I do not want siamese intake as someone in thirdgen, just porting is as much I can. I read somewhere that stock intake manifold has 1.47 inch (37 mm) round intakes. It is possible to port them to 1.6 inches (41 mm)?
Jerry

 

i just sold a GM manifold i ported to a forum member this week, as to your question, yes at the mouth but hard to do in the middle. you'll use up quite a few cartrage rolls doing the porting. most of the flow increase will come from de-burring the mouth and increasing the radius to give the air a better line of sight. at the manifold exit work the fuel injector bosses flush with the metal. they protrude down stock & restrict flow. the exits also can be enlarged to better fit the stock heads & keep turbulance to a minimum. that's basically how it's done, rather than spend $40 + 5-10hrs of your time porting it. i'd lean tward the big mouth base on the used market. wasn't a accel big mouth going for $250 on here? i managed to get a edelbrock base for $150 off ebay. also i've heard from more than one person {gasp} accel has a better & bigger base than edelbrock..that's something you'll never hear me say about any other part as i really am NOT a fan of anything accel makes. however it could be true on the base, i spent about 5hrs on my edelbrock base to get it how i wanted it match & flow wise. also..note to forum, never buy SLP runners unless you plan on porting them. out of every aftermarket runner i've seen they have the worst port shape, a rough texture inside and generally need 5-8hrs on the porting bench before they think about rivaling AS&M. however if you do work them, they are great, very thick casting that lends well to porting. p.s. make sure you remove the ridge behind the TB in your plenum and match the exits to the runners.


[Modified by gtsyellow, 2:40 AM 7/6/2002]

 

I know that Vic'89 installed a BM base with stock runners and showed no gain in trap speed.

Then he installed my AS&M LT runners and the combo showed a 15HP gain, based on trap speed.

So porting the base with stock runners will not likely show any gain.

 

thanks
I will do not use stock plenum and runners.
I will start make my own super ram (stainless steel) next week. :yesnod: :D
So I need manifold from 1.47 to 1.6 to mach my SR runners (runners will be at manifold side 1.6 inch).
Just asking about porting manifold because I do not want to broke something (too much porting). Ach, and place when I want do that has CNC machinery too.