Headers or iron manifolds?

[GoToGuy]

Nope, the OBD 1, trucks have one O2 sensor. It's mounted just ahead ( in front ) of cat converter.

 

[Schurkey]

Nope, the OBD 1, trucks have one O2 sensor. It's mounted just ahead ( in front ) of cat converter.

Often in the left exhaust manifold.

 

[LVJJJ]

Hello.
I am working on an 88, 4wd, 3/4 ton pickup.
It will be street driven and I plan on doing some towing and hauling.
Stock 350 is getting a mild cam, early 70's heads (1.94 x 1.50), 600 cfm carb, edelbrock performer intake, hei dist.
I am not looking to squeeze every ounce of power, but I don't want to cork this thing up, either...
I contemplated shorty headers, but it looks like I would never see my spark plugs again.
Are they that bad?
Are there cast iron manifolds that would do me better than the factory TBI units, power-wise?
I would like to run dual exhaust if possible, unless an aftermarket y-pipe could give similar results.

Thanks.

Looks like there have been many posts on this subject, but I don't have time to read them all so this response may be redundant, but I think its relevant. I installed JBA shorty headers some time ago, mainly because I kept cracking the iron ones. I was told I was doing that because I was revving to 3700+ rpm in 2nd to pull travel trailer up all the mountain passes we have here in Washington. This was with the original 350 engine and I was not going to slow down. After the third one I reasearched headers and settled on the JBA headers. Perfect choice. Main thing is that I don't crack them. They have added more power, not a lot but enough to be noticeable. They fit perfect at head and with stock exhaust pipe. I found some perfect gaskets too, Remflex. They seal great and you don't have to go back and retighten. Now the headers are on my 383, still working great. The 383 has so much torque that I can go up the passes in third instead of 2nd at high rpms. Because of heat generated by headers, I remove the splash guards behind the front tires in the summer as there is really no other ram air coming into the engine compartment from the front. Put them back on in the rainy winter. Oh, and I've been running dual exhaust for years.

 

[L31MaxExpress]

Looks like there have been many posts on this subject, but I don't have time to read them all so this response may be redundant, but I think its relevant. I installed JBA shorty headers some time ago, mainly because I kept cracking the iron ones. I was told I was doing that because I was revving to 3700+ rpm in 2nd to pull travel trailer up all the mountain passes we have here in Washington. This was with the original 350 engine and I was not going to slow down. After the third one I reasearched headers and settled on the JBA headers. Perfect choice. Main thing is that I don't crack them. They have added more power, not a lot but enough to be noticeable. They fit perfect at head and with stock exhaust pipe. I found some perfect gaskets too, Remflex. They seal great and you don't have to go back and retighten. Now the headers are on my 383, still working great. The 383 has so much torque that I can go up the passes in third instead of 2nd at high rpms. Because of heat generated by headers, I remove the splash guards behind the front tires in the summer as there is really no other ram air coming into the engine compartment from the front. Put them back on in the rainy winter. Oh, and I've been running dual exhaust for years.

That is not why you were cracking manifolds. The stock ones are just crack prone. Both manifolds on my Vortec were cracked at something like 65K miles. I put Summit branded shorties on the van first. There was a definite power gain but my van also had OE dual 3" pipes off the manifolds. I think the stock exhaust pipe size off the manifolds is why some feel shorties suck and others believe that exhaust changes alone with stock manifolds work just as well. Few people make both changes. Properly sized long tubes will always make the most torque as they offer the most scavenging. I personally like 1-5/8" primaries and a 2.5" collector into a 2.5" pipe for most small blocks. 3" collectors really do not hurt anything either.

My 383 will pull some grades in 4th and only downshift to 3rd on some steeper stuff. I feel at lower altitudes if I had a little more gear in the rear-end (even a 4.10 gear) it would probably pull most grades in 4th. With the 1-ton LT sized tires my 3.73 gears are an exact match gearing wise to the way my van was with 3.42s and the P-metric tires on the 1/2 ton. Switching to a 4.10 gear would put me gearing wise the same as the 3.73 9.5" I ran with the 1/2 ton suspension and shorter tires back when I had the 350.

 

[GoToGuy]

Often in the left exhaust manifold.

Okay, I'm guilty of looking at a Calif emissions trucks, are not an representative of all 50 state build trucks. ( Tunnel vision?) As that's all I see. I stand corrected, and will sin no more.

 

[someotherguy]

Often in the left exhaust manifold.

Non-heated, absolutely. On the heated O2 trucks (my old 1994 for example) it's just ahead of the cat.

Not that those are the definitive arrangements, example: my former '95 3500HD 7.4/NV4500, non-heated O2, down in the pipe to the muffler - which was ahead of the cat, big pellet style. Factory exhaust. Weird arrangement.

Richard

 

[L31MaxExpress]

Non-heated, absolutely. On the heated O2 trucks (my old 1994 for example) it's just ahead of the cat.

Not that those are the definitive arrangements, example: my former '95 3500HD 7.4/NV4500, non-heated O2, down in the pipe to the muffler - which was ahead of the cat, big pellet style. Factory exhaust. Weird arrangement.

Richard

I have seen small blocks setup that way too. Single wire right ahead of the cat. Only really noticed that placement in the HD emissions trucks and many of them open loop idle.

 

[93chevyluvr]

Potentially found some but I will still need to extract the broken bolts.

You must be registered for see images attach

 

[SUBURBAN5]

I have no firsthand experience with the new Holley/Hooker cast iron exhaust manifolds,
but they are getting good reviews, are supposed to flow better than stock,
you can still get to the plugs, and they have nice lines/easy on the eyes:

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Me? If I can't have a set of no-nonsense long-tube Tri-Y headers connected
to a quiet(er) high flow exhaust, I'll skip the shorties and go right for these
new performance-oriented cast iron manifolds. (I'll take the titanium-colored
ceramic coating - see attached.)

EDIT: I may have been misled elsewhere. The attached photos may be natural,
but I'd want the ceramic coating for rust free long-term + less heat radiated into
the engine bay. So I'll take the black ceramic over the natural.)

I'm too old to put myself through the header aggravation if they aren't going
to deliver enough additional performance to outweigh the extra effort.
Especially when using a stock/near stock cam where the difference between
a higher flowing cast iron exhaust vs. a shorty header just won't be there.

I like to add something I just learned today.
For anybody reading this in the future. This manifold from hooker is the closest quality to stock. There missing the egr return, which requires a block off plate and tuning...
These pictures I uploaded are from a sales brochure of a 98 suburban. It provides what the stock manifolds are made of.
The screen shot is what hooker is made of. So anybody not looking for headers and want to go the stock manifold route keep this in mind. Dorman, and other non names from rock auto don't advertise what there made of. So imo that's why there crap and keep cracking. It's so hard to find a good quality manifold, that it's almost better off buying headers.. but for anybody insisting on manifolds then do your homework and find high silicon molybdenum cast nodular iron!

 

[HotWheelsBurban]

I'll have to get under Rawhide and see what the exhaust manifold outlets and downpipes measure out. I have heard that the one tons got bigger exhaust, and maybe the 8 lug 2500s did too. I think everything forward of the mufflers is stock and original. It looks bigger than what's on the Burb, anyway....