Well, I picked up some siamesed runners off eBay, and they are labelled as GMPP. At the risk of sounding too newbie-

Are these the same as SLP runners? They look very similar.

Also, I never realized that one set of runners on each side is siamesed all the way down, while the other is only connected by about 3" of depth at the top... On the surface I would think this would be a power balance (or lack thereof) issue, but it's been a while since I've worked with a GM smallblock.

Are these runners decent?

Also, I got the 85-88 runners, so I believe I need the cold start injector blockoff to use them on my 90 Formula. Where would I be able to get the kit?

Thanks for any info!!!

Matthew A. Green --- mattgreen(at)msquaredracing(dot)com
M"squared" Racing! --- http://www.msquaredracing.com/
85 Shelby Charger- 260hp, no waiting!
87 GLHS #314
90 Formula 350- I think I'll have a V8!
98 P-Neon SOHC- ACR wanna-be
01 Ram Off-road- Something has to tow all this stuff!

 

I didnt know GM made better than stock runners.

 

GM Part # 12341415

Are these things really that rare?


Matthew A. Green --- mattgreen(at)msquaredracing(dot)com
M"squared" Racing! --- http://www.msquaredracing.com/
85 Shelby Charger- 260hp, no waiting!
87 GLHS #314
90 Formula 350- I think I'll have a V8!
98 P-Neon SOHC- ACR wanna-be
01 Ram Off-road- Something has to tow all this stuff!

 

gmpartsdirect.com has no listing for them, so i dont know. Go to a dealer and inquire.

 

Here's a pic of them...

Any thoughts?

{hmmm, I thought I posted a pic}

 

Trying the pic again....



Or go to
http://www.msquaredracing.com/glhs31...d/gmppruns.jpg
if it doesn't show up...

 

Yes, those are SLP runners. Way back in the day you could buy a new F body and have the dealer install the SLP performance package (runners, headers, catback, PROM, CAI) or you could buy it separately out of the GMPP catalog. They all had GM part numbers but were still made by SLP.

 

Yeah, what he said. You could even have the installation of those parts financed into the deal when you bought the car new

 

That seems kind of weird that one side on each runner is siamesed all the way and the other is not. Did SLP actually make those that way? You would think the air flow would definitely be unbalanced somehow between cylinders!

 

Thier the old school slp runners, before they made the newer style where all 4 inlets are partially siamesed.

 

Did the SLP package deliver the goods for the extra money back then? I was still playing with little plastic soldiers and riding my bike back then...

So does anyone remember if it made quite a difference? I can't imagine the prom to be to much better than some off the shelf junk.

 

If you can find the Aug 88 issue of 'Hot Rod' magazine, they did a test on an L98 IROC using the whole SLP package. I'm going completely off memory, but they knocked off almost a second in the quarter mile and the motor breathed better over the 4800 RPM "wall". I believe it ran like a 14.0x in the end. Back then that was pretty good, considering SLP's goal was to reduce quarter mile times by a second, stay 50 state emissions legal, and not reduce fuel economy.

 

http://sethirdgen.org/performance.htm#gta91slp

 

Not to shabby at all. A nice base to start with actually, 14.0x
=9