So my car came to me without the exhaust connected to the manifolds (there was also no trans or engine in it). We had to drag the exhaust on the ground while manuvering the car out of the shop, onto the trailer, down my driveway and into my garage ... so there's a possibility that I could have bent up my Y pipe ...

So I spend an hour or two trying to get my Y-pipe bolted up to my manifolds, and try as I might, I can bolt up either one side or the other ... So the driver side manifold will bolt up, or the passenger side manifold will bolt up, not both at the same time.

So my question is ... if I go get a 90amp harbor freight welder and a helmet, would it be worth me trying to correct my stock stainless Y pipe, or should I spend roughly the same amount and get a new Y pipe from autozone/jegs/summit/other?

From what I can tell, this car already has some sort of catback system with aluminized piping from the outlet of the cat back. I have the cat and Y-pipe all disconnected and I can easily take my pipe over to an exhaust shop to have the cat welded onto my new Y pipe if I go that rout.

I am just curious what would be the best thing to do ... I haven't started this new engine/trans combo yet, but I'm considering doing it with open headers so i can pull it out of the garage for a little extra space. The only thing I need to do is fill up the fluids, install the driveshaft and figure out the exhaust then she's good to go .. I think.

Also it's possible I have a set of truck manifolds ... do the outlets on those manifolds line up with the stock third gen A.I.R manifolds? Cause they sure looked identical. Mine have no A.I.R btw.

Lets hear some ideas!

 

Oh, also here's some pictures of the Y-pipe/cat in question:

I took it off of the car to cut the messed up heat shields off ... saving myself an exhaust rattle in the future


I used the pipe cutters to put a crimp in the A.I.R tube


And here is the other side


From what I see, the pipe looks okay .. but bolting it up sure is a pain ...

Also, here's my manifolds after being blasted:


Really, the manifold that's on the bottom there is the one that doesn't want to bolt up the worst ... I have a hard metal exhaust doughnut/gasket thing carquest sold me that doesn't really seem to fit, even when I do get it bolted up .. kinda sorta.

I dunno. Something's weird, and I'm not sure which part(s) to blame.

 

It looks like that bottom manifold is supposed to have some sort of heat riser bolted between the Y-Pipe and it. Notice the flat base where as the other has the tapered fit for the Y-Pipe. If I remember right it is about 1 1/2 to 2 inches thick.
Does a spacer sound like the answer?

 

Not sure what it's original intended purpose was, but it's a chunky cast-iron donut that fits between the manifold and the stock y-pipe. You can just see it in the attached pic.

 

On carbed cars, on the pass side there was a EFE valve between the Y-pipe and the manifold. On TPI cars there was a simple spacer (which looks like the EFE valve without the butterfly). Some may have been equipped with a donut, but I uncertain of that.

JamesC

 

Ah, mine used to be a TPI, explains it. 'Spacer' is a better word for it than 'donut'.

If it or the EFE valve not there, the Y-pipe certainly won't bolt up.

 

the exhaust looks like LG-4/LO-3 but the manifolds look like L-69/TPI ... You can't interchange the two.

 

see the difference

 

Okay I was sorta afraid of that ... my manifolds were pulled by someone else from an unknown thirdgen and given to me when I got the car from the P.O. Mine is from factory with the 305 L03, and that's the factory Y pipe and cat as far as I know. So it has the L03 in it with TPI style manifolds??

So my options are ...? Buy a TPI Y pipe and cat, replace one or both of my manifolds (I even paid $40 to blast and paint these things ), or get a set of headers with a matching Y pipe?

The reason I got these particular manifolds is because one of the stock ones went missing ... I think I might be able to get it, because I think I know who has it. So ... maybe I should try using stock L03 manifolds then? How can I tell the difference?

Btw, thanks for all the responses, guys! I really appreciate the help

Oh, I might also be able to get a stock TPI Y pipe and cat off of a buddy of mine who is parting his car.

 

I probably shouldn't comment but the only difference I see is that one seems to be turned out more. (Could just be the way they are sitting in relation to the camera) They are both requiring that spacer.

 

id just go ahead and get headers and a matching y pipe. increased power and it wont be a pain in the a**.

 

ok here is O/P's Y-pipe. Notice passenger side inlet comes up and bends forward?



so needs this manifold to match it.



here is one it looks like he has in a different angle shot and you can clearly see the difference

 

Okay I think I see the difference ... well I just ordered one of those cast exhaust pipe adapters like #4 and #5 posts say I need. It was $16 off of ebay, so even if it doesn't help anything, it doesn't hurt.

So could I get away with getting a new passenger side manifold then? Do I have a TPI set of manifolds or TBI set of manifolds?

Honestly, I'm very close to just driving the thing open headers over to the exhaust shop and having them make me a Y pipe to fit.

 

You have TPI manifolds, any muffler shop should be able to cut the passenger side bent section and weld on a straighter section like TPI has so it will fit your manifolds you have. They flow better then TBI ones anyways, think TPI outlets were 2 1/2 while TBI was 2 1/4 or 2" .... Your better off with TPI exhaust anyways it all flows better then TBI. Maybe you can find a whole TPI exhaust at a wrecking yard or something. I am not sure of TPI's overall diameter difference from TBI but I know it is a very noticeable difference. Kinda think TBI is a 2 1/4 complete exhaust and TPI is somewhere close to 2 3/4 or 3"

 

maybe a TPI guy can share a pic of his front y-pipe.

 

Hmm maybe that's what I'll do then. Last time I went over to the particular exhaust shop that I'm thinking of going to, they wanted to (and successfully sold, btw. Not a bad decision either) sell me a complete $400 manifolds back system for my truck. It only had a hole in the tail pipe section with a patch on it, but the flange rusted off of the Y pipe. That was the only issue with it. It was aluminized piping, but they told me that they can't weld stainless pipe.

I'm wondering if they will want to modify my stock Y pipe instead of sell me a new one ... either way, I'd like to run a catalytic converter. I have the stock TBI converter that came with the car. I live in Detroit, so it's not like I need to run a converter ... but I'd like to anyways. It's likely that they'll want to sell me a Y pipe with a test pipe on the end and just weld it onto the catback that's already on the car.

I do like the idea of the little fitting on the end of the cat and the cat back system though ... I wonder if they can preserve this fitting. Is it even worth trying to keep that little bolt together fitting on the end of the cat?

 

Don't recall where I found this:

There were only 2 different manifolds for the V8's throughout the years, but they were different depending on what motor and gearing package they came on. Here is the breakdown.

2" outlet manifolds with single 2 1/4" y-pipe
82-87 305 LG4 (VIN H)
88-92 305 L03 (VIN E)
82-83 305 Crossfire
90-92 305 LB9 w/o G92 axle (VIN F)

2 1/4" outlet manifolds with single 3" y-pipe
83-86 305 L69 (VIN G)
85-89 305 LB9 (VIN F)
88 350 L98 (VIN 8)
89 350 L98 w/o G92 axle (VIN 8)

2 1/4" outlet manifolds with dual 2 1/4" cats
89 350 L98 w/G92 axle (VIN 8)
90-92 350 L98 (VIN 8)
89 305 LB9 w/G92 Axle (VIN F)
90-92 305 LB9 w/G92 (Vin F)

JamesC

 

Dorman still offers the good manifolds, and MAC Performance makes a matching high-flow y-pipe for them.

 

Id go all new. That's what I did cuz lets just say the guy I bought my 86' 305 from was a hack welder. 286 bucks and I have new headers and complete 3" all the way back.

 

Well I'm thinking that I'm going to wait until my little cast adapter thingy comes from the guy on ebay. If that's a no go with my stock Y pipe and manifolds, I'll buy this: http://www.hawksthirdgenparts.com/pr...des-YPipe.html

and have it plumbed into the catback that's already on there. I'll get either a test pipe for the time being, or get a high flow cat. Either way, at some point, I'll be getting headers ... I have a 383 stroker I have to think about as well. There's absolutely no way that engine will get stock manifolds on it ... I just need this car to run so I can drive it for a while so I can have enough space to build the 383. And I have some body work that needs to get done before she gets a 383

 

Incomplete list by at least 1 combo not listed (mine).....1987 single cat L98 (but I see no 1987 listing, not just for a single cat version).

 

Well that part I got on ebay is the wrong one .. so it's either the headers or the exhaust shop for me. I would much rather fix this myself ... is there any way to tell if a replacement Y pipe would fit without me just ordering one and finding out?

 

Just getting a pair of shorty headers and matching Y-pipe, it'd be much easier and the power gain is an added bonus. If you want I could point you to some header and y-pipe combos.

 

Well I've basically made up my mind about the headman 68470 with matching Y pipe 47179:
http://www.jegs.com/i/Hedman/500/68470/10002/-1
http://www.jegs.com/i/Hedman/500/17478/10002/-1

My question is, what size header bolts do I need? I'm thinking of getting these: http://www.jegs.com/i/ARP/070/400-1101/10002/-1 which I think is the right size/pitch, but is 3/4" length long enough? No adapter plates, stock headman flanges ... I'm thinkin' 3/4 will be fine. But I've been counting and it looks like I'll need 16ish bolts instead of the 12 that come in that pack.

Also looks like the jegs version of these headers doesn't use the ball/socket flange design like Summit does ... what gives? Is there a difference between the jegs/summit versions? I suppose I can order from summit ... it's just I've ordered from jegs before and don't have to setup an account

 

Well I just ordered myself a set of Headman 68470 headers and 17478 Y pipe. This will undoubtedly solve my exhaust issues. I'll have to bypass my cat for now, but it's a great opportunity to get a nice high flow cat. It will all be clamped exhaust pieces. I don't have a welder to weld up this exhaust good n' proper, but it'll work for the time being.

Thanks everybody for all their input! I can post pictures of my install if anybody is interested. I'm planning on doing the engine tilt method to get the passenger side header on, so we'll see how that goes. The car's currently setting nice and high on jack stands, so it will be easy to take pictures if anyone is interested.

 

Well my manifolds, gaskets and attaching hardware is posted on Ebay for those interested.
http://www.ebay.com/itm/200791781260...#ht_500wt_1156

Again, thanks everyone for the help. I am very glad I ordered headers ... these headman headers are really nice.

 

Well to anyone interested in the headers I've mentioned before, the 68470, there is NO 02 sensor bung ... so I did this:


7/8" bimetalic hole saw, 1/2" cordless drill, a little oil and it cut through with no problem. I just made sure the sensor was pointing toward the rear of the car for clearance concerns.

 

https://www.thirdgen.org/forums/afte...s-headers.html

 

That's not even nice ... My headman's definitely fail to provide the awe factor that dyno Don's do, but they function as an exhaust containment vessel. I only just last week started my engine for the first time since its rebuild. It'll burn rubber really easily in my garage, but I'm pretty sure it could have done that before I put headers on it.

Budget was my main concern. I needed manifold replacements that had a matching Y pipe to them. So far, my exhaust is leak free, very quiet, and my muffler (I think it's an OEM grade aftermarket muffler) sounds great. Quiet at idle, but really has a nice tone and volume when you get into the throttle.

I'll pick me up a pair of Dyno Don's headers when I get a bigger engine ... (Like the 383 I have waiting for me to build it)

 

For anyone that might be having the same issue of connecting a y-pipe such as Magnaflow to stock TPI exhaust manifolds, I picked up an exhaust flange gasket at Autozone today that looks to fit perfectly. It's from Walker, p/n 31533. The inner diameter aligns perfectly with the TPI passenger side manifold. Be advised though, it is only a little thicker than a half inch or so. It is not the same thickness as the original spacer.