Chevy Astro and GMC Safari Forum banner

HEADERS!! HEADERS!! HEADERS!!

25K views 65 replies 18 participants last post by  MilkTeaAstro  
#1 ·
the stock, original exhaust system on my '99 astro cargo 2WD is still in good condition but it's now 20 years old.
i wanted to research what i can replace the whole system with in 2019.
i thought writing up a post here would be a good way to organize what i've found and it might help anyone else with the same interest.

i'll start with a rundown of the stock exhaust system components with the GM part numbers.
i made the following searches as a 1999 astro cargo in 2WD and AWD versions.

cast iron exhaust manifolds (screen grabs from GM Parts Giant website)
i made searches for 2WD & AWD and got the same results :
mani1.jpeg

mani2.jpeg


left (driver's side) manifold part # 12552325 (screen grab from GM Parts Store because they have a downloadable full fitment list).
note manifold fits 1996 thru 2001 astro/safari, along with other vehicles :
manifolds2.jpeg

manifolds3.jpeg

manifolds4.jpeg

manifolds5.jpeg


right (passenger side) manifold part # 12550122 with fitment list from GM Parts Store.
note manifold fits 1996 thru 2005 astro/safari, along with other vehicles :
manifolds6.jpeg

manifolds7.jpeg

manifolds8.jpeg

manifolds9.jpeg


y-pipe with integral catalytic converter (first 2 screen grabs from GM Parts Store website):
cat1.jpeg

cat2.jpeg

same part number 1513680 still available at GM Parts Giant (searched as 2WD & AWD, got the same result):
cat3.jpeg

cat5.jpeg


muffler & tailpipe assembly (first 2 screen grabs from GM Parts Store website):
muff3.jpeg

muff4.jpeg

same part number still available at Arnie Bauer Cad/Buick/GMC (searched as 2wd):
muff2.jpeg


for roughly $1800 plus tax & shipping i can buy new GM exhaust manifolds, y-pipe with cat & the muffler/tailpipe assembly.
YIKES :eek: :eek: !!!!!

i'll upload the post here to make sure it goes in OK then i'll continue..............
 
#13 ·
chevymaher said:
Full sized truck headers fit. They got 4.3 headers.

If you look hard enough years ago there was a thread and they actually gave the part numbers for the unicorns that fit.
Is this the thread you're referring to? https://www.astrosafari.com/viewtopic.php?f=24&t=130034

I see some 1st gen astros with part numbers... will any header that fits the first gen clear everything on the 3rd gen? And does AWD have clearance issues that RWD doesn't?
 
#14 ·
I'm strongly considering headers, I already have a catback. Does anyone know for sure which headers fit a Gen3 AWD? I definitely do not want to find out they don't fit after I take off the manifold, lol.

The pacesetter and JBA headers in that thread look interesting, but I can't tell if the people who used them had an AWD van.
 
#15 ·
sorry guys, been away from posting lately.
for me in denver with the emissions testing program my header choices will be limited to direct fit short headers (they bolt up to the factory y-pipe/catalytic converter assembly).
a currently available, matched, short header set for sale for a '99 astro doesn't exist from any manufacturer that i could find.
using the info from the scans i loaded at the beginning of this post, i looked for direct fit headers for vehicles that were factory equipped with the same exhaust manifolds as the astro manifolds.
i found Pacesetter & JBA header listings that cross-referenced for one side or the other.
i didn't see any Pacesetter headers in stainless steel, but JBA had listings in stainless.
i focused on the JBA stuff from there because of the hopefully increased lifespan of stainless steel.

the available, applicable JBA listings for the cross-referenced left side header would be : 1996>98, Chevrolet/GMC, C1500/K1500, full size trucks.
the header set number is 1842SJS.
1842SJS_full.jpg

View attachment 1842SJS.pdf

the available, applicable JBA listings for the cross-referenced right side header would be : 1996-01, Chevrolet/GMC, S10 & S10 blazer, 4WD.

View attachment 1842S-3.pdf
1842S-3_full-1.jpg


JBA has discontinued production of these headers, that's why the left side number is for ceramic coated and the right side number is for bare stainless - that's all they have left.
the good news is that JBA will sell a mixed left/right header set from their available stock.
JBA only listed the S10 set in 4WD, but the GM manifold part number scans showed 2 & 4WD using the same manifolds.

i went ahead & ordered the headers with my tax return mad money, here's some pics :
hedd1.jpg

hedd2.jpg

hedd3.jpg

hedd4.jpg

hedd5.jpg

hedd6.jpg

hedd7.jpg

hedd8.jpg

hedd9.jpg

hedd10.jpg

hedd11.jpg

hedd12.jpg

hedd13.jpg

hedd14.jpg

hedd15.jpg

hedd16.jpg


will they fit ??
i don't know....... :shrug:
 
#17 ·
wow, those are pretty.

So you need a different left header and right header, rather than 1 set for 1 vehicle? sheesh. Still curious if they fit.

I'm considering the pacesetter 70-1355, but they're not stainless steel. However, I saw them on a 95 AWD in the thread I linked above, so I think they fit. After talking to Andy's autosport, they also offer the ceramic coated version:
https://www.andysautosport.com/products ... C1355.html (ignore the pic, they have the wrong stock photo, but their support was very knowledgeable)

If it fits a 95 AWD, it'll fit a 2004, right? I'm thinking of pulling the trigger
 
#18 ·
After talking with @akforceten about his 2000 AWD with the pacesetter headers, I'm going to give the ceramic coated version a try. He has a 3" body lift, but hopefully my 2" will be enough, only 1 way to find out. He mentioned that you'll need spark plug wires with 90 degree boots and a little Y pipe modification.

FYI, Rockauto has them (Pacesetter 72C1355) for $256, which is WAY cheaper than everywhere else.
https://www.rockauto.com/en/parts/paces ... eader,5848 (plus 5% off with the coupon in vendor row)
 
#19 ·
hi joeg,
for my situation (1999) the different left & right side headers i bought should theoretically bolt up to the factory y-pipe.
the bigger question is whether or not they will fit my van body/chassis, because the header designers evidently never test fitted their headers to an astro/safari.

for your situation (2004) the right side should be the same from 1996 thru 2005 (per my research they all used exhaust manifold part # 12550122), so the right side header of the set you're looking at should theoretically fit your y-pipe. it appears that the astro/safari left side exhaust manifold part # changed for 2002 thru 2005 (from old # 12550122 to new # 12570693). i haven't researched this newer number to try & figure out what is different. looking at the thread you referenced, one of the posters spoke of an S10 left side header needing to be reworked to fit the astro body & it did not fit the y-pipe.
 
#22 ·
If you are going to go to all the trouble of installing expensive performance headers.. why not consider true dual exhaust?

This photo always impresses me!
(tube size in this photo might be wrong for a V6)

Dual Exhaust.jpg

Here's another one (not mine):

FromDellputer180.jpg

Long (proper diameter) pipes (BEFORE mufflers) are instrumental in scavenging effect and flow... just as they are in the header design. If not dual-mufflers, then maybe something like this??

CIMG1351.JPG

I guess these examples don't show cats, but I'm sure they'd fit too.
(Note: not my photos)
 
#23 ·
Mmusicman said:
If you are going to go to all the trouble of installing expensive performance headers.. why not consider true dual exhaust?

This photo always impresses me!
(tube size in this photo might be wrong for a V6)

View attachment 2
Here's another one (not mine):


Long (proper diameter) pipes (BEFORE mufflers) are instrumental in scavenging effect and flow... just as they are in the header design. If not dual-mufflers, then maybe something like this??

View attachment 1
I guess these examples don't show cats, but I'm sure they'd fit too.
(Note: not my photos)
As cool as that would be, would there really be any gain over the 2.5" catback setup I have now? It would rack up a lot more cost, plus I've already paid for my current setup. The headers were only $250. My thinking is that the biggest restrictions are the exhaust manifolds, the Y pipe, and the cat, since I already have a freeflowing muffler and 2.5" from the cat back.
 
#25 ·
Mmusicman said:
Yes the biggest improvement IS the headers!
Best bang for the buck!
Esp if you could get long tubes to fit in there.
 
#26 ·
Here are the Pace Setter Part# 72C1355 headers. Mild steel with "Armorcoat" ceramic coating. Pretty nice for $250. They're even CARB certified, which is kind of crazy for that price. Too bad nothing else on the van is because it started life on the East Coast where the laws are more relaxed, lol.

Image

Image

Image

Image


Thanks again to @akforceten for paving the way on these in another thread.

I'll update the thread after I get around to installing them.