Camshaft?
 

In reference to a 427 FE/webers. Can a camshaft be selected to provide a lumpy idle?

Not really

To the point, but I'm sure that will be the overall consensus. You can't have your cake and eat it too.

Thanks,
Tom

You can un-synchronize the Weber's , even slightly.

Voila , instant lumpy idle.

Z.

Cam selection
 

Look into COMP "thumper" cams.

You can not run the Thumper cams with Webers. Webers are very finicky when it comes to lobe separation angle (LSA) and duration and overlap. Large lumpy cams cause reversion which disrupts the flow in individual runner (IR) induction systems.

Thumper cams are junk and were made for the sound, not performance

Amen Bill on the Thumpr cams......especially in a street driven application where you need vacuum and a clean idle.

Webers look good, but that's about where it ends....

Brent
Why don't you like Webers?

We don't have that much time....;)

I know everybody has different positions on cams and every other part on engines, i run a comp thumper cam on mine and it made 547hp on a 408 cleveland, it also idles at 850-900rpms on QT pump gas;). I hope i don't jinks myself for saying this but the engine runs and sounds great!

In and of themselves, the Thumpr cams are not inherently evil....

They cross the line when they are paired up with engines that need to produce vacuum for accessories, or in situations where there is an emissions testing program.

The way that they work is that they have a very large duration split, usually 14 degrees or so. That's combined with a pretty tight LSA...usually 107. They do well in a raw street strip engine because a tight LSA generally produces a bit more torque. The lobe designs are also on the lazy side, so they're going to be easy on parts and quiet. However, that tight LSA and that large duration split is going to create a huge amount of overlap. That overlap is what makes the sound, but it also insures that both valves are going to be open at the same time for a longer period. That can facilitate reversion which can cause problems of its own.

If you have to have an evil sound, I suppose they fit the bill. However, IMO, there are better choices for a street cam, especially when you're pushing power brakes, worried about gas mileage (hahaha), or have to go through stringent emissions testing.

The people that respond to the questions are great, informative, very educated on the subject.

Business wise, I would LOVE to have guys come in with 4 Weber 48 IDA's on their American V-8 for me to tune and / or install. You have a customer that couldn't or wouldn't spend the time to learn how to deal with them, and you know he's going to pick up a completely better running car than he dropped off when you are finished. As long as you are upfront about the cost involved and don't get roped in to a specific number of hours of labor, the shop should be $$$ ahead at the end of the day.

As a professional motorcycle mechanic, I learned on the motorcycles of the '60's & '70's including the inline 6 cylinder, 6 carbs, Honda CBX 1000 circa 1979. Many of those early Japanese superbikes had no accelerator pump circuit in the carb system that could be "used" to cover up poor tuning by the technician. They had to be right. Weber's are a piece of cake in comparison.

As far as the Weber's only "looking good" goes, the torque increase is phenomal, and a little ol HiPo 289 needs all the extra torque it can get. Not to mention the 41 extra HP at the peak rpm.. Anyone who can't get a decent boost in peak HP with a set of Weber's vs. anybody's 4 barrel, just hasn't got them figured out yet.

PS, Blykins, thanks for getting those Ferrea big valves for me. So far so good, I'm hitting 6,500 rpm every chance I get.

Z.

talos,

Either the dual carb setup or the Webers will give a wow factor. Due to the things I've described, you probably won't be able to end up with a street oriented engine, wild sound, and Webers. However, you can go with the dual carb intake and put a little thump in the engine. You will probably lose some hp by going with the dual carb intake over the Weber setup.

zrayr,

You're very welcome on the valves. Good pieces....

On the Weber setup, I think I'll have to disagree with you. If you compare apples to apples, a correctly chosen and tuned single carb intake setup will make more hp, and I can play with the camshaft to easily win with the torque.

I've seen lots of comparisons between Webers and a regular setup, but it's always been a very biased comparison...i.e. a tuned Weber setup vs. a low quality dual plane intake...or a tuned Weber setup vs. an intake with an incorrectly sized carburetor.

I agree that a Hipo 289 will be low in torque, but there are many ways to get around that. :)

In my limited experience, the K code engine always did better power wise with more carbs. Two were better the one , the three duces worked better than two,4 barrels, and the Weber's were at the top,of the heap, until you started with the vintage Paxtons,etc.

However, I don't have any experience with aftermarket intakes, or modern carbs.

in comparison with my last GT350, with its Holley 715 &'Cobra Hi-Rise manifold, the Weber equipted K code was stronger all the way, from 2000 rpm to 6,500. And it made 41 more HP than the K code did before the Weber installation. I won't set any records, or set the world on fire with this car, but I got the most out of it without going modern, which was my goal.

As my dad used to say, here's more than one way to skin a cat, (although I never saw him skin one).

Z

I'm sure the Webers were triumphant when compared to the other factory combos of the time, but they would be found lacking in comparison to the modern stuff.

I just looked up a few posts and saw where Rick Parker "liked" your reply. That really makes me sad.

Us Weber nuts have to stick together.

Life's too short, so Cheer up & I'll buy you a beer.

PS. Correction: I have used one semi-modern carb, I put a Holley Street HP 650 in my '66 GT350 w/ Vintage Paxton. I liked the replaceable air bleeds, no air horn that need milling off, etc.. I did have to fabricate an air diffuser to get the last 20% from the Paxton @ high rpm.

Z