327_TPI_77_Maro

iTrader: (8)

Has anyone with a fairly fast 3rd gen (faster than 14.00 1/4 mile) directly compared either dyno #s, or 1/4 mile passes, before and after swapping from 350 stock manifolds, with no other changes (or as few other changes as possible, maybe just other exhaust mod's), to headers?

OR-- has someone compared between shorties, and long tubes, on a 3rd gen? I am trying to decide how much exhaust I "really" need for a 13.0 street car.

I have a 327 w/ Comp 276 retrofit hyd.. roller, 2.02/1.6 200cc World heads, holley stealth ram, built 700R4 w/ Raptor 5x converter, 3.42 posi, wideband, self tuning, etc. The engine is coming out of a 2nd gen I have been running for years.

The more I look at pics of people's long tube setups on the third gens, w/ the hookers, the less I want to use them. The custom Y pipes get really messy and what I consider good ground clearance, is a little more conservative than some people. I weld but I don't want a messy nightmare exhaust setup w/ headers that hit the body.

I have a stock pair of the bigger 350 TPI manifolds, w/ the 2.5 dual into 2.75" stock type Y pipe, single cat, and mandrel bent 2.75" replacement type exhaust.

If the difference between the good 350 manifolds w/ the 2.5"/2.75" y pipe, and long tubes is 15-20 hp or a couple tenths in the 1/4, then I really don't care, I will keep the manifolds. If its a really big difference ,maybe 4-5 tenths ,then I can't overlook the power gain of headers and I"ll have to figure out what headers to use at or around a 13.0 street car.


The shorties don't look like they are worth using on these cars at all, over the 350 TPI manifolds. The funny thing about the shorties, is that the ball flanges they have w/ a 2" outlet in the center of the ball, is actually a lot smaller than the stock manifolds. Can the crappy shorty headers really be any better than the 350 manifolds w/ the big stock exhaust? They really don't look like they will be any better at all. Heck pushing through a 2" hole in the ball flange looks worse than stock.

stroker_SS

The 2" outlet is on the hooker 2055's and that can be opened up also. however i have the hooker 2460's and those have 3" outlet on them so not all shorties have a 2" outlet for our cars.

327_TPI_77_Maro

iTrader: (8)

I assume those use the triangle 3 bolt flanges. I really really want to avoid the 3 bolt flange at all costs. They never ever seal well enough for me, and I run 2 o2's so an air leak is the kiss of death. Although I have the weld on $65 Flowmaster ball flange header reducer kit, that has a much larger ball flange than the pipe, so it is not a restriction. I suppose I could add those to a 3 bolt flange header after cutting the flange off.

Orr89RocZ

iTrader: (20)

hooker 2055's use a 2 bolt flange...not even a triangle. The opening is more like 1.93 inches and i was able to get 2.25inchs with some grinding/porting Could probly get 2.35 and still seal well.

I dont have numbers but i did notice a nice gain on the street by the seat of the pants over stock ypipe/manifolds when i went to the hooker 2055s with stock 1.93" opening and their mandrel bent y pipe. It was enough exhaust to make my 3400lb car go 12.9's with just a bolt on L98.

Sure a longtube may have made another 10 hp. its not worth it tho on a mild modded car.

I dont think stock manifolds would allowed me to go anywhere near 12's. they were pretty crappy compared to the hookers. Even tho the small opening at the colllector, they still make good power. I would say the hooker shorty/ypipe combo added 15whp and the catback about 10. That brings a 215whp stock L98 up to around 240hp or so where i estimated my car was at with TPI. I put down 254 with the HSR running lean with few other mild bolt ons. The HSR probly only added a few ponies 5-7 up top end but really shifted the powerband up higher which helped me run faster ET's.

So shorties over stockers do have good gains, and Shorties will be plenty for that car for a 13.0 et range.

327_TPI_77_Maro

iTrader: (8)

Yeah I just don't think I can sleep at night putting headers on with a 2.25" collector (effectively). We'll see. I spent $1000 on just the cam and lifters in this engine and now I want to cheap out on headers....LOL. I am just used to 2nd gens where you can get a great set of 1 3/4" tube long tubes for $175. Thanks for weighing in though. Is your HSR'd 350 a MAF car like mine?

Orr89RocZ

iTrader: (20)

yep stock L98 89 using 89 MAF system. Ran great for the mods. The hookers were fine for that motor. I really wish i could have gotten SLP 1 3/4" or Dyno Dons tho.

that may be your best bet for goooood shorties that fit 3rd gens. Dyno Dons headers. PM him

327_TPI_77_Maro

iTrader: (8)

I don't need coating or anything really fancy. I definitely don't want $800 headers/y pipe. It looks like I might just take a set of 1 5/8 or 1 3/4" regular shorties and then cut the flange off so I don't have to deal with the huge bottle neck, then make my own Y. If the ***** on the headers you have could be opened up to 2.5, that would be close enough for me. Do you think that would happen and still seal? Do they make that header in painted?

Sonix

iTrader: (1)

Just a side note. I have the hooker 18740 or whatever they are. The older ones with the 3 bolt triangle flange (which is indeed junk).
I'm in the process of replacing them with the ball flange.
Actually;
This is exactly what i'm doing, flowmaster and all.

I haven't finished it yet, and i'm waiting to finish my engine. However i'm thinking it might be a nightmare to line everything up and weld it in place correctly. Not a lot of give on that. If you do this, let me know how it goes.

Orr89RocZ

iTrader: (20)

i think it would be very close... but more than likely be a tad large. I went 2.25 and still saw some carbonation around the ball flange so i know i could have gone alittle larger but i dont think more than 2.40

you could do that 2.5 tho, and modify the ypipe flange area by getting more material welded on, or flaring it out more, or running a custom 3in y pipe thats flared more to cover the ball flange.

327_TPI_77_Maro

iTrader: (8)

Sonix I will, it sounds like the route I may take. I can't spent $850 on shorty headers and Y pipe. It just isn't worth the cost to benefit ratio. I originally bought the Flowmaster ball kit to use on the long tubes in my 2nd gen, because the triangles always leak (worst flange design, EVER), but never got around to it.

What brand shorties are you going to weld the ball flanges on to? I don't think it will be a problem lining them up. I did an exhaust system piece by piece on a V8 swap into a 1966 Dart, which is the narrowest car ever. I had to loop the exhaust around the steering and actually come forward and down and around before I could go back. It was pretty wild looking but it cleared everything fine. This won't be anywhere near that bad. I don't mind cutting and taking it in and out 50 times to check fitment if it saves me $500

IROCThe5.7L

I know this isn't really what you're looking for since it's not faster than a 14.00.


Bone stock (Stock catback also, just had an 80 series muffler) = 14.8@94

Nothing changed except Hooker 2055's/Ypipe = 14.4@96


60 ft's were very close also.

Orr89RocZ

iTrader: (20)

if yoru really worried about performance losses, which i feel will be enough to warrant getting longtubes over stockers, and you cant justify shorties/y-pipe, then just get long tubes like hooker 2210's or headman 1 5/8's.. since you dont need much more than 1 5/8" primary.

hedmans are pretty cheap compared to the hooker 2210's i believe. There are Doug's headers which are like the hooker 2210's but cheaper. Stainless works makes a 800 dollar set that tucks up nicely in thirdgens. No loss of ground clearance..hawks sells them.

Any of those will work. I wouldnt run the stock manifolds.
----------
that car is capable of 13's now with that trap speed. Just goes to show that even a mild modded car picked up alot of power with shorties over stockers, you can image the gain being more on a more modified car that really could use extra exhaust abilities

stroker_SS

I absolutely despise exhaust leaks, so i used flowtech aluminum collector gaskets with the supplied hardware. Zero leaks. 21 bucks at advanced auto.
----------

327_TPI_77_Maro

iTrader: (8)

IROC, thanks. That is still useful information. $800 headers are not an option, I might just get the cheapo long tubes and build my own Y pipe. The car will get driven under 1,000 miles a year so although ground clearance is some issue, it's not like I daily drive it in and out of parking lots. Crap. Thanks all

InfernalVortex

iTrader: (4)

I went with my Hedman LTs just because they were the cheapest headers around... lol. I dont regret it.

327_TPI_77_Maro

iTrader: (8)

I think I'm going to have to go that route, after looking at what $850 gets you in shorties. I'll build a Y like mw66 showed in his other post. Was hoping to finally have a bolt up exhaust but when you don't like what is out there.... you make it. Dammit. LOL

1989GTATransAm

iTrader: (3)

The single biggest change I have ever made on my car was going from stock manifolds and exhaust to the SLP 1 5/8" tri-y headers and catback. Going by the butt dyno it was significant. None of my other many changes were as big as that one going by the butt dyno.

327_TPI_77_Maro

iTrader: (8)

Track results/dyno #s are much better than butt dyno. Butt dyno can be very deceiving.

Dyno Don

iTrader: (7)

If you think those large outlet manifolds are good, you need to look up inside them and see what is feeding those large outlets.

In an actual test done years ago, I had a '68 Camaro 396 375 HP. I did all the maximum tuning possible with 2 1/2" cutouts on the manifolds, the ran it down the track ...the best was 12.09 @ 113.
Then went back to the pits, changed out the manifolds to LT's, the next pass was 11.66 @ 122.11

That's real world testing.

327_TPI_77_Maro

iTrader: (8)

OK good info. 0.43 ET loss for stock manifolds is really not that terrible when you look at the difference between a lump of iron and tuned long tubes. I think I'm going to drop the 327 in w/ the manifolds and do my own comparo w/ some dyno runs, before and after headers, just for the hell of it. I always put headers on everything but since this car is a little more involved than an old car where you can just plug and play $79 headers and go, I am going to have to wait a few months. There is a dyno a few miles away and I know the owner. Thanks for the good info guys, it really has helped, I'll def. do the long tubes and build a Y pipe when I have more time.

Orr89RocZ

iTrader: (20)

.43 seconds when your dealing with a 11 second car is HUGE. Look at the mph he gained! 113 to 122 is GIGANTIC! Thats a TON of power left of the table with cast manifolds vs longtubes for that motor. Properly setup 122 traps is good for high 10's.

BUT on a weaker motor i dont think the gains will be as much.

327_TPI_77_Maro

iTrader: (8)

Orr89, shhhhhh! I'm trying to convince myself that it will be okay to have to drive my precious motor through manifolds for a couple months. LOL

89formula350b2l

iTrader: (11)

I myself now am torn between purchasing Dyno Don's shorty 1 3/4 headers, or trusting an exhaust shop to custom build a y pipe for the hedman 1 5/8's.

Orr89RocZ

iTrader: (20)

lol i know! Thats why i mention on a weaker motor the gains may not be as significant There will be gains with longtubes over the manifolds but how much more is hard to say when your talkin about a 13.0 car. If your trying to save a few bucks at the moment, go ahead and run the mani's. Car will still work good. Atleast you'll know you have more left in it.

As IrocThe5.7 mentions, he picked up .4 ET and 2 mph with a full shorty/exhaust setup over stock. 2mph is good indicator of the power made, could be 20whp total. The et is a function of traction so who knows how those runs compare. I know i hit 14.0 at 94mph before and 13.6's at 96.6. So you may only gain .2 ET, maybe less. Either way thats more comparable to your case since his motor is closer to yours than a 375hp 396

If you would like, you can have the manifolds extrude honed i believe high flowing but looks bone stock ultimate sleeper

else keep browsing classifieds for good deal on longtubes I"ve seen them

327_TPI_77_Maro

iTrader: (8)

Extrude honing is a huge waste of money, it achieves very little. I've seen pics of extrude honing, comparing a non honed manifold to one that had the work done, and the difference i pretty laughable, especially considering what places charge for it. The guys that run in stock classes do it just because they don't have any other option, but there is no way I would do it on a street car. It's not about money but more about time right now (at the same time I won't spend $850 on shorty headers no matter what). If I am going to bother doing the custom Y w/ the LT's I need the time to do it right, and I am still finishing color sanding and buffing the car that is going to get the 327 (which is still in the other car). Too much goin' on at the moment.

Trust me, the car won't sound like a sleeper w/ the 0.502/0.510" roller cam in the 327. The idle note is extremely choppy.

Orr89RocZ

iTrader: (20)

i see what you mean. Too bad you werent asking about this around a month ago or 2. i had sold my hooker 2055's with ypipe for 250 shipped

327_TPI_77_Maro

iTrader: (8)

LOL thats okay. It sounds like I am going to want the long tubes anyway. The y pipes that come with the shorty headers are pretty nasty looking for this car.

JamesC

iTrader: (5)

For whatever it's worth, the following info from Car Craft (Sept. 04). The 350 HO Deluxe dynoed, with cast-iron manifolds and a dual exhaust with generic 2 1/4-inch turbo mufflers, at 354 lb-ft of torque at 3,800 rpm and 320 hp at 5,600. Hedman 1 5/8-inch long-tube headers with no other changes delivered 383 lb-ft at 4,000 and jumped the hp to 341 at 5,400.

JamesC

327_TPI_77_Maro

iTrader: (8)

Another good piece of info, thanks

Orr89RocZ

iTrader: (20)

thats what i was figuring...about 20-30 hp gain for a 13.0 motor or so, as long as the rest of the exhaust is gooood. Maybe thats not quite justifiable at this moment?

327_TPI_77_Maro

iTrader: (8)

Speed is always justifiable in my mind, lol. I just don't want to pay much much more than the LT's for inferior performance. That doesn't make any sense.

rjmcgee

When I did the heads and 274 cam in my car I ran out of money for the exhaust so I put her together with with the monifolds and stock y pipe/ catback. It ran fine. I trapped 99 mph with it that way.

When I went back and and put in Headman shorties with the Y pipe modded to 3 " after the y and a Banks 3" catback I trapped 105mph. But I also switched out an 600 Edelbrock for a 650 Demon at the same time. So it's not a real honest back to back test.

Orr89RocZ

iTrader: (20)

I got yah. I'm really curious how dyno dons 1 3/4 inch shorties would compare to hedman 1 5/8 longtubes. I believe the 1 3/4 longtubes will pull more power out but it be close with the hedmans smaller tubes. Eitherway, the hedmans probly are the better bargain

327_TPI_77_Maro

iTrader: (8)

1 3/4" tubes are adequate deep into the 11s on a lot of combo's. On a moderate combo that isn't going to be the deciding factor for me, esp. at the price differential. I have a guy who has a set of used LTs for a pretty good price, if they look good in pics I'll take them. I am going to take the trees off my manifolds, cut the flare nut ends off, drill the tops of the headers, and weld the trees onto the headers. Presto, emissions friendly. I won't have to go through emissions but I am going to try to keep this car as clean burning as I can, without giving up power.

89formula350b2l

iTrader: (11)

the exact question i am pondering....but i am not sure if i would trust a exhaust shop to fab up a good y pipe...and for a good price either. I havent heard any fitment issues with Dyno Don.

327_TPI_77_Maro

iTrader: (8)

I wouldn't trust an exhaust shop either. That's why I'm going to weld up my own Y pipe. Stafford eh? I'm in springfield. I have an HSR'd retrofit rollerized 327. It's a mini version of your engine. LOL. If I get my setup done before you get around to it, you can come take a look at the results of my custom Y pipe and see what you think.

InfernalVortex

iTrader: (4)

I figure with shorties you're not paying for performance as much as you're paying for ground clearance.

But that's the exact same thing I went through, and I just said screw it. I had a whole exhaust system, LTs and duals, on the car for less than the price of uncoated Hooker shorties by the time I was done.

Dyno Don

iTrader: (7)

My Y-pipe installed:

1989GTATransAm

iTrader: (3)

Dyno Don makes a great exhaust system. I'm running it on my car and I know the exhaust system will not be holding me back in my quest for more horsepower.

89formula350b2l

iTrader: (11)

that would be great! I'm sure you would have it done before me bc i am still paying a transmission off right now..

InfernalVortex

iTrader: (4)

Man, if I had gone shorties I definitely would have done that. It looks great!

89formula350b2l

iTrader: (11)

This guy isnt 14.00 but on a stock 305 here is one members results...https://www.thirdgen.org/forums/thir...nce-again.html