SBF 289/302 Weber CROSSRAM! Is it true?

[Anthony]

Originally Posted by vintagewebers

Here is a photo of the 58mm crossram I own with a set of sidedrafts. It's not as pretty as it could be but i'm still doing restoration work on the carbs. I don't know about you, but to me that is the ultimate sex appeal for the SBF.

just curious, it's hard to see, but do the intake runners decrease in cross sectional area as they start from the carb base and pass to the opposite side of the intake, with most runners being sandwiched between two other runners? Or do the runners have equal cross sectional area the entire length?

Originally Posted by What'saCobra?

Further, clearly a 58MM unit is way too much for a 289, .

I thought that somebody said that the weber 58mm downdrafts were developed for ford 289 "indy" engines, and I believe that several magazines in the early 1960's spotlighted these carbs/indy engines. obviously, I would think Indy engines run at WOT at max rpms, most of the time, at least at the Indy 500.

Weber has a chart that recommends a certain size carb based on engine size as well as max rpms. The higher rpm you run an engine, the bigger size weber carb you need.

[What'saCobra?]

Ant
The Indy '289' is another whole kettle of fishes. Of course, it was really an all aly 255 in2 DOHC and turned perhaps 8000+rpm in good fettle. The 255 was also used in the initial GT40 MKI's, but was replaced rather quickly with 'normal' 289's because of poor torque coming out of corners, wacko costs and fussy to maintain...

That engine, no normal SBF, was no streeter or road racer with the 58's. If the rpm dropped under 4500 it was in big trouble. But, it could draw enough from 58's to work nicely at high rpm on an oval as long as speeds didn't get too slow.

My guess is that a modern stroker W with the best hi-flow heads available would 'use' the 58's to better effect, but it will take some work to get them to transition nicely and come off the line without popping/leaning or loading plugs at idle. Those sewer pipes aren't going to like just-off-idle air flows and will even make starting a pain on a small displacement engine.

Given that someone could do that work, wouldn't they be great lookin'?