Progressive linkage?

[Fathead Racing]

Step on up.

Ok, I'll bite. Hey Fred, are you soaking any of this up????? Y'all remember ole "60 foot" Fred don't you?? He's the one running 11.68 with "progressive linkage". I think it's time for Fred to try the solid linkage this coming season and make the comparo.

 

[Ronnie Russell]

Fred can try direct if he wants, but I still believe there will be no differance one way or the other.

 

[dq409]

Food for thought....... 409 2-4bbl car. Staged and ready for lights to come down. Manual shift car, gas pedal depressed for 3,000 to 4,000 rpms launch. or A/T car , gas pedal depressed to just short of stall (2000rpm) . Launch time, stomp gas pedal to floor. Which linkage is best for launch? Answer is -- either!!! Either linkage will produce 8 bbls WOT instantly. The differance inthe two would be measured in thousandths of a sec. No differance when mechanics of the car (suspension, etc.) are taken into consideration. Those who prefer progressive linkage need not change just for drag racing. The only differance in the two is the fun factor. And also if you look at the front carb activity during normal city driving with progressive linkage you will be surprised at how much the front primaries are used. To keep front carb. from being used in normal driving , you would have to creep everywhere you go. AS said before , this is just food for thought. How long does it take to stomp gas pedal to floor,(especially when it is already at half throttle)? The blink on an eye. Maybe .010 of a sec. I think less.

Ray ,, Before you give "60 Foot Fred" any grief read the above again !:takethat
The difference will NOT be launching from a good race RPM ,, but the crisp crack of the throttle on the street !!

Do we have to come out there and clean the snow from your ears ???


Seriously Ray,, Get a good adjustable progressive setup and enjoy your dual quads both ways !!!! ,,dq

 

[Fathead Racing]

Oh--------------Ok!:evil

 

[MRHP]

Throttle response

Crisp throttle response on the street.I could not have put it better my self DQ. Would be a shame to come off a stoplight with a " lazy progressive linkage ". If the progressive linkage is so conducive to power and performance, how come all racers don't use it? Progressive linkage is easier to tune, but that is where the benefit ends. I guarantee if you switch back and forth between the two, you will have some tuning issues to contend with. Good luck with your choice. Brian

 

[SS425HP]

Progressive or direct??????????

When I was racing my original 63, I drove it on the street and at the track. Ran progressive on the street, and hooked it up straight at the track. Was the thing to do. Don't ask me why. We all did it. I've been racing this car with it progressive. Hold 4-4.5 on the line, nail it and go. I don't know that you could tell any difference with it hooked up direct. When you slap your foot down, they both hit WOT at the same time, hooked up either way. I don't remember ever having to retune for hooking up direct. The carbs are WOT all the way to the end. Same as if hooked progressive. Same amount of fuel through the squirters. I really don't think it makes any difference. Only reason it's crisper direct, is you are moving both carbs at the same time, but less travel to get the same result. Like 1/4 throttle direct compared to 1/2 throttle progressive.

Just my opinion. Been wrong before, might be wrong again. But I don't think so. I think Ronnie is right, except I doubt there would be even .010 difference. Maybe .001 if any at all.

I do think progressive runs cleaner on the street. Cheaper, too. But, then again, it takes a certain amount of gas to get a certain speed. One carb or two shouldn't make any difference if both are jetted the same. Just less travel with 2 hooked together direct.

Like I said. This is my opinion.

Fred

 

[Ronnie Russell]

You are right on the money Fred, at least as far as I am concerned. The reason throttle response is better with direct is that both sets of primaries opening at once. To get the same response with progressive requires much more pedal travel. It is really a non-issue, but it was interesting to hear differant opinions. I used the number .010 because I needed some kind of comparison. You may have noticed that I added "I think less". But .001? Even with your reputation of having a lightning fast right foot, it might take longer. How about .005 ?? Wonder if Ray knew the discussion he would cause by asking a simple question? I think he did, he already knew the answers, he just wanted to shake cages!!!!!

 

[gearhead409]

Fred, i like your comments. my blower motor runs fine with both carbs hooked together and gets good gas mileage like JimKs engine. i have had the same results as Fred with my stock engines. the only thing i can see with them hooked together would be if you're driving around town at low speed, you might be in the off idle circuits alot and cause a rich condition. off idle is a little fat in most carbs.

 

[SS425HP]

You are right on the money Fred, at least as far as I am concerned. The reason throttle response is better with direct is that both sets of primaries opening at once. To get the same response with progressive requires much more pedal travel. It is really a non-issue, but it was interesting to hear differant opinions. I used the number .010 because I needed some kind of comparison. You may have noticed that I added "I think less". But .001? Even with your reputation of having a lightning fast right foot, it might take longer. How about .005 ?? Wonder if Ray knew the discussion he would cause by asking a simple question? I think he did, he already knew the answers, he just wanted to shake cages!!!!!

Ray wouldn't do that Not the Ray we know

Hey, the snow gets deep up there, and cabin fever sets in. Poor Marcia gets stuck at home with him

But, the guy gets a lot of mileage from that 60 Chev. Does it like we used to do. Drive it to the track, and runs good. Drives it home. Got to give him credit for that.

But, he is a little whackybang

Fred

 

[4onthefloor]

Great discussion....I would assume with the right pieces you could easily make the factory progressive direct right ? Anyone tried it and if so what did you use ?

 

[jester]

That is it, In the spring I'm putting them together

 

[SS425HP]

adjusting linkage.

Great discussion....I would assume with the right pieces you could easily make the factory progressive direct right ? Anyone tried it and if so what did you use ?

Just move the linkage on the front carb to the top hole. You have to lengthen or shorten the rod a little, but the adjustment you need is there. No problem. Look at the picture near the beginning. Go to the top hole on front carb, and adjust the rod so it's pulling the front carb open when the rear is opening. They will open at the same rate if the linkage is in holes the same distance from the throttle shaft .

Fred

 

[4onthefloor]

Perfect....thanks.

 

[Fathead Racing]

Wonder if Ray knew the discussion he would cause by asking a simple question? I think he did, he already knew the answers, he just wanted to shake cages!!!!![/QUOTE]


Ronnie, you give me to much credit, I'm not that clever! No doubt that hooking the carbs solid will give you more acceleration away from the light with part throttle Drivability will be much better with progressive linkage around town and I still like to go Mustang hunting on the street. :takethat I'm pretty sure that gas milage will be better also. Fred, Marcia is "tied" up right now or she would thank you for your concern. Thing is, with the right progressive linkage setup you can have your cake and eat it too!

 

[Ronnie Russell]

Hey Ray,,, Did you ever get any difinitive answer about the hardened seats? Just curious if you recieved a " do this or dont do that" information from the experts. Thanks

 

[Fathead Racing]

Ronnie, my machine shop guy called Tony Shaffer and he would not divulge any info on the part #s or machining to place hardened exhaust valve seats in the 690 heads. My machine shop guy says Tony made a big deal out of it???? Any way, A well respected 09 race type guy that is a "true loyal member here" said that installing bigger SS exhaust valves is the way to go. That is what we are going to do. Now is the chance to install a narrower valve stem for reduced weight also . I have decided to use my own methods and experience ( in the quest for added HP. I have always built and picked all the parts for my engines, why stop now??? Can't understand why someone would not share information about this orphan engine ??? It's not like I'm trying to corner the market in 690 head design here in NE Ohio .

 

[Ronnie Russell]

Thanks Ray, My daddy taught me , if I cant say good about somebody, then dont say anything at all. I sure would like to say something right now!! The "true, loyal member" is the guy I would trust. The other guy can keep his knowledge. Good luck with the 690s. I know it will turn out great.

 

[MRHP]

Valve size

I have the stainless valves in my 583 heads. The intake are 2.250 and I don't recall the exhaust. I do not have the hardened seats and I never give it a second thought. Run the snot out of it and have fun! Brian

 

[4onthefloor]

What if you don't know which true and loyal member you guys are talking about ?

 

[gearhead409]

Ray, your choice on using larger exhaust valves is a good one. be careful with cyl. wall clearance on the exhaust valve if you are using a cam with alot of lift. after you get the valves installed i would put one head on an empty block, look up the cyl. bore with the valve off the seat the same amount as your cam lift and see where you're at before bolting them on your good engine. ( i wonder if Fred is getting nervous about this yet? )