BILLY D

Is it possible to port a stock 91 intake to flow like a big mouth intake and is it worth it? I would like to go with large tube runners at some point and wondered if a ported stock intake would work just as good as a large mouth or would I loose a little? Is it worth the difference? I want to keep the car looking stock but would like some more power as we all do. I also heard the Big mouth is about 1/4 inch shorter than stock on the ends. Anyone have sealing problems?

THANKS
BILLY

vader86

If you ported it all the way, you might get it or get close, but then you will have no upwards potential like the BigMouth does. Save your money for a bigmouth.

Aaron's 87

My fully ported Edelbrock base and runners flowed 8% better than my fully ported stock base and runners. The aftermarket ones are not worth the money in my opinion. The aftermarket ones do have more meat if you just plan on hogging them out.

BILLY D

Arron: Did your stock base use the large tube runners or stock runners when you did your flow measurements? How much does it cost to port a stock base?

Aaron's 87

The 8% gain was the ported Edelbrock base and runners versus the ported stock base and runners. The Edelbrock runners are a couple tenths of an inch bigger than the stock runners. Porting will depend on who does it and how much they charge. You can do it yourself in a day, but it's good to know what you're doing, or you can do more harm than good.

VetteRacer282

Manifold yes you can port it. Runners I dont beleive so because they are smaller outer diameter as well.

Dont let anyone tell you otherwise on the manifold, the meats there, and aftermarket manifold cant offer any more meat because the runner holes and head holes have to be in the same place...
Matt

BBA

Not exactly the case Matt. The aftermarket big base has physically larger diameter runners. This is the reason a stock HEI distributor will not fit correctly on one. We had to use a small base diameter distributor on the last one I helped install because the number 7 runner interferred with the stock HEI distributor base, it's that much larger.

Phobos84

As far as price of the aftermarket Highflow intakes and runners and them not being worth it I will have to argue. I picked up a new in the box Edelbrock high flow intake and runners from ebay for $430. Thats $200 less then Summit racing. There is a lot of room for porting if you want to invest the time/money. As far as compairing flow numbers of different intakes buy the TPIS book Insider Hints. They have pages and pages of dyno runs with different intakes on it. They don't list the Edelbrock but it is the exact same thing as the TPIS Big mouth. They just slap different names on them in the factory. The tests from TPIS show that a fully ported stock intake made better power in the 1000-1800 rpm range but a non ported High flow intake beat it in every other rpm. They didn't list any ported numbers for the high flow so I don't know what a ported one will do.

Aaron's 87

WOW, they got better numbers from a product they sell?

1MoorTym

In a word, no. Just take a look at the stock base compared to the big mouth, or super ram base and you'll see why. I haven't had any issues with my Accel base, don't think it's any shorter, but didn't measure it either.

BBA

...Which brings up another question...one that had to surface sooner or later:

How would the big mouth compare to the siamesed factory base?