View Full Version : what it the fastest 1/4 mile with exh manifolds

07-22-2002, 05:50 PM
I was wondering what is the fastest anyone has gone with stock manifolds or ported stock,??? vs headers also what hp level stock maff and tb are good to whats most hp using stock injecters, anybody have a list of such things ? maybe a list should be compiled of these things to help others know when its time for upgrades of these parts, and when its not needed yet . so the best bang for the buck can be determined. just my 2 cents if this list exist can point me towards it??

07-22-2002, 08:00 PM
I have headers and my car is slow;O)

07-22-2002, 08:35 PM
The exhaust manifolds on these cars can be pretty restrictive, but I would still rank them behind the resonator and cats.

If you have access to a flow bench, you might want to try and flow test a stock header and then a heavily ported one for comparison.

Although there is no hard evidence (yet) most folks will agree that a set of heavily ported 89-95 stock SC Manifolds will flow about 90% of what a set of Kooks Shorty headers would flow.

The stock exhaust manifolds from a 96-97 Tbird 3.8L N/A will also fit, they are tubular in construction rather than cast iron. But their collectors are a little smaller, so I don't know how those would flow on our engines....

07-23-2002, 01:14 AM
ive ported mine but was just wondering I hate headers but may need them, sorry old pics new setup is being cromed getting ready for aug 24 fomoso bakersfield ca.

Jim Demmitt Jr
07-23-2002, 01:46 AM
I ran 13.088et at 103.535mph with stock ported headers
I ran at Vegas 13.60et at 100mph they worked great

07-23-2002, 01:56 AM
I ported mine Im gonna run ported heads ported exh manifolds, and inverted setup with 36 lbs injectors, 70 mm maf with out post and stock tb first then try 75 mm tb also propane injection so I was kind of worried that exh might not be up to snuff I have exh cutouts going to super traps so when at track i run thru stock exh and cut outs flows free and quiet as stock when cruzing.

Dave Ward
07-23-2002, 09:22 AM
I know Jeff Dillman's Cougar ran 13.4 at Englishtown before he sold it and that was with stock manifolds and stock blower top. I think this run is still hanging onto the top ten.

07-23-2002, 09:30 AM
Manny... you are just the guy.

Everything I dream of, you are doing. Come up with any mods for the rear suspension yet or is it top secret?

Propane Injection
Inverted Blower
Exhaust Cutouts

I'm bumming I won't be there to see it. Don't blow it up, I want to see it next year.

I hope someone get's some good pictures of all your stuff. I'd love to see pictures of how you did the exhaust as I've been pondering cutouts as well.

Keep up the good work.

07-23-2002, 01:48 PM
had new cats done placed farther back about ten inches, cutouts are before cats, have cable hooked to cutouts so I can open when I want from under dash mount,rushing to get done for aug 24, cars in pieces installing gears now , 355s have all parts just need put together, rear suspension all thats needed is to make three 1/4 inch thick spacers place between frame and suspension on two front and pass back not on drivers side it binds the rubber isolators and gets ride of wheel hop really need hard mounts poly or something but this works as a poor mans fix,:)

Rob Noth
07-23-2002, 07:09 PM
Manny, I hope you aren't using those cast iron JC Whitney style cable-controlled cutouts, these are a neat idea but unfortunately not well made or long lasting. A better choice might be a block-off plate style cutout like made by Flowtech. Or Quicktime Performance (http://www.quicktimeperformance.com/qtec_main.htm) makes a really cool electric one.

BUT there is another problem, on the SC where can you put a cutout so that the hot exhaust is directed away from everything? I bought a Flowtech and spent an hour under the car at the exhaust shop, we just couldn't find a way to do it! I'd be interested to see how you fit it in there.


07-23-2002, 07:19 PM

If you could draw a little picture of what you mean by the suspension mods I would love it.

I can't visualize your comment. Maybe use the picture below as a reference?

Did you modify the underbody sheet metal to get your cutout to route exhaust out the side? Or do you intend to just run it for short times so you don't worry about the hot air?

Very curious as I've been thinking about sidepipes if I do some structure changes underneath with a sledge to make a path. Heck, if they can get side pipes on a Viper, why not an SC?


07-23-2002, 10:24 PM

07-23-2002, 10:27 PM
It's good, but a little small. Can't read the text. But it looks like you are placing washers on the subframe mounts rather than the actual suspension arms.


07-23-2002, 10:32 PM
the subframe mounts are where our wheel hop is comming from the wheel is moveing front to back and tyoe in and out not up and down as was thought beforeits the whole enchilada moveing around the idea i came up with binds the subframe and makes it solid worked on mine no wheel hop..tried to load pics but it says they are to big had to shrink them

07-23-2002, 10:34 PM

07-23-2002, 10:34 PM
Good work manny. thanks.

07-23-2002, 10:53 PM
So you guys know.. neil Frisbee ran 12.4's with ported exhaust manifolds.. This was before headers were made for the SC's

07-25-2002, 10:58 AM
So generally ported exhaust manifolds are decent enough? At what hp should you really switch over to headers? I ask because I have an opportunity to get a spare set of stock manifolds and send them to be ported out (on the collector). Way cheaper than headers. But in the future if I do a complete rebuild, nothing too extreme, and I have the heads ported and polished, and the manifolds port matched... Will I still be ok without headers? When all is said and done I'll probably be looking at 300-350 hp.


07-25-2002, 02:57 PM
I think conservative estimates have put 400 hp the ceiling for stock manifolds.

Understanding that if you are buying enough equipment to hit 400 hp, you better be willing to do the headers as well.

Long tube headers are much more useful than short tube.

07-25-2002, 03:28 PM
So how much hp does an "average" rebuild add? Without getting into specs, but rather to say a rebuilt engine/heads- that would result in a reliable engine, preserving reasonable decent fuel economy, and still be a stronger/faster engine than a modded stock engine. This would be my goal when it comes time for a rebuild. A strong, well balanced, reliable engine.

My guesstimate is 300-350 hp. In which case I'm good with the manifolds instead of headers. But since I'm not sure how much hp a rebuild would add for me... Well, kinda vague, but take a shot!

07-26-2002, 11:21 AM
An average rebuild takes you back to stock.

I wouldn't do an average rebuild on our engine. Now the average performance rebuild would likely get you to 350 at the wheels assuming you add the intake goodies as well.

Stock you are looking at 190-210 hp at the wheels. Engine rebuild alone is not going to get you 150 hp.

But a quality rebuild is going to require some serious head work and likely a custom ground cam.

Then on top of that you'll be looking at new injectors, new MAF, new TB, new SC Top, new fuel pump, updated supercharger. Assuming you are going to just use Nitros injection with more stock parts.

There are many facets to making the SC go. Other than the heads and cam, the main benefit of the engine rebuild is to add durability. Balance that engine, get rid of the casing lines, remove stress points.