[Aggisport]

Im just about finished with my 289 and ready to start it up and break in the cam. I purchased a Magnaflow exaust but it needs some modification/welding to mate to the manfold. Should I tow the car to a muffler shop to finish the exhaust or just start it up and break in the cam first then drive it to the muffler shop? What would you do if you were in my spot.

Thanks

Jason

 

[Travis98146]

I'd weld up whatever was necessary to hook up the exhaust. But then, I have the welder and the experience to do the work. However, I have run new rebuilds for 5 or 10 minutes while they sat on an engine stand.

 

[Klutch]

You can run an engine as long as you like with exhaust manifolds or headers. Just don't run it without manifolds or headers. It will just be LOUD.

 

[ophthos]

I bought some cheap mufflers form O'Reilly and flaxible down tube. Attached them to my headers and broke in the engine. Bit load but doable.

 

[LeeFred]

I broke my engine, and a few months later broke my engine IN just with the headers and nothing else. I like the sound, but one of many reasons why my hearing sucks.

 

[Redneckgearhead]

With headers or manifolds, sure, BUT wear hearing protection.

 

[xcelr8]

I have same scenario once the car comes back from paint. I plan on cheap flex tube from auto store and either borrowing couple mufflers from derby friend of mine or just getting cheapo's from store. Really dont want to break it in for 20 min at 2k RPM in my subdivision... or do I

 

[Target]

I was under the impression the potential for burning a valve is much higher if you're running it straight out of the manifold.

 

[Lizer]

You don't need a welder, you could just use exhaust clamps. You can put manifolds on it and a short length of flexible exhaust pipe that runs to a cheap set of mufflers.

Or if you have dual exhaust that was originally on your car, cut a length of if off where it bolted to the manifolds, bolt to manifolds, and hook a muffler up to that. Or don't use a muffler. It's just loud, but sounds rad.

I drove my car around my property with open headers when I first got it running. When my teeny bopper sister was out she wanted to go for a ride I didn't tell her about the open headers though.

 

[Huskinhano]

I would recommend mufflers. That way you can better listen for any expensive sounds. Use water too. If you have to dump it because of a bad gasket, it's only water. When you know everything if fine, antifreeze.

 

[Hemikiller]

Nothing like 20 minutes of open headers at 2000+ rpms to really get the neighbors going. I broke in a 500" BBF at 10 o'clock at night once. It was in a rented commercial garage, but the nearest neighbor still had a fit and called the state police. The officer showed up a couple minutes after I had shut ti down, so I had to light it off for him...

 

[Nailbender]

I would recommend mufflers. That way you can better listen for any expensive sounds. Use water too. If you have to dump it because of a bad gasket, it's only water. When you know everything if fine, antifreeze.

Exactly! If something sounds funky you need some kind of exhaust to hear it. Could save you another rebuild.

 

[Huskinhano]

Nothing like 20 minutes of open headers at 2000+ rpms to really get the neighbors going. I broke in a 500" BBF at 10 o'clock at night once. It was in a rented commercial garage, but the nearest neighbor still had a fit and called the state police. The officer showed up a couple minutes after I had shut ti down, so I had to light it off for him...

A good 15 years ago was a very young member. I think he got himself banned. Anyway he broke his cam in with open headers at his father's CONDO at 1AM in the morning. Yeah

 

[Mustang4SF]

I was in the same situation. The old exhaust system didn't fit the new exhaust manifold. I bought these cheap and flexible exhaust clamps and hocked it up as good as possible. Was louder for sure, but ok. It is very valid point from @Huskinhano . You might miss engine sounds over a loud exhaust noise.

 

[C6ZZGT]

You can run an engine as long as you like with exhaust manifolds or headers. Just don't run it without manifolds or headers. It will just be LOUD.

I might be able to confirm (or not) that flames come out the exhaust ports when a 289 runs without manifolds or headers on it.

 

[GT_SCODE]

Yep I’m pretty sure I towed mine to the exhaust sho before break in.

Then drove back later to have him adjust it.

 

[sixtysevenGTconv]

Was your 289 rebuilt with roller rockers or orig hydraulic lifters?

 

[sportsroof69]

I ever do initial startups with open headers, because it can mask sounds you may want to hear.

 

[stephen_wilson]

I might be able to confirm (or not) that flames come out the exhaust ports when a 289 runs without manifolds or headers on it.

I remember a friends dad doing that on an old Caddy or something, he just had a scrap of metal on each side to deflect the flames. It was entertaining !