has
> anyone out there done this swap and, if so, which header or manifold did
> you use. I've read Tim Weavers article on the swap but info on the exhaust
> set up is pretty vague and not really applicable to my 1984 model. (Bill,
> if you could step in here it would be greatly appreciated!) Thanks in
> advance for any and all replies...
> Charles
>
> 81 DJ5L
> 84 CJ7
> 92 Cherokee
>

Rich

I did the swap. It's well worth it. Use a 4.0 exhaust manifold or
aftermarket header. Boorla makes one that will bolt right up. You have to
call them and tell them what your doing and they will take allot of your
money in exchange for an excellent product. I was a cheapwad and went the
cheap route with a $75.00ish aftermarket header. I bolted everything
together then went to the local muffler shop where they made me a collector
pipe to go to the muffler. Don't forget to get the O2 sensor installed if
you need one. The muffler shop charged me something like $50.00 for the pipe
and installation.
Doing the head swap was well worth it. CAUTION! Don't just throw the old
rods and rockers back on before measuring the whole shooting match. I had to
have custom pushrods made. It was another $100 at Crower cams in San Diego.
They were real helpful. They gave me an adjustable push rod and a solid
lifter to use for measurement.
My Power and economy are way better than before. I gained about 3-5mpg
depending on how I drive it and a ton more power. Unfortunately my power
gains make me use the skinny pedal more just for the fun of it. Ruins the
gas mileage gains....
Rich
"Ervin Charles" <charleserv@charter.net> wrote in message
news:DX5Rf.671$ts.643@fe05.lga...
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play
> toy... I need to find a header that will be compatible with this swap. Has
> anyone out there done this swap and, if so, which header or manifold did
> you use. I've read Tim Weavers article on the swap but info on the exhaust
> set up is pretty vague and not really applicable to my 1984 model. (Bill,
> if you could step in here it would be greatly appreciated!) Thanks in
> advance for any and all replies...
> Charles
>
> 81 DJ5L
> 84 CJ7
> 92 Cherokee
>

Rich

I did the swap. It's well worth it. Use a 4.0 exhaust manifold or
aftermarket header. Boorla makes one that will bolt right up. You have to
call them and tell them what your doing and they will take allot of your
money in exchange for an excellent product. I was a cheapwad and went the
cheap route with a $75.00ish aftermarket header. I bolted everything
together then went to the local muffler shop where they made me a collector
pipe to go to the muffler. Don't forget to get the O2 sensor installed if
you need one. The muffler shop charged me something like $50.00 for the pipe
and installation.
Doing the head swap was well worth it. CAUTION! Don't just throw the old
rods and rockers back on before measuring the whole shooting match. I had to
have custom pushrods made. It was another $100 at Crower cams in San Diego.
They were real helpful. They gave me an adjustable push rod and a solid
lifter to use for measurement.
My Power and economy are way better than before. I gained about 3-5mpg
depending on how I drive it and a ton more power. Unfortunately my power
gains make me use the skinny pedal more just for the fun of it. Ruins the
gas mileage gains....
Rich
"Ervin Charles" <charleserv@charter.net> wrote in message
news:DX5Rf.671$ts.643@fe05.lga...
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play
> toy... I need to find a header that will be compatible with this swap. Has
> anyone out there done this swap and, if so, which header or manifold did
> you use. I've read Tim Weavers article on the swap but info on the exhaust
> set up is pretty vague and not really applicable to my 1984 model. (Bill,
> if you could step in here it would be greatly appreciated!) Thanks in
> advance for any and all replies...
> Charles
>
> 81 DJ5L
> 84 CJ7
> 92 Cherokee
>

Rich

I did the swap. It's well worth it. Use a 4.0 exhaust manifold or
aftermarket header. Boorla makes one that will bolt right up. You have to
call them and tell them what your doing and they will take allot of your
money in exchange for an excellent product. I was a cheapwad and went the
cheap route with a $75.00ish aftermarket header. I bolted everything
together then went to the local muffler shop where they made me a collector
pipe to go to the muffler. Don't forget to get the O2 sensor installed if
you need one. The muffler shop charged me something like $50.00 for the pipe
and installation.
Doing the head swap was well worth it. CAUTION! Don't just throw the old
rods and rockers back on before measuring the whole shooting match. I had to
have custom pushrods made. It was another $100 at Crower cams in San Diego.
They were real helpful. They gave me an adjustable push rod and a solid
lifter to use for measurement.
My Power and economy are way better than before. I gained about 3-5mpg
depending on how I drive it and a ton more power. Unfortunately my power
gains make me use the skinny pedal more just for the fun of it. Ruins the
gas mileage gains....
Rich
"Ervin Charles" <charleserv@charter.net> wrote in message
news:DX5Rf.671$ts.643@fe05.lga...
> Hey group,
> I have ordered a 4.0 head to go on my 84 CJ7 4.2, Manual Trans play
> toy... I need to find a header that will be compatible with this swap. Has
> anyone out there done this swap and, if so, which header or manifold did
> you use. I've read Tim Weavers article on the swap but info on the exhaust
> set up is pretty vague and not really applicable to my 1984 model. (Bill,
> if you could step in here it would be greatly appreciated!) Thanks in
> advance for any and all replies...
> Charles
>
> 81 DJ5L
> 84 CJ7
> 92 Cherokee
>