....: Exhausting Work

17 June 2011

Exhausting Work

I know it doesn't look like much progress since the last engine start video...I did take a long break during the winter, after all!! After fretting about the exhaust system; deciding to install factory side pipes, selling the headers I had, finding out the fine state of CT won't register my car since the only year for C3s with factory side pipes was '69 (fortunately, I had not sold the MagnaFlow exhaust system I had), and deciding to go with headers again. Phew!! I have got to get this thing done...I have too much time to think and change plans.

Anyway, the Melrose headers were supposedly designed to mate up with the factory exhaust. Well, they don't. As you can see in the pix, they hang way low and out board of where the factory pipes would normally be. On the C3s the exhaust pipes run through two holes in the tranny cross member on either side of the tranny mount bracket. In fact, the tranny mount and the exhaust bracket share the same mounting holes.

This caused quite a dilemma since I had to figure out a way to fabricate the connection between the headers and the exhaust pipe. It called for two 45 deg bends to go from the header collector to the pipes in the cross member, basically an ess bend going up from the collector and inboard toward the center of the cross member. The dilemma was that I don't have access to a local shop that can mandrel bend. Eventually, I found a vendor on EBay that provided two 2 1/2" pipes per side. Steve Makos, the manager of the local Midas shop, worked with me by expanding the pipes on one end to 3" to fit the collector and the other end to fit over the other 2 1/2" pipe. I had to cut each pipe to custom lengths to fab the connector pipe. The pix below the video will show all this.

Since I went to all the trouble, I JUST had to hear the new exhaust system. The first engine start video in an earlier post was with the factory manifolds only - no exhaust. In this video I have the Caddy CTS-V dbw pedal installed in the car and connected to the computer (ECM). The ECM and the temp ignition switch are sitting on the little table between the car and the chassis. It sounds real nice. (the ticking at the beginning of the vid is a vent fan in the garage)

The gap between the header collector and the exhaust pipe at the cross member.

Two elbows used to form the new exhaust pipe.

Fitting, cutting.

...and installed for mock up. Steve Makos at the local Midas shop expanded the ends for me, in spite of all the measure once - cut twice trips I took to his shop. Couldn't a done it with out him. Yesterday I practiced welding on scrap pieces of pipe and today I tacked the two pieces and pulled them to weld and paint. BTW, my very first weld job - they looked like crap, but I ground them to look passable. This pic shows them BEFORE my weld job.

The MagnaFlow muffs. The twin pipes will fit in the stock exhaust ports.

1 comment:

Anonymous03 October, 2011 23:00
Awesome work Clint thank you so much for taking pics and doing such detailed step by step instructions. Custom Made Performance Exhaust Systems
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1973 Corvette Project

This blog will chronicle the tale of my '73 Vette project car. I've been a Corvette hobbyist since my first vette, a 1973 silver with black leather interior, L-48, 4 spd coupe. It was my first, and only new, Corvette. Subsequently, I owned a total of seven Corvettes; a '77 coupe, '68 roadster, '80 L48 4spd, '73 coupe, '94 coupe and this '73 project.

It's obvious that the '73 is a favorite of mine. I found this one in an AutoTrader in October of '06. After talking and negotiating via email, I decided to buy it. It was an original BB, 4 spd car with 52,184 miles on the O'meter.

Now this is all according to the guy I bought it from. History of the car:

The seller's uncle bought it from the original owner when it was six months old. He pulled the BB and hot rodded it with a SBC for years, garbaged out the interior by cutting holes in the door panels and rear compartment doors and back of the compartment for speakers. I shouldn't bad mouth him, though. I cut a hole in the passenger side dash panel of my first '73 to mount an eight track (yes, I'm that old!!) player so it would look factory.

Then he passed away and the seller's older brother had it for years until my seller got it. He pulled the SBC but never told me what he did with it. He installed the following: new 4-core radiator, new shocks, new calipers and rotors, new rubber bushings in the suspension (missed the trailing arm mounting and control arm bushings, though), all new heavy duty u-joints, new windshield, and pulled the gas tank and had it cleaned and sealed. It had the CenterLine wheels you see in one of the pictures and the aftermarket hood scoop.

It was located in East Mesa, AZ in a desert suburb of Phoenix and I towed to my house in Flagstaff, a distance of about 160 miles from a elevation of around 1,000' to 7,200'. The trusty old Dakota made it.

The first thing I did was buy a set of '72 stock ralleys, rings, and center caps from a guy on the corvette forum and mounted 234/15 BFG Radial TAs on them. I will eventually put a set of 17x8 Vintage Wheel copies of ARE TorqueThroust Originals on it. I found a stock '75 hood to replace the existing hood w/scoop. When they put the scoop on, they cut a hole in the stock hood for the air cleaner, making it impractical to glass back to original.

Then I towed it on a U-Haul trailer 2,500 miles to CT it with the poor old 2000 Dakota that had 184,000 miles on it.

My plans: My original intent was to put an old school SBC in it. Then I thought about a GMPP Ramjet 350. I just sold a '94 Vette with an LT1 in it that I was going to upgrade to a LT4. I have the LT4 heads, hot cam kit w/1.6 rr, and an LT4 intake that I had the top ribs polished and cleared. So I planned to build an LT4 to drop into the '73. Meanwhile, I'd been watching EBay for LT and LS motors. I've also been following a thread on the corvette forum on LS-C3 conversions.

Well, I bid on on EBay for a LS2 w/5,800 miles on it that was still in the '07 vette, won, started a dialog with the owner, Ray, and started doing more research. Ray just installed a custom built LS7 last week in his '07 and pulled my motor last week and crated it for shipping. I used some FF miles I had to fly to Seattle to see the LS2 and rode in Ray's car. I'm sure Ray will post some info and pics of his new motor and ride.

Ray has been a great guy and a source of a ton of advice on the LS2. I talked to Dan at Vetteworks, the folks at SpeedHound and SuperPowers, Josh, from the corvette forum. Josh and I have pm'd and spoken on the phone about my conversion and he has really been an absolute wealth of information.

I'd like to thank Josh and all the other gear heads who pioneered the LS-C3 conversion and who are making this project a lot less a blind drive like I thought it would be.

I'll install a T56 6 spd, upgrade the suspension and steering, redo the interior (I bought a set of '04 ZO6 black leather searts for it, too), do some minor glass work and try to paint it myself.

Okay, from here on my updates will be on posts. Jump in with comments and suggestions. Any one in the SW CT area who has some knowledge, wrenching skill, cold beer, or the need to supervise, give me a shout - an extra wrench and a torso that can bench press a t56 6 spd are always welcome.