Intake runners by SLP anyone?

[Alfonso Gomez]

I just saw the website for A+Corvettes (ACORVETTES.COM). They offer polished intake runners complete with gaskets for $309.95. These intake runners have been siamesed and supposedly deliver a higher volume of air to the plenum. The advertised increase in HP is about 20. They don't mention if porting the plenum is required. My questions are: Will these runners work in a basically stock engine? My 87 Coupe has the usual bolt ons only (KN, cut lid, Hypertech thermomaster chip, TB coolant bypassed, TB airfoil, cut back spark plug electrodes), and no internal mods. I am planning on upgrading my exhaust in the near future with free-flowing mufflers or eliminators. Also, I eliminated the pre-cats. Anyone has any experience with SLP runners? Any help will be appreciated.

 

[JT ZR-Won]

A friend of mine ran the siamesed runners on his highly modified '85. If I remember correctly, he ordered them from Summit Racing for around $270. I don't know if siamesed runners alone will give you any improvement. The new runners will be calling for more air and your stock throttle body can only bring in so much and then your stock manifold will still be choking. If some motor work like heads and cam are in your future, I would probably do that first and then modify the entire intake system later. One thing kind of leads to another though because then you'll benefit from a larger fuel pump. Just my .02

Jay

 

[Mad-Mic]

SLP runners are direct bolt on's. You won't see the 20 hp increase just from the runnres IMO. do yourself a favor and port the plenum atleast! if you can get the largemouth base also.

i am buying a full TPI intake from a friend for 400 bucks. edlebrock large mouth base, SLP runners, and ported plenum. all ported ready to go with a 52 mm or 58 mm TB.

do your self a favor and atleast port the plenum especially if you want to upgrade to the 52 mm TB. the stock plenum will not fit a 52 mm TB. it is strictly set up for the 48 mm TB. if you do not have the 52 mm TB port the runner side of the plenum. (for now) since you can match the porting with out guessing. use some kind of soft wax or a puddy compound and push it on the end of the runner and push it onto the plenum. what you get is a nice flat surface of the edge of the "open hole" and where the bubble starts is the part that needs to be ported. make sure when you pull apart that the wax stays on the plenum side. cut the bubble part off with an exacto knife then take a magic marker and mark the part that you just cut away and that will be your template.

OR take a heavy wet magic marker or paint stick marker and paint the Runner side and press it onto the plenum and that will give you a template of what needs to be cut away also.

there is guys with stock TPI setups that are running high 12's on stock motors with stock TB's and stock cams. basically motors never been opened! my friend has an 89 vette with no precats, (new front Y pipe) gutted cat, and muffler eliminators with a new rear Y pipe with a 2800 stall with the 3.07 gear running 13.1's at 104 mph. other mods are the cheap basic "freebies" like the TB bypass, cut airlid, K&N filter, descreened MAF and airfoil. thats basically it. stock chip on BFG DR's.

TPI's can run good if tuned good. just takes time and patience. my goal is run the modded TPI setup that i am buying with free flow exhaust, stall converter, transgo shift kit, ZZ409 cam, Roller Rockers, Roller Lifters, 52 mm TB, reworked stock aluminum 2.02 int 1.60 exh heads all ported and polished on a 2.59 gear and hitting mid 12's. if i can get the car going that fast natually exhasperated i'd be really happy.

 

[Edmond]

Alfonso,

If you're going to do the intake runners, you may as well do the intake manifold as well. I just read in my Lingenfelter book that GM was going to do away with the 350 and stick with the 305 but decided at the last minute to keep the 350. What am I saying? I'm saying that our L98 intake manifolds were designed for the 305 motor and we all know the performance differences between the 350 and the 305.

 

[8388]

Here's the deal. I've done this many times with various different runner/plenum/intake combos. If you want to get the most out of that type of combination, just take your factory intake (instead of buying an aftermarket piece), along with a pair of Accell cast runners, and send them to extrude hone.The factory opening size is about 1 1/2" you can safely enlarge the ports to 1 3/4" Both the runners and intake ports will match perfectly, the process has been proven to increase air flow, then port the plenum to the same diameter as the runners your self. Also on the plenum, right behind where the throttle body bolts on the floor of the plenum you'll see a two humps that rise off the floor, those need to be ground down as well.