exhaust pipe size and routing opinions?

[samwise68]

i'm getting ready to buy pipe for my exhaust. it'll be on a stock 307, aside from headers. i already purchased glasspacks to use, however they're 2" in/out. (i hope that won't be a problem.)

so, i'm wondering how you might reccommend i stage down the exhaust pipe from collectors to the tail pipe? how about tips?

and how you personally would run your home brew exhaust pipe?

i appreciate any and all input...thanks in advance!

-Sam.

[EAST SIDE LOW LIFE]

Originally Posted by samwise68

i'm getting ready to buy pipe for my exhaust. it'll be on a stock 307, aside from headers. i already purchased glasspacks to use, however they're 2" in/out. (i hope that won't be a problem.)

so, i'm wondering how you might reccommend i stage down the exhaust pipe from collectors to the tail pipe? how about tips?

and how you personally would run your home brew exhaust pipe?

i appreciate any and all input...thanks in advance!

-Sam.

**********************************************************

This is a handy little tool. This is a 2 ft. ruler that is very flexable. I do not know what length of header you are installing but this will allow you to go from the collector and make your bends, take the ruler trace it on flat cardboard, measure the width of pipe on the cardboard in this case 2' and draw the same form again using the ruler. Cut out and now you have a template to go to the exhaust shop with and get your pipe bent. Do the same for the diff. etc. The lengths of straight pipe use a regular tape measure and order your 2' lengths.

esll.

[jc1969c10]

So where did you find this flexible ruler. One of my next projects for my truck is headers and exhaust.

[samwise68]

oooo. good idea!

Thanks ESLL.

i will definitely use that when i get the rough outline ready for the routing. i had an idea to use a length of indoor electrical wire, since it's long and flexy-like. but i like that idea better. it's much more...precise.

oh, btw, i love your GMC. . it's one of my favorites on here.

would running dual 2" pipe the whole length, be an issue, in your opinion? or any one elses for that matter. i'm kinda concerned about strangling the little thing. however, stock for it was a 2.25", or 2.5" single pipe, if i'm not mistaken?

idk.

any input welcome!

-Sam.

[EAST SIDE LOW LIFE]

[QUOTE=samwise68;2354287]oooo. good idea!

Thanks ESLL.

i will definitely use that when i get the rough outline ready for the routing. i had an idea to use a length of indoor electrical wire, since it's long and flexy-like. but i like that idea better. it's much more...precise.

oh, btw, i love your GMC. . it's one of my favorites on here.

would running dual 2" pipe the whole length, be an issue, in your opinion? or any one elses for that matter. i'm kinda concerned about strangling the little thing. however, stock for it was a 2.25", or 2.5" single pipe, if i'm not mistaken?

idk.

**********************************************************

The pipe size I run is 2.5' with 4' s/s tips. Is there a reason you want to run 2'? The cost of pipe is not much difference.

I just was in touch ECE and my headers are in today so they will be shipped out tomorrow and when they arrive in about a week I'll be doing a post on bending pipe and installing these headers. The headers are 3/4 Sanderson Headers made for our 67/72 trucks.

esll.

PS: Thanks for the kind words ....

[EAST SIDE LOW LIFE]

Originally Posted by jc1969c10

So where did you find this flexible ruler. One of my next projects for my truck is headers and exhaust.

**********************************************************

I borrowed it from a buddy of mine. He's coming over tomorrow and I will ask him and post you.

esll.

[samwise68]

the only reason i bought the 2 inch is my dad recommended it. he said that it'd be easier to work with the 2 inch, and it probably wouldn't have any negative effects on the engine breathing, etc.

idk. should i find my receipts and go back to the store?

any advice would be great. thanks!

-Sam.

[EAST SIDE LOW LIFE]

I would but that is just me. A 2.5' will be able to breath better without any back pressure problems. Your dad will probably not even notice it. I think you would be happier and when the exhaust police (fellow experts) ask and they will .... Why did you go 2' and you say because my dad suggested it. Not cool if you know what I mean. Now if he suggested 2.5' or 3.0' ....

esll.

PS: 2.5' can be made to look fatter with a 3' or 4' s/s tip. Remember most of these tips fit 2.5 and up.

[Spray-Bomb]

I ran 3" & my dad says I have way too big of exhaust, but IDK it sound sweet

Just remember: bigger = deeper & smaller = higher pitch

I prolly do have too big of exhaust for my engine, but I like it anyway

[OhioDan]

Running ramhorn exhaust and the muffler guy sized it up to 2.5" after the manifolds. Here's a pic. It runs under the center crossmember and back along either side of the gas tank.

[BCOWANWHEELS]

2 inch is perfect for duals and a stock 307

[samwise68]

thanks for all the input guys.

the build on this truck is very limited - headers to breath, and thats it. so, i think 2" will be fine.

and, i know it's kinda lame going by what my dad says, but, he's kind of my guide lines on this build - as in, my co-builder, i suppose. and, i'm going to stick with his word. it'll keep peace. and it's not like he doesn't know what he's talking about. he's only been a mechanic for around 35 years, give or take a decade.

and thats all in prelude to me not being able to find the receipt to take them back. :P. so, i'm not going to worry about it.

it might be kinda high pitched. but, thats ok. if i don't like it, i can always change it.

with that being said, there comes the question of straight 2 inch after the collector/reducer? or stage it some how? idk. thoughts on that would be appreciated as well.

thanks again guys!

-Sam.

[KFreddy]

Originally Posted by BCOWANWHEELS

2 inch is perfect for duals and a stock 307

I concur 2 inch is perfect for duals, 2.25" or more so 2.5" would kill your low end...

[samwise68]

Originally Posted by KFreddy

I concur 2 inch is perfect for duals, 2.25" or more so 2.5" would kill your low end...

haha, thats great to hear!

i was afraid of that. and with 3.07 gears, i'm gonna need all the low end i can get. thanks for the input!

-Sam.

[BCOWANWHEELS]

you,ve got to have the proper amount of back pressure. i,am 53 yrs old and still remember the real LT1 ENGINES. 2 1/4" duals made them run perfect any bigger and it would slow em down same with smaller. a 307 with 2" duals you,ll be very happy with the outcome. i might also suggest switching to a hei ignition and a good breather setup. you should be in the hi 15,s or better mpg . cadilac mufflers are what we used to run . cherry boms hurt performance unless you have great gas and lots of compression.
bob

[EAST SIDE LOW LIFE]

Originally Posted by samwise68

thanks for all the input guys.

the build on this truck is very limited - headers to breath, and thats it. so, i think 2" will be fine.

and, i know it's kinda lame going by what my dad says, but, he's kind of my guide lines on this build - as in, my co-builder, i suppose. and, i'm going to stick with his word. it'll keep peace. and it's not like he doesn't know what he's talking about. he's only been a mechanic for around 35 years, give or take a decade.

and thats all in prelude to me not being able to find the receipt to take them back. :P. so, i'm not going to worry about it.

it might be kinda high pitched. but, thats ok. if i don't like it, i can always change it.

with that being said, there comes the question of straight 2 inch after the collector/reducer? or stage it some how? idk. thoughts on that would be appreciated as well.

thanks again guys!

-Sam.

**********************************************************

Well I stuck my foot in it this time! I never connected with your engine being a 307 I thought it was a 350. As far as your dad and you doing a project together this is cool, NO DISRESPECT intended so in my opinion it's not lame to take his advice. If I offended anyone I'm sorry.

esll.

[pitt]

i dont know how your emission laws are but they really dont care too much here so i just said forget the full exhaust...2.5 in pipe off of flowtech full length headers and glass packs. cheep effective and sounds mean as he!!

[samwise68]

lol, no worries ESLL.
i appreciate all the feedback i can get. if i didn't want it, i wouldn't have asked for it. thanks again! i'll definitely be lookin for a flexy ruler and/or something close to that for routing.

BCOWAN - i plan on adding HEI, along with a fuel pressure regulator, vaccuum gauge, etc. i'm kind of mimicking the build my dad had on his '68 C20 when he was in his 20's. hense the kind of "out dated", if you will, antics. i have an old truck, so why not have an old guy help. thanks again for your input!

-Sam.

[samwise68]

Pitt - emissions are null in my parts, so that was never really an issue. i just don't want the dronning of exhaust exiting under the cab, or anything like that. it can get annoying on long trips. so, i'm hoping to avoid that.

....maybe. haha

-Sam.

[Dick Dale]

pitt has a good system if your already deaf and the floor has no holes. I had one like that on mine and driving was unpleasent to say the least.

[pitt]

hell i love it ... scares the hell of the children hehe...and im already deaf from artillery! nope no holes in my floor either... the rockers dont count.

[72BLUZ]

My Exhaust Is Similar To Ohiodans. The Diff Is I Had My Cross Member Cut With A Plasma Cutter And My Pipes Ran Thru It. Thus Keeping The Pipes Hid

[Robznob11]

well my opinion, 2 in is perfect for a 307 as stated more size would only hurt you, i prefer turbo style mufflers but if you already got glass packs oh well, on key thing i did not see mentioned or maby i missed while reading, do not for get to put a cross over after the headers i like X better than H but H is better than not one at all if your on a budget.

[Spray-Bomb]

Originally Posted by pitt

hell i love it ... scares the hell of the children hehe...and im already deaf from artillery! nope no holes in my floor either... the rockers dont count.

I'm the same, minus the being deaf & rocker rust