Manifolds on a 80s 350

[mattpiotr]

I got headers on my 86 gmc 4x4 2500 its got a strong 350 it has true duals with original 40s im starting to get a headache from the gaskets and collectors and flange and spark plug wires getting burnt and i cant run the plugs that i want. i want to switch to ram horn manifolds but before i do i want to find out some more on them? first off how are they? is their anything i should look for if i buy a used set? is their a cretin set i need for the 4 wheel drive? should i go with 2" or 2 1/2"? what are the good styles? and will it make my exhaust sound different? and anything things Thanks i found a set on summit but cant justify spending $299.99 for these http://www.summitracing.com/parts/AAF-ALL34200/

[motornut]

watch for the stud holes rusting out
i had a log set from my 78 4X2 burb now on the 79 4X2 jimmy
i read that grinding out the nibs helps flow/sound better,and also a cross over H pipe

[mattpiotr]

Originally Posted by motornut

watch for the stud holes rusting out
i had a log set from my 78 4X2 burb now on the 79 4X2 jimmy
i read that grinding out the nibs helps flow/sound better,and also a cross over H pipe

nibs?

[bilfman]

Personally I would stick with headers. I have ran headers on every v8 I have owned. That is many over the past 24 years. There are some big differences between headers and cast manifolds. But the pay off is worth it. Headers flow better and make more power, hands down.

Keeping that in mind manifolds tend to be a zero maintenance item (that is why automakers put them on), headers on the other hand are a maintenance item. It is not huge maintenance but it is really worth it. Firstly use good gaskets, re-torque every drive for the first 4-5 drives after a fresh install. After that check them every month or so.

As to burnt wires, there are many boot/wire designs that can get you through this. My fav's are MSD Streetfire 8.0mm straigtboot, these are great because the boot is bendable. This enables you to miss any header contact.

Cheap headers are ok. But it is worth the extra to go to a more expensive set, thicker flanges and slightly better tuning and bends make a difference.

That said, my love of horsepower, growl, mileage far outweighs the little extra wrenching that comes from header ownership. When done right, fit , leaks and burning are a non issue.

And definitely go 2 1/2.

[mattpiotr]

Originally Posted by bilfman

Personally I would stick with headers. I have ran headers on every v8 I have owned. That is many over the past 24 years. There are some big differences between headers and cast manifolds. But the pay off is worth it. Headers flow better and make more power, hands down.

Keeping that in mind manifolds tend to be a zero maintenance item (that is why automakers put them on), headers on the other hand are a maintenance item. It is not huge maintenance but it is really worth it. Firstly use good gaskets, re-torque every drive for the first 4-5 drives after a fresh install. After that check them every month or so.

As to burnt wires, there are many boot/wire designs that can get you through this. My fav's are MSD Streetfire 8.0mm straigtboot, these are great because the boot is bendable. This enables you to miss any header contact.

Cheap headers are ok. But it is worth the extra to go to a more expensive set, thicker flanges and slightly better tuning and bends make a difference.

That said, my love of horsepower, growl, mileage far outweighs the little extra wrenching that comes from header ownership. When done right, fit , leaks and burning are a non issue.

And definitely go 2 1/2.

im looking for more of maintance free, the truck is a daily driver, it it was a sunday driver then i would for sure but headers on it but im thinking ram horn manifolds 2 1/2"

[motornut]

I don't know about the "rams" having these nibs and casting marks
over the years I've seen these get ground out and smooth out the casting marks for better "undisturbed" flow when using the manifolds
My 78 came with them
both 79s too
I like headers too,but keeping this 79 more stock look

[motornut]

every little bit helps right !
took maybe 3 hours...
and it didn't make it any quieter

[mattpiotr]

Originally Posted by motornut

every little bit helps right !
took maybe 3 hours...
and it didn't make it any quieter

Not Bad, How Do you like the sound? i got headers on it now and im afraid of switching to ram horns or stock manifolds and loosing the sound

[mattpiotr]

Well believe it or not i picked up a set of corvette 2 1/2" Exhaust Manifolds in really good shape for $30 per side, i thought it was a steel for that, i have to get part of my exhaust redone so the manifolds will work, i have headers on the truck down with true dual no cats original flowmaster 40s stright out the back to 6" tips i really love the paddle rumble i get when i get on it but when you let off the gas it is kind of a mixture of a rumble and a few pings, would a h-p help with the rumble? and will it make my exhaust quite?

[mattpiotr]

Flowtech Headers, that leak would never buy flowtechs, no cats and original flowmaster 40s back to chrome tips, 1986 GMC 2500 with 350 v8, edelbrock intake and 600 carb fresh rebuild going to take headers off and go with corvette manifolds hope i dont loose this sound

[motornut]

sounds great

[bowtiemanchevyman]

If you go with the manifolds you will lose horse power. the headers are so much better. the gasket problem is if you use cheap gaskets it will leak. i use the manifold gaskets on the head flang and i use the cooper ones on the collecter. the wires you need to buy the one you make your self and buy a good set of wire looms i use PRO-141-638 and i never had a wire burn yet. you have to run them the right way so they new do.

[3r!c84]

junkyard man just get a set of sbc manifolds . shoot i got mine laying in the garage on the floor lol

[INSIDIOUS '86]

Your going to lose sound with exhaust logs no matter what
Posted via Mobile Device

[mattpiotr]

Originally Posted by INSIDIOUS '86

Your going to lose sound with exhaust logs no matter what
Posted via Mobile Device

even with the corvette 2 1/2 ram horn manifolds?

[mattpiotr]

Originally Posted by bowtiemanchevyman

If you go with the manifolds you will lose horse power. the headers are so much better. the gasket problem is if you use cheap gaskets it will leak. i use the manifold gaskets on the head flang and i use the cooper ones on the collecter. the wires you need to buy the one you make your self and buy a good set of wire looms i use PRO-141-638 and i never had a wire burn yet. you have to run them the right way so they new do.

its not the wire its self that gets burnt its the end of it that plugs into the plug their is no room between the tube and the wire cap. i had a boot on it but it burnt thru the boot and thats even with wire looms.

[mattpiotr]

Flow Tech Headers keep burning wires, is their different style long tube headers? 86 gmc 2500 4x4 350 sbc.

[88Jimmy4x4]

I looked into the ram horns from summit but I wasnt sure how it would work coming straight down. I think the factory truck rams swept back about 30deg

I bought a set of these accel ceramic plug wires but they are pricey, summit and jegs both sell them

http://www.trucktrend.com/features/g...ets/index.html

[motornut]

Originally Posted by 88Jimmy4x4

I looked into the ram horns from summit but I wasnt sure how it would work coming straight down. I think the factory truck rams swept back about 30deg

I bought a set of these accel ceramic plug wires but they are pricey, summit and jegs both sell them

http://www.trucktrend.com/features/g...ets/index.html

theres some serious heat protection.

[manimal]

rams horns will still sound good, but wont be as loud as headers.

[donut]

Don't know which thread to post in, so I'll go with this one.

Get a plug wire with normal size boot. The pic 88Jimmy4x4 is a normal size boot. (IMO, the ones you have are huge)
Ding the header to get clearance. (I've had to do this on every cheap set of headers I've owned, never tried the expensive ones.)
Possibly get a "shorty" spark plug.

Whatever it takes, get clearance. If it's touching, it will get burnt.

[Shane22696]

Get a torch and a hammer, and dimple that tube. Works like a charm

[donut]

It may quite it down a little.
Now that your re-doing your exhaust, where in 2 other threads on this page your worried about burnt wires and your headers, talk to the muffler shop that's doing the work.

[Firebirdjones]

H-pipe is definately worth adding. If you can swing an X-pipe in there they work even better.

Either one will tend to quiet the exhaust to a point (takes the slappyness out of it in most cases) but the real benefit is a little more power through the mid range. Won't feel it in the seat of your pants but I've seen 3-5 HP/TQ differences on the dyno.

[powerdriver 1958]

XIV. Multiple Posting - It is simply not acceptable to post your question more than once, or to post it in more than one forum. Choose the forum that your question or post best fits in, and place it there and only there. If, after posting, you feel it should be in another forum, private message the forum Moderator and ask if they would move it for you.

All 4 exhaust posts are now merged into one , Merging tends to make a mess .