Hi all,
Just a list of questions I'm afraid:

I have a 1974 (true dual) exhaust system with a 350 Auto.
The engine is a newer Goodwrench Crate (300 HP - I think)
The Carb / inlet manifold is stock (all emission stuff removed).

It's got the original ramshorns exhaust manifold on it.
And the current exhaust is 1&3/4 inch diameter (or is it 1&7/8)

So to the questions:
1. Is it 1&3/4 or 1&7/8 as standard.

2. I want to stick with the current ramshorns, Can I use larger diameter pipes on these - or am I wasting my time

3. Assuming I can go bigger - how much is useful

4. What is the maximum size to go through the cross member without mods.

5. Now to Mufflers. With this combo. how much flow is needed ?

6. I'm looking at Magnaflows but again what CFM is sensible

7. I don't want to change too much, but if I can get better flow and better tones for a bit of pipe and some mufflers then I'm up for that.

Thanks for any advice.

Jeremy.

(UK based vetter)

 

I think the crossmember has 3 inch dia. holes I used 2.5 inch true duals going throught the cross member. I had headers, but I used 3 inch in and out mufflers to reduce back pressure. Back when these pictures were taken I actually had 3X3 bullet type mufflers to give the car a deep healthy tone. The bigger the diameter of pipe and muffler you use the deeper the rumble sound. So 2.5 with 3 inch mufflers is nice.

thee inch bullets with chrome tips

 

Thanks for quick response.

How do the 2.5" mate to the standard ramshorn manifold ?

Do you need a reducer - or will they mate OK ?

Jeremy.

 

I'd have a shop cut and splice on the down tube from the Ram horns

 

Dude, check out the PYPES vendor here. They have a new 2.5", x-pipe,all stainless steel, mandrel bent exhaust system with slip in type band clamps and straight through type mufflers for $487+shipping. You can get them with the down pipes already made for ram horns. Nice exhaust systems.

THats what I am going to get althought I will buy only the pipes because I like flowmaster mufflers.

 

I have 2.5 inch full duals, with Magnaflow mufflers. They are straight thru, but fairly quiet at part throttle. Pretty loud at full throttle.

 

Hi Jeremy,
I fitted a 2 1/2" dual system to mine & it was the best thing I ever did to it.... apart from fitting an OD trans. Here's what I found:
Fitting the duals in place of the original Y system gave a big seat of the pants power boost, even with the stock mufflers & manifolds. Changing the mufflers to glasspacks "may" have given a bit more power, it was hard to tell above the din at WOT!!!!
At this point the car pulled really nicely, but there were 2 annoyances. The 1st was the drone & the popping in the exhaust at idle. These were cured by fitting an "H" pipe, which also had the advantage of taking the harshness off of the sound by making it more mellow (it also decreased the volume from "beyond loud" to plain old "bl**dy loud"). The 2nd was the way the power started dropping off as the revs increased. Having played with many (70's) emmision controlled vehicles, I knew that it was due to a restictive exhaust. My Vette had the factory tubular manifolds which have a 2" restriction in them, so I lobbed on a set of Dynomax Headers, bumped up the secondary mixture a bit & lost most of the drop off in power (it's still there, but I'm certain that it's due to the stock heads).
So, if you change the system, I'd recommend a 2 1/2" system with a crossover (X is apparently better, but H is fine & a lot easier to fit) & any set of mufflers that aren't restrictive ie. probably most of the performance ones.

When I changed my exhaust I was told by a UK specialist that it would "fall flat on it's face" if I fitted a 2 1/2" system. I think this was because he was trying to sell me his 2" system, but it was BS. My engine was stock, with all the emission controls removed, & it loved the new system. I wouldn't go bigger than 2 1/2" unless I had done some radical mods to the engine & it really needed to breath more. What I've found while playing with bikes is that, generally, a smaller diameter system increases the low end torque at the expense of top end power (and gives a higher pitched sound), while a big bore system, eg, drag pipes, let it breath well at high revs but can make it as flat as a pancake at low revs - which is where you spend most time (and gives a nice deep tone).
In a nutshell, from experience, I'd fit 2 1/2" duals, with an H pipe & probably go for the Magnaflows, or something similar. It may be worth taking the plunge & getting a set of Headers on there & having a custom exhaust place hook up the rest of the system, as it'll work out a lot cheaper in the long run if you decide that headers are needed at a later date!
To make things easy, if you're keeping the manifolds, you could just get the Mid America true dual system that bolts up to the stock manifolds. That's what I originally did, but I ended up selling the system after fitting headers
Cheers

 

Paul,
Thanks, as I suspected - I think my main questions relate to stitching a 2.5" to the smaller Ram Horns.

I have taken ajrothm's suggestions on board which tie up well with yours.

Have a look at:
http://pypesexhaust.com/sys-vette1.html

I've sent them a load of questions so we shall see if they wish to deal overseas......

Yours,
Jeremy.

 

Hi Jeremy,
They look good. I wouldn't bother getting the polished version though. I spent ages polishing my system after I made it & later discovered that there's an engine oil leak & a trans fluid leak. Neither leave a puddle on the floor, but that's because the oil & fluid runs down the exhaust system & burns onto it, making all that polishing a complete waste of time!
If they don't do International shipping then you could contact Steve of Moving Parts and get him to ship it over (it would be worth getting a quote from him anyway).
Cheers

 

Jeremy, We've tried to send you e-mails to both your e-mail address's and they are being returned. Here is the information you requested.

1. I assume I would need DCC10 to connect to the system - is this a = standard fit to the 2" Ram Horn type manifold - do you supply the seal / bolts ?

This is a standard fit to the Ram Horn Manifolds. We supply the flanges only.

2. I guess I also need tips (The 1974 had down turned exhaust tips) But couldn't quickly see anything that looked similar on the website. or is the system complete with tips ?

The system comes with 75+ style polished stainless tips. We have not reproduced the rectangular tips at this point. We plan to = do so but do not have a date.

3. Could you tell me the flow (in CFM) of the Street Mufflers as opposed to the Race Mufflers.

Race Pro's approximately 490 cfm. Street Pro approx. 340 cfm. For reference, a FM40 series flows 286 cfm, but don't worry so much about flow with a 350 crate motor. The 2.5" mandrel bent pipes will give you the flow you need. Base your muffler decision more on sound.

4. What is the overall cost of such a system ? (I can't see a price for the DCC10)

$576 is the pre-production special including DCC10 downpipes.

5. I'm in the UK, can you ship to the UK, if so at what cost ?

Rather expensive. I would guess $200+ the box is too big for USPS. It would have to ship via a company like DHL.

6. I see there is a warning about 'some cutting may be required' is this to the exhaust system - or the chasis ?

That is a general note about most of our performance exhaust systems, not the car. For the C3 System, it is unlikely that there will be any cutting necessary. It's designed as a bolt on system.

 

Ccass,
Thanks so much for the reply - I can only assume that your slightly 'explicit' e-mail address is my problem !!

Could you let me have the box dimensions and weight for such a shipment (I know your website has this info - but it doesn't include the DCC10 bit).

Looking at some of your posts on chevytalk I'm guessing the Race Pros are less tinny at idle than the Street Pros - is that correct ?

And the Race Pros are slightly quieter at high revs / WOT.

If my two assumptions above are correct, then I'm more interested in the Race Pros (who wants a tinny exhaust note )

Again - sorry about the e-mail issues - I'm only glad to have made contact somehow !!

Jeremy.

 

My 82.....stock ram horns to 2" true duals very small cat and flowmasters. The freakin car rumbles at idle and it is hard to have a conversation with someone in the garage with the car running!

 

Well there's your problem right there:

Get it out'a the garage and drive the damn thing

J.

 

lol...I dirve her at least once a week.

 

...the car that is......

 

The box dimensions stay the same. The downpipes should fit in the large box so the price should be around the same. The Race Pro's will be louder at WOT because they are a straight through design. At all other levels, the Race Pro's are quieter.