Customs Question on Glasspack Length

Hello,
I'm looking for glasspacks for my 53 Chevy but I want a particular sound. I have a small block 350 with straightpipes. I measured 2" diameter pipes but the last 3 feet is tapered down to 1.5" diameter with pencil tips at the end.

I have attached a youtube video of the sound I am going for as well as what mind sounds like right now.



Brockman suggested 17" or 22" Mellowtone but didn't really know which of the two would be better. They said 17" would be louder but 22" quieter. I want something that doesn't sound too loud at idle, but barks when I step on the pedal. Does anyone have advice? I am leaning towards 17" but am not sure if 22" would be better.

 

If that's the sound you want (loud), then get the 18" steel-packed Brockmans. I have them on my '61 and I love them!

 

Really loud and raspy exhaust gets old in a hurry. If it were my car I'd go with the 22" x 2" Mellowtones and open up the rear part of your pipes to 2" diameter. You can then install 2 1/4" or 2 1/2" exhaust tips on the ends of the pipes to act as "echo cans". This will give you a very deep sound, not the raspy tones you have now. Be sure to position the ends of the echo cans just inside your rear bumper to keep from squashing them when negotiating driveways. Sounds better that way, too.

You can "cheat" just a little bit by installing the mufflers backwards, so that the internal louvers open to the rear instead of to the front. This will give a little bit more "edge" to the exhaust note while not substantially increasing the noise level.

 

^^^ On that note, 53CHKustom, if you do your own install, here's a tip. Attach your mufflers to your system with those stainless band clamps. That way, if you want to change to say, a quieter muffler, it's much easier to swap them out.

 

Thanks, any idea what it would sound like with 22" and the 1.5" pipes now? I don't mind the raspy sound when I step on the pedal but want a lower sounding rumble when not on the gas. I'm not sure if the 17" is a bad idea based on that?

 

the shorter the glasspacs the rattier they sound. The longer they are the deeper and more rumble. ratty gets old pretty quick.

 

Thanks that is useful advice.

Will I gain anything going with 22" glasspacks over just leaving the straight pipes alone? I want that extra rap/bite when I step on the gas pedal and let off it. I love the way it sounds in the video clip right when they lay off the pedal, but definitely prefer a lower rumble sound on idle.

 

2" into 17" glasspacks located early in the system followed by 2 1/4" out from there. thats the way i've set up a bunch of stuff. fairly mellow at low rpm's but rappy when you get on it. don't get wrapped up to much in brand names. brockmans are nice but if i'm going through the effort of ordering brockmans it's probably gonna be steel packs. smithy's are probably lower list sound wise. i know i'll probably get shamed for that statement but just my opinion. my favorites are purple hornies probably. cherry bombs aren't bad and you can find them in stock in just about any parts place in the us.

 

I went ahead and ordered 22" Brockman glasspacks. I guess I am still wondering if I will see much or any difference when I install the Brockmans onto the 1.5" straight pipes over just leaving the straight pipes as they are. Does anyone know?

 

you said it's just the last 3 feet drop down to 1.5" replace that with 2". i'm sure they dropped pipe size to add in restriction/backpressure. putting the glasspacks in is going to do that also possibly making it to restrictive. so i'd deffinetly get rid of the 1.5 and at least put 2" in it's place maybe even look at just re doing everything behind the glasspacks with either 2, 2 1/4, or 2 1/2.

if what is 1.5" is behind the axle it would be easy and shouldn't cost to much. finding a GOOD exhaust guy now isn't as easy as it once was. i lost my awesome on when i moved from east carolina to west carolina and honestly thaught i may have to rig temp systems on stuff i was picky about and drive 5 hrs. But with an afternoon of riding around and talking to several in the area i found a local thats as good or better than my eastern guy. as it turns out his prices are also the most reasonable of all the local shops. not quite as cheap as my east side guy but 5 minutes away instead of 5hrs is much better. so don't be affraid to spend a coupla hours stopping by and talking to a few different shops about what you want. you may run into a deal like my old guy. he did the "fun jobs" after closing. $200 and a case of beer, and you supply whatever mufflers you wanted to use got a full front to back true dual set up...

 

Hi everyone.
I've continued to ask people for opinions. One exhaust shop said I should go with 26" mufflers with a 2 1/2" core and run larger diameter pipes for the performance sake but they quoted me $600 for this job.

Brockman says to try the 22" mellowtone glasspacks as is, and if the car is sluggish I should replace the last 3ft with 2" diameter pipes. I have 2" pipes except 1.75" the last 3ft that go into pencil tips.

I'm tempted to just go with the mellowtones I already ordered since a friend of mine who has a welder said he can install them for me. I've noticed my 53 is a little sluggish up steeper hills in our region so I'm not sure if I should even waste a 22" glasspack set and up with a sluggish car. Any more advice given I already ordered them? I'm not sure if 2" pipes all the way and the glasspacks with pencil tips at the end should be just fine? I don't want to spend too much on this project right now.

 

where in the system does it drop down to 1.75? In front of or behind the rear axle?

if it's behind the axle it's easy to do yourself. even if it's before the axle you can buy premade bends and do it yourself but unless you have a lift i would weld as much of it together outside of the car and route it in for the last connections so you're not under the car welding overhead as much.

I don't know where you're located(tried to look but either it's not listed or it's just other new hamb feature i don't get). but around here $600 is kinda the higher end price wise esp if you're supplying the mufflers.

unless your state doesn't allow it you could also exit them in front of the rear wheels for now. you can pick up everything you need to do that at any local parts house for probably $50-100...ken...

 

Thanks so much! I am located in Southern CA and the shop that quoted me has experience with exhaust for 50s customs and muscle cars so maybe they are pricey because of their expertise.

It drops down to 1.75" pretty much rear of the axle if I remember correctly. I'm guessing the glasspacks should be installed closer to the transmission, making the conversion to 2" on the last 3ft a separate operation.

 

i tend to put them early in the system usually right under your front floor or so, so yes 2 seperate operations. if you told Brockman you have 2" outer diameter pipe the unit they send you should have ends slightly larger(2 1/8" if memory serves) and the pipe slips right into the inlet/outlet and you weld or clamp it in place. easy peasy.........

for the pipes where it steps down behind the axle(if that is so) cut them off at the step down and replace with 2, 2 1/8, 2 1/4, or you may find 2 1/2 with collars/steps that lets it match right up to the 2" thats there already. there are adapters/joiners that can do this if you can't find pipe made to slide over.

it doesn't need to be somebody that knows 50s/60s hot rods/customs. the best exhaust guy i ever had could run whatever you want and he was just a small town muffler shop. stay away from the chain shops find a little muffler shop on a side street that looks like a WELL USED shop.

 

Thanks. I looked underneath this morning and it seems the 1.75" diameter is ahead of the axle. The pipe does not bend at all to hug the axle closer. They do bend in the horizontal plane so they are spaced farther apart from each other when they exit the bumper.

I found something worrying me a little. One side of the pipe kind of below the front seat is more square looking in shape for about 12 to 16 inches. It's not fully pinched tight though. Perhaps the previous owner ran over something. It rides rather low with dropped spindles in the front and air bags in the rear.

I'm wondering if all the pipes need to be redone. If so, should I not use the 22" brockman glasspack and go with a 26" 2 1/2 core muffler/glasspack so I have a more responsive car going up steeper hills (I don't plan to drive the car fast in general)?

 

The size of the exhaust pipe is not doing to make much difference in engine torque at lower rpm. If fact a larger diameter pipe might hurt it. Exhaust size doesn't become a big issue until you get into higher rpm's, which I drought you encounter in normal driving up and down hills. If you have a lack of low rpm power from a 350 I would start looking elsewhere. What is the rearend gearing? Carburation? What type of exhaust headers? Etc. 2 inch dual exhaust is plenty large enough for low rpm non-performance driving. If you are hot rodding it and adding high performance equipment, headers and so on, then you might consider a larger exhaust system.

One fairly easy addition that will help is adding an H/X pipe. Again, what type of exhaust headers are you running? An H or X pipe as close as possible to the exhaust headers can make a big improvement in performance.

 

Closer the muffler is to the exhaust manifold and longer the pipes, the raspier it will sound. Mufflers positioned closer to the rear sound much more mellow.

 

Thanks! I'm not super knowledgeable on exhaust. I've had the car since late last year and bought it from someone locally who had done the work to it. I have attached a photo I have saved on my pc at work in case it helps determine. I'm not interested in high performance, it's just a cruiser but I do have some steep hills to go up so I was concerned the current exhaust setup could cause it to become more sluggish uphill.

I'm not sure on the rearend gearing but it supposedly has a rearend from a 57 chevy.

 

Why not go with the straight 2" exhaust and 22 muffler and install a pair of electric exhaust cutouts that you can open with a switch when you want it loud?

 

go with glasspacks around 20" or a little longer, pips no smaller than 2". you can even go 2.5"..big blocks have a deeper sound than small blocks I've found, and I love the sound of straight pipes on those. but the shorter the glasspack and narrower the pipe it will be higher pitched a rapp a lot.

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Thanks! I was thinking of installing the 22" Mellowtone Glasspacks and 2" pipes with pencil tips at the end but wasn't sure if I'd have a sluggish car. Some friend's I've asked tell me to go with larger diameter pipes, etc. I don't need high performance, but I want to avoid making my car more sluggish since I have hills to go up. It seems like that won't be the case according to the responses on this thread.

 

I would check the gearing as far as hill climbing goes. There is always a trade-off between mileage and pulling power with rear end gears. Do you know how to check you rear axle ratio? A fairly simple method is to find some level ground, put the car in neutral and mark a line on a rear tire, then mark the drive shaft. Have someone count the number of turns of the driveshaft while you push the car through one full revolution of the tire. Should be somewhere between 2 to 4 driveshaft revolutions to one tire revolution. Then you need to guess at the difference between the position of the driveshaft mark and it's original position. Say the driveshaft turned three times and the mark ends up say a quarter revolution past the starting position. That would be around a 3:25 rear end. Say it was just short of 4 turns by a say 10 % of a revolution, that would be 4 - .10 = 3:90 rear end. Sounds a lot more complicated that it is, really simple and quick. This will give you a ballpark range for the rear end gear. Different manufactures use different common ratios so it is fairly easy to guess what gears are in a given rear end.

 

As far as the exhaust goes, go for what gives you the sound you want. The size of the tubing and the length of the muffler are going to have almost no impact on the performance in your application.

 

if the tube thats there is "crushed" damned near closed that may be where your problem is as it's restricting flow. if it's just been ovaled a bit then thats probably not an issue. hard to impossible to say without seeing it. if the tube is good a foot or two behind where the firewall/toe board/floor meet you're in good shape as thats where you want to "patch in" the glass packs. after that you can either keep it easy and dump them out in front of the rear wheels. all you'd need to do is put a 45 degree turn in the pipe at the right spot and have it dump where you chooose. the legalities on this vary from state to state and how tightly it's enforced.

or you can have a shop redo the pipes from behind the glasspacks out running it over the rear axle. thats probably something best left to someone who knows more about routing exhaust than you do(no offense).

if the tube is crushed/pinched further forward than where i'm suggesting the glasspacks go it's probably because they weren't tucked up very well. i've see some pretty horribly run pipes hanging well below the frame/rocker level. NOT what you want on a low car.

 

Thanks! The shape of the crushed part is more oval and it's not pinched off. It might be more like 10" but I can't remember. The last 3ft of the 1.75" has a bend in it so they are spaced apart a certain amount when they exit below the bumper. My friend who has a welder also does machine work and im almost certain he has pipe bending equipment and he has probably done a couple of exhausts on his mopar cars.

 

Thanks that is super helpful I will look into this using your suggestions.

 

Does anyone recommend what type of pencil tips I should be looking for? Straight through, or turn down? Thanks!

 

I always liked the look of straight thru sticking out the back. unless the turn down dump style are hidden behind the bumper.
for the pencil tip size, again avoid small diameter if you want a tough sound. usually pep boys carried simple 2" chrome ends that I like.
I know a guy who cut the ends off bellflower tips because he liked the size and sound and wanted long chrome pipes out the back. sounded great

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Sorry to keep asking so many questions but I really like the sound in that video clip. Is this what most people consider more of a rumble sound and not as raspy?

Am I likely to get the sound with my 22" brockman mellowtone glasspacks and 2" pipes with my 350 SBC engine? I am guessing I need pencil tips that are just straight through so I don't get a raspy sound? I want the pencil tips because of the nice rolled look with chrome finish. Thanks.

 

that truck has the mufflers further back than i suggested BUT also exits the pipe IN FRONT OF the wheels. which is going to make it a bit more raspy with less pipe length in the system.

i'm still sticking with my original suggestion of putting the mufflers more foward and running them out the back. i daily drove my 64 wildcat set up like this other than dumping to bellflowers instead of pencil tips and never had a drone problem. and several i those years were driving it that was with a "felony hole" in the passenger front floor with a sign and a mat layed over it haha....