I am building a 350 for my 89 Iroc and I am curious about what brand (out of the box)runners people had and how much gains they got.

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89 Iroc 350 TPI,
Forged pistions
Comp Cam .510 lift 230dur
Flowmaster exhaust
Aluminum Heads SOON!!!
MINI RAM SOON!!!!!
stock TPI for now 24# inj

 

AS&M are the most popular, they have both Large tube and siamesed runners, do a search, you'll find lots of info about theese.

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTR, !plenum, 52 TB, MSD 6AL, TPIS level V prom, Superior shift-kit and all the minor mods, a AFR 195 headed 383 in the works!! ready May 2001...
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

 

Yeah, AS&M's.

 

I am pretty sure that AS&Ms are the best, but they are the most costly. What I am planning on doing, is getting a set of the SLP runners for $250 or so and polishing them up myself.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base

 

well SLP is selling their siamese runners for 199.00 at their site. If u go to the TPI department and i believe its page 2,3,4 and theirs this post a guy got that sells SLP runners for that price. I've also heard that AS&M runners are poor quality.

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92' camaro
New 305 block TPI conversion, Flat top pistons,Bore over .30 Forged parts all around,Edelbrock intake,ported plennum,ported corvette alluminum heads, accel cam,52mm throttle bodie, SLP runners Home aid cold air induction, Air foil,ford SVO 19lb injectors,fuel regulator,cloys timing chain, comp alluminum roller rocker arms and pushrods MSD 8.5 mm wires, bosch plattinum plugs, hypertech cap & rotor and coil, Edelbrock TES headers, free flowing catalytic converter and a 3 inch force II flowmaster exhaust system, and a 3 inch cutout,Zoom multi friction clutch, T-5 tranny,billenstien shocks&struts.
Soon to come!!!
Procharger system 12lbs o boost.
New paint job(hawaiin orchid purple)Cast alluminum ZR1 rims w/ 275 tires.
Favorite quote: "where ever u go, there u are"

Other car;
1971 plymouth Duster
Mods:340,edelbrock victor jr. intake, 650 4 barrel holley, heddman headers,40 series dual flowmasters, cold air intake,4:10 gears, just got a new paint job and cragar rims with 315 tires in the back.
:Yeah its not a chevy but damn how many 71' dusters have u seen in the streets.

 

Just curious as to why nobody ever mentions Edelbrock runners. They are 1.70" ID and are of good solid quality. I picked mine up for under $300 ($578 total for the base & runners).

And why does everyone think that the AS&M runners are the best? How much power difference would there be between the "worst" runner design and the "best" runner design? Maybe 10hp at the most?

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'92 RS, ZZ4 10:1 350, Edelbrock 6085 heads, Crane 208/214 467/482 cam, GM/LT4 1.6 roller rockers, Edelbrock Hi-Flow base, runners & 52mm TB, SLP/Jet-Hot 1-5/8" headers, Catco 3" cat, Flowmaster 3" catback, Hughes 2500 stall converter, stock 700R4, Auburn Pro posi w/3.42, 17x9" SS rims w/BFG tires, Medium Quasar Blue w/white SS stripes, 48,000 miles....

[This message has been edited by Scott C (edited April 23, 2001).]

 

I've never heard any quality complaints regarding AS&M runners. I've owned two sets, first the large tubes and now the semi-siamesed. I'd say the quality of both was above the stock runners.

In theory, the AS&M runners are the best because they are made from extruded aluminum. So like the stock runners, they are very smooth internally.

Other aftermarket runners like the Accel, Edelbrock and SLP runners are made from cast aluminum. These runners have rough internal passages compared to extruded aluminum runners.

Does this mean that cast runners are inferior? I have no idea. All I know is, as far as airflow characteristics go, air, plain old air, will flow better through a smooth (extruded) passage. An air/fuel mixture will flow better through a rough (cast) passage.

As far as design benefits - with the LTR's my engine produced a ton of torque but didn't seem to pull beyong 5400-5500 rpm. With the semi-siamesed pieces it revs like mad to 6000. I've never taken the engine past 6K, so I couldn't comment on anything past that point.

A few years ago there was a guy on the board who had the SLP runners. He ported the hell out of them. He had them extrude honed. In the end he ditched them for a set of AS&M's, and said the car was quicker with them.

Anyway, I'll shut up. I say go with AS&M.

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Jed
89 Formula 350

[This message has been edited by Jed (edited April 23, 2001).]

 

Well i just installed a set of SLP ones and they only cost 199.00. Truthfully they definitely gave me a bit of a boost and gave me a better RPM increase over stock. Plus i then ported the **** out of my plenum and its a really nice airflow. And it is true that the inside are gritty like but I heard its actually better to get airflow broken up slightly because it make for a better air/fuel mixture. A buddy of mine ports heads and all that stuff too and he said to even leave my plenum slightly griddy cause the air circulates better that way. I say SLP for the price. But they were a pain in the *** to install for me.

 

Cm87pta: The flaw in that theory is that the TPI plenum, runners, and intake are dry flow. There is no fuel in the air so a rough surface is not needed to keep the fuel particles in suspension. Everything should be smooth right up to the intake port of the head where the fuel is shot in.

 

Just checked out the runners on ASMs site they look very nice but also so exspensive and then you are going to need manifold to go with it. I do not think you will get a big increase with runners alone as stock manifold is so restrictive. Anyone else have comments on ASMs runners and manifold. I was thinking about getting Accel but maybe ASMs better but the price is kinda high.Jed do you have stock cam in your car?

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SLP 1 5/8 Headers,ATR catback exhaust,SLP cold air box,Crane 1:6 roller rockers,Bosch plugs and MSD wires,MSD Coil,Fastchip,Borg Warner 9 bolt 3:27,Corvette Servo,ROH ZS 17X9.5 Goodyear GSC,s 275/40/17

[This message has been edited by Raymond 5.7 89 Formula (edited April 24, 2001).]

 

Like i said your best bet is to get the $199.00 SLP runners take them to a local machine shop do some mild porting $30.00 and u should have a good set. No reason to spend 400.00 for a measly 10 hp. Its all about logic.

 

I have the AS&M's and Edelbrock base and can i say neck snap?

 

Raymond,

When I first installed my AS&M LTR's, I was still using the stock base manifold, a ported plenum, and I had headers and exhaust. Aside from that it was a stock L98. I don't have any hard data. All I can tell you is that the ported plenum and runners went on at the same time and felt like I picked up over 10 hp (can you feel ten hp?). A few days later I raced an LX and came out a bit ahead - I was surprised.

The stock base is a restriction, but I believe that the stock runners are the biggest restriction. You have to remember that the TPI intake was designed to increase torque on the 305 - it was not designed to go on a 350!

Currently I run a Crane 2050 compucam, 1.6 rockers, Edelbrock heads and TPI base, 52mm tb, along with the semi-siamesed runners and a bunch of other stuff that isn't relevant here.

BTW - they are expensive! I bought both my sets used. Try the classifieds first.

SLP runners: 6.625" length, 1.600 port dia.
AND THEY'RE CAST!

AS&M runners: 7.625" length, 1.660 port dia.
Extruded = better flow

IMHO, you get what you pay for.

 

This isn't relevant, just wondering, Jed where are you from on the Island, I'm in Suffolk.

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'89 Camaro RS 6cyl. auto, don't know how much longer I'll have it.
'90 Iroc TPI 305, 5 spd B&M Ripper shifter, hopefully I can rob a bank or something and get more
www.geocities.com/irocnroll90

 

Unfortunately, if ya didn't spring for SLP runners while they were on sale, they are back to their regular price - $249. Mind ya,, that's still 'bout $30 cheaper than Summit sells 'em for.

 

Why does everyone say that the TPI was designed for a 305?? It seems to me that the corvettes got the TPI first and and they never had no 305.
It seems stupid to think that GM designed an intake for a f-body's 305 and then decided to put it in the corvette. It never happens like that, and I don't think it did this time either. Everytime something new comes out it's clearly designed for the vette and then the F-bodys pick it up later.

 

There is absolutely no difference in size between the 305 and 350 TPI intakes. As we all know the system utilizes very long intake runners, designed to increase torque output of the 305. GM wished to do this because they were planning on discontinuing the 350, due to fuel economy and emissions regulations.

At the last minute GM reconsidered and decided not to drop the 350. But they needed a performance port fuel injection intake, and the only one they had was the 305 TPI intake. So they stuck larger injectors in it and put it on the 350. Hence the reason stock L98s produce a ton of torque yet tend to max out before 5000 rpm.

This is also the reason there is a market for semi-siamesed runners, the SuperRam and the Miniram. If the stock runner setup worked well, no one would have sought to change it.

GM does stupid things all the time. Just look where F-body production is headed.

90Iroc, I'm in Suffolk too.

 

If I remember correctly, the last couple of years of the C3 (at least the '80 anyway) a 305 was "standard" in the California version.

The 'Vette didn't always get the goodies or get them first. Case in point, the 409. Not that it would have made a good combo but Chevy's 409 was their strongest powerplant for a few years in the early to mid-sixties.

The '67 SS Camaro had the 350 exclusively for its first model year. The '70 LT-1 was available in the 'Vette and Z-28 at the same time.

The LS-6 (the good one-454-way more potential than the new one) was available in the Chevelle and 'Vette in '70.

In the mid-to-late '70s, Chevy's fastest (and there is a little debate here but the magazines played it up) was the 454 1/2 ton TRUCK.

'Vettes are ok but they haven't always been the top of the regular-everyday production GM food chain (although I sure would like to have one of the two '69 ZL-1 all-aluminum 427 'Vettes).
jms

 

I was thinking of going edelbrock base and runners, now I don't have the money for the as&m's I want to put on better of the 2 slp or edelbrock?