Progress Thread At the end of my tether!

1963_Falcon_4dr_wagon said:

I read a discussion the other day on aftermarket intake manifolds on stock small block Fords. The conclusion was that the stock Ford 4 barrel manifold will out perform an aftermarket manifold on a stock SBF. I remember installing a Performer intake on a stock 302. It was a waste of money plus the intake manifold and head surfaces were not parallel.

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That engine is essentially stock, with only a camshaft upgrade. Look at the port size/flow difference between stock and all of the the aftermarket intakes (feel free to ignore the tunnel rams since we're talking street cars here).

Now, when you get down to the dyno results chart, THAT is where you're going to find the real gold.

The stock 4bbl intake from Ford (assuming either early, pre-EGR, or the mid 80s manifold with EGR) is a surprisingly good piece performance-wise, and for someone dealing with California emissions, the mid 80s aluminum 4-bbl manifold with EGR is 100% what I'd recommend all day. Even the old iron pig from the 60s and early 70s isn't horrible, especially when you look at low end torque, but it's heavy, and holds in more heat than an aluminum manifold. However, take a look at 3000rpm or so. Notice how the stocker starts losing it's low-end advantage to the Edelbrock Performer? Take a look at the other dual-plane intakes, the same trade-off happens in the same area, give or take a few hundred RPM.

If throwing a Performer on your 302 cost you power/drivability, it probably had a lot to do with the overall gearing. Tire size, rear gear ratio, and transmission ratios all have every bit to do with your acceleration and drivability. If you don't match everything from one end of the car to the other, the car won't perform well.

Take my Mustang II for example. It runs a set of heavily modified heads, a slightly rowdy camshaft, roller rockers, and a ported Performer RPM manifold. If it wasn't for the 3300rpm stall torque converter and the 4.11 rear gears, it'd fall on it's ass off the line, in spite of the fact that the engine makes fantastic power for an old iron-headed relic.

I put an Edelbrock Performer 289 manifold on a stock 302 years ago as well, luckily I was upgrading from 2bbl to 4bbl, so I had a significant improvement in power overall, but it was still a little sluggish off the line, possibly a little more so. Why? I killed the low-end torque and it had 2.79 rear gears and a stock converter in it's C4 transmission.

You've got to look at the whole package.