Tunnel ram, 660 center squirters hard to tune ?

[69 N.O.X. RATT]

Looking at a Weiand tunnel ram with dual 660's opinions on streetability?

[norvalwilhelm]

John I am running dual 850 double pumpers on the street without a problem. I did have to work alot on the carbs but once dialed in I get 14.4 mpg around town, never loads up, starts right away and runs cleanly.

[69 N.O.X. RATT]

Thanks Norval. Have any experiance with the 660 center squirters specifically, or a tunnel ram.

Getting cold up there yet ?

[427Hotrod]

Wow..this brings back memories.....

I ran 660 center squirters on a Weiand tunnel ram many years ago on a 396/375 with an L-88 cam in a Pro Street '68 Nova. It was a high 10 sec car with a 4 speed, 15x33.5's and 5.86 gears. Lots of wheelies.

They work very well with a little tweeking. The biggest issue for the street is they are a "1 to 1" carb, where all four barrels open at the same time. Great at the track, a little tricky on the street with all 8 opening at once. What I did was grind out the "opening ramp" on the lingage arm (it's a little different than usual) to delay secondary actuation until you really stomped it. That helped a lot on driveability.

Then you go through the normal idle circuit tweeks as needed depending on cam and vacuum.

Past that, they were great. The Weiand I had had a divider down the middle which sorta made it more like a dual plane and made plenum seem smaller.

The other trick for me was to run ungodly advance on the street. I'm talking 55* in cruise mode. I was using a basic dual point dist. so I emplyed the old Grumpy Jenkins trick of wiring the second set of points act as a timing retard. As you increase dwell you retard timing....so on the street you run around on the one set of points with lots of timing, then as you grabbed 2nd gear you flipped a toggle switch by shifter to bring in second set of points. This increased dwell drastically and retarded timing.

Of course these days you do all of this with a timing computer...but I was poor and this method worked fine!


JIM

[69 N.O.X. RATT]

HHMmmm, sounds like some stuff I may need to brush up on to make it work. 55* of timing, wow. What would be the modern day way of doing things with a 6al? Is there another carb set up you would prefer Jim?

[gkull]

I had the Weiand large runner tunnel ram with 660's also. IMO they were more for WOT running or at least you had to keep the rpm up. I must not be as good a tuner as Jim because after a year or two I came across two holley 450 cfm four barrels. So for cruising and just driving around I used the 450's and race days I threw on the 660's.

It was also on a small block.

[427Hotrod]

You could add on any of the variations of MSD or whoever's timing computers with a locked out dist or a crank trigger and make it do anything you want. They are in the $200 range I think for just the computer. Otherwise you could just add a basic timing retard to be activated with a switch manually or on the shift linkage. The 55* thing basically just made it much more responsive in "street mode", kind of like having vacuum advance for cruising. You could just flip it off and be back to 40 total or so for running it.

The 660's are definitely race carbs. They are very responsive and work very well. But they do take tweeking for street use. I used them because I got a good deal on them and made do with what I had. But they would sit and idle forever and never load up or anything. I would imagine a set of 750DP's would be easier to tune for street use though. I had tons of gear to help cover up any flat spots in street driving.


JIM

[norvalwilhelm]

I run 43 degrees of timming and can adjust it from within the car but it seems to like it there. I have a msd boost computer pulling timing out when the boost comes on.
I removed the 4.11 gears and replace the original 3.08 and have no problems with only flat spots anywhere. That could be the torque of the blower but the carbs themselves seems to really work. I do have holes drilled in all throttle plates and .015 wires in all idle circuits.

[gkull]

I keep all my old Chevy High performance mags. I was just rereading an article about whether to tunnel ram or not. Dec. 00 issue. On stroker small block they did the best with a single 1020 cfm competion fuel systems carb four barrel on a single plane. Forget the 650 - 750 myth about small blocks

The secret was in the fuel delivery of the downleg style boosters. Then they went to 1820 cfm of tunnel ram and it delivered 11.7 more foot pounds from 3500 - 7500