Dual exhaust using stock manifolds

[burgundy83]

I've been considering headers for a while, but I'm not sure they're worth the money on a 30 year old 305. I'm wondering if I just cut off the crossover pipe and weld a plate over the hole in the pass. manifold, and run 2 pipes side by side down the passenger side and then run the one pipe back to the driver side just before the rear axle. That would save cutting up my trans crossmember and buying headers. Has anyone done this or know how doable/livable it would be?

 

[bill]

I've been considering headers for a while, but I'm not sure they're worth the money on a 30 year old 305. I'm wondering if I just cut off the crossover pipe and weld a plate over the hole in the pass. manifold, and run 2 pipes side by side down the passenger side and then run the one pipe back to the driver side just before the rear axle. That would save cutting up my trans crossmember and buying headers. Has anyone done this or know how doable/livable it would be?

A good exhaust shop can fab that up for ya...shouldnt be too expensive.

 

[DoubleV]

Since when did Chevy 305's have exhaust manifolds with a crossovers like the Olds had? :?

To answer your question, yes you can basically run true duals going down the passenger side. Given enough room, you can technically run pipes anyway you want.

 

[Peter]

thats exactly what i did with my olds 350. cant speak for performance because i never drove it with the crossover but i wouldnt be surprised to see an extra 5 HP

 

[Bonnewagon]

That works, I did it with my 301. If the pipe is in good shape, I wouldn't cut it up since most old head pipes are getting very hard to find. You might want it some day. I try to use junk head pipes or generic flanged pipes from an auto store.

 

[Possumz]

Im courious about this set up as well. I would love to do this with the Monte Carlo and tap into the 442 exhaust that I am using for my duals. What dual cat is being used and does anyone have any photos that they can post up for us.

 

[axisg]

I've been considering headers for a while, but I'm not sure they're worth the money on a 30 year old 305. I'm wondering if I just cut off the crossover pipe and weld a plate over the hole in the pass. manifold, and run 2 pipes side by side down the passenger side and then run the one pipe back to the driver side just before the rear axle. That would save cutting up my trans crossmember and buying headers. Has anyone done this or know how doable/livable it would be?

I had installed the larger truck exhaust manifolds and ran duals off those in the early 90's with my Cutlass. Honestly though it sounded much better I didn't gain anything noticeable power-wise.
However years later on my Monte I installed a used set of TES headers ( they utilize a crossover and bolt up to you existing cat-back ). After the install I noticed more power at a lower RPM. I only paid $150 or so for the headers so it was def cheaper than full exhaust and allowed me the time so save for a cat-back system. When I installed the cat-back it sounded great and made a little more power than before but nothing as noticeable as the headers.
BTW I still run this exact setup with the 5.0 gone and the 5.7 in its place.

What dual cat is being used and does anyone have any photos that they can post up for us.

442 / Monte SS / GN all use a Cat-back system with a 4 bolt flange off the back of the cat. which then splits to Dual exhaust
http://www.heartthrobexhaust.com/2008488p.html

Honestly if you don't want to hack up your crossmember but want a little more performance/sound; then scour CL and the forums for some shorty headers with a crossover( TES, Hooker each made a set ) and a cat-back system. Your 305 is a SBC so any exhaust system you build now can be utilized if you decide to change your motor down the line. Or if you just want the look and sound of duals then use a single in / dual out muffer and dump the tips behind the rear wheels.