Dual Exhaust Question

[1989GMCSIERRA]

91-93 Chevy Caprice police interceptors had factory dual exhaust, no crossover. Must not be necessary

The old Crown Vic's (up to '88) gad dual, no crossover. Must not be necessary.

Fox body and SN95 Mustangs had a crossover with the same 5.0L

I'd say: performance car/performance engine yes. Truck no.

crown vics came with dual exhausts up to 2011 when they stopped the production. They came with a H pipe built in. they also had a dual exhaust into single exhaust (really depended on options but they came with both single abs dual exhausts throughout the years. The hp difference was 10 hp between the single and dual exhaust equipped vehicles. The police package had a recalibrated PCM for another 10 hp for a total of 250 hp max rating. It was calibrated for a higher top speed. But the engines themselves were identical to civilian versions at 230 hp or so.
Back in the day I read a car magazine did a x and H pipe on a car. I don’t remember much but I remember they said it was a good thing. I think it just equalized the pulses

 

[victor II]

When my dad bought the ‘88 Silverado C1500 (350 C. I.) I now drive, he wanted a new exhaust system. He settled on a 3” terminating into a Flowmaster 1 into 2 that exits behind the passenger side tire. It sounds great and helped a bit with performance.

 

[kenh]

Way back when , when I thought I wanted to spin wrenches in a dealership I went to our local community college to the auto tech classes. Our instructor told us a 90 degree bend has the same restriction as 10 feet of strait pipe everything else being equal.

Just a bit of useless info.

Ken

 

[Postmech]

A balance pipe or x pipe is always a good idea. It changes the sound frequency so it sounds "better". I had 3" pipes and chambered mufflers on my hotrod, sounded so much better and quieter after I added balance tube. Its not really quieter, it just sounded that way. Especially inside car. A good flowing exhaust is easy horsepower. Plus it allows engine mods to be fully effective.

 

[badco]

471 horse ona stock 350?!? Where’s the BS flag...

Would you like to see the dyno sheets on it? Maybe the 305s we did at 441hp? O or the 68 Camaro 302 at 541?

Stocker cams are a special grind. They may have stock lift but you can move LSA angles and LCL around. Plus they are ground with very aggressive ramps, or at least that's what I remember. Also everything else is optimized to the limits of the rules. Valve angles, spring pressures, chamber volumes are perfected. Back in the day, you might flow dozens of heads to find the best pair. Of course this is all old, obsolete sh#@, from the 70's, lol. Check some of the times they run, it's amazing.

Cam is changed on duration, lobe separation, actual diameter and anything else we can to get a little extra. Coated tool steel lifters, 240# seat pressure on stock diameter springs, Heads are still picked over for best castings, usually flow 230cfm @.400 lift on good ones. Intake will take about 8hrs to get it finished after we "cleaned " it out. Finding 18hp in a ring pack and hone combination while tripling thier life was best improvement we found in last few yrs.

 

[b454rat]

you need to call guiness then, cause they are the most powerful STOCK SBCs ever produced.

 

[kennythewelder]

 

[Schurkey]

On a nhra stock eliminator 69 camaro 350 low compression engine...

you need to call guiness then, cause they are the most powerful STOCK SBCs ever produced.

Pretty obvious that "Stock Eliminator" isn't a "stock" engine.

 

[b454rat]

Pretty obvious that "Stock Eliminator" isn't a "stock" engine.

Yes but not what he's saying

 

[1989GMCSIERRA]

Would you like to see the dyno sheets on it? Maybe the 305s we did at 441hp? O or the 68 Camaro 302 at 541?

Cam is changed on duration, lobe separation, actual diameter and anything else we can to get a little extra. Coated tool steel lifters, 240# seat pressure on stock diameter springs, Heads are still picked over for best castings, usually flow 230cfm @.400 lift on good ones. Intake will take about 8hrs to get it finished after we "cleaned " it out. Finding 18hp in a ring pack and hone combination while tripling thier life was best improvement we found in last few yrs.

Depends on your definition of “stock”

As you stated I can see getting that hp IF you picked and chose the parts that go into a build from the high performance stock parts.....say Vette roller rockers, better or LT1 cams valve springs pistons crank, maybe big flow stock heads, high flow exhaust etc. tune and play with fuel and air ratios, massaged the intake, heads, exhaust coated pistons etc....sure it’s possible.

but at that point..... You’re describing a specifically made engine with a lot of trial and error to get to those hp numbers. Now i applaud you for getting such numbers but......there ain’t nothing stock about a stock car applies here.

The definition of a stock engine is a engine that comes in a regular production vehicle.