Cast Iron intake question
 

I have an intake that I've traced the casting number to a 1972 engine. It's a run of the mill 4bbl intake casting #485912. I've heard that some early intakes have very good flow numbers similar to or better than an Edelbrock performer. How does this one stack up vs. a performer? I'm thinking of building a mild 455 with 6X heads.

FWIW, I'm building the same combo as you and from what I've read here, I'll be planting my '70 intake back on. It gives the stock look, and performs very well from what the experts have said.

Here's a link to a test done by SD performance with different intakes.

http://www.sdperformance.com/newsStory.php?newsID=44

I think that the stock intake does pretty well in a mild build. It comes down to what the rest of your combo looks like.

I'm building the same basic set up, except with a 400 and #13 heads. My intake is a '70 modified to remove both the water crossover and the heat crossover. The plenum and carb mount face will remain stock for now. My heads are ported to Jim Hand's specs (as well as I could) and the intake and head ports matched to the standard Felpro gasket.

I have a Performer on the bench but won't be putting it on.

Stewart

Hmm...I have to admit the brand I'm most familiar with is Oldsmobile. I can tell you that the stock iron Olds intakes suck compared to the aluminum ones. Doesn't seem to be the case for Pontiac. I'll probably reuse the stock iron intake instead of spending money on an aftermarket one. Afterall, it has no EGR and the divorced choke spring still seems operational.

The stock cast-iron Pontiac piece is damn good, especially with minimal modifications. Simply ensure that its runner dimensions match those of the cylinder head intake ports, and then carry that size towards the plenum a few inches to ensure consistent cross-sectional area throughout the entire intake tract.

There's nothing wrong with an Edelbrock Performer in an application such as yours, but I'd suggest installing one only if you're looking run an aluminum intake for appearance sake, or for its dual-pattern carb flange. The gains are otherwise neglible.

I agree with Rocky and have found improvement with the stock intake myself. The 400 in my 71 GTO with the Lunati BMII (.490 lift,292 adv. [email protected], 110 lobe seperation, 104 IC) likes the stock better with my unmodified 670 heads than it did the Performer or my Torker, especially with a 4 speed. 60ft times dropped to the best the car ever did after going with a stocker, 1.80 compared to a best of 1.92 with the Torker and 1.95-2.01 with the Performer. Alot stronger in the midrange, up to my shift point of 5200. Go with the stock, better choice overall, especially on the street.