old school tunnel ram and carbs question

[Plowman]

Unfortunately, I was in the ER and just got released. I thought about this thread while I was in there and I'm glad to reply. The liquid line in the metering block is set up for 8 cylinders, so by having 2 1850s on there, there will be enough liquid to feed 16 cylinders. By restricting the metering blocks to only feed 4 cylinders each, you have 8 cylinders being fed and idle will not be super rich-very streetable.
The vacuum secondardies will work fine by themselves. They are adjustable by changing the springs in them.
If you have more questions, maybe I could post a picture of them.

[budnate]

a question..when we buy these so called matched tunnel ram holleys with the kit like from Summit are they not metered correctly..I was getting a good handle on this until the last few posts...

Thnx Bud

[whitetop]

Bud
The "matched" carbs from Summit/Jegs do not have anything special done to them. What Summit or Jegs mean by matched is they are the same part number ..and I'm being serious.

Plowman, I did not have to change the springs in my vacuum secondaries but in my friends street rod we did experiment with various springs. You mention you can run the vacuum secondaries by themselves(meaning without the vacuum balance kit). I found my car ran much better with the vacuum balance kit-because both secondaries open and close at the same time. I have yet to talk with someone who's engine ran worse with them. Of course everybodies setup is different...and some people just get lucky. I've talked to some people who took 450 holleys out of the box and they ran perfectly with no tuning whatsoever. Some people I talked with changed just about 3/4 of the components on the carbs and they still would not run right.

You talk about blocking metering plates etc to decrease fuel flow richness. I did that by running small 390's. I don't think my small 289 with metered down 600's would have run as good as the 390's.

[rat tuned]

has anyone ran a 6,000 rpm oval port big block with 450 holley's? it would seem to me that 900 cfm would still be plenty. i suppose the 1200 vacuum carbs would work as the carbs would deliver what the engine needed. i'm curious how my 454 oval port would respond as it has a 10" converter and 4.10 gears. i know i like the 450 carbs. mike

[whitetop]

There was a '66 Chevelle in Car Craft in late '80's that ran 450's and the guy said they ran good.

450's would be fine for street cruising in a 454.

[Plowman]

No argument with the balance tube Whitetop. They will certainly make the transition of the secondaries opening smoother. It should not influence the way they close since they close mechanically.

To clarify the liquid line mod, it is not changine the fuel pressure to the carbs, but restricting the fuel flow through the metering block circuits. If you remove your front fuel bowl and then take the metering block out and look on the back side that faces the carb body you will see the liquid line. It can eaily be identified by the only pair of small circuits (holes) which are side by side. One pair on the right and one on the left. It is towards the bottom of the block.

Restricting the liquid line is a tune I like to do on the popular 1850 600 cfm carbs. I did run a pair of 390's on a X-Rammed 327 with the 327/350hp cam. When we swapped them out for a pair of 600's I modified there was a noticable improvement in drivability on the street and ET at the strip. I'm not trying to say it would improve on every setup. I did have better result with 600's over stock 390's on the cars I tuned.

The old 4295 Holley's that were the compliment to the Z28 crossram were 585cfm each and is a lot closer to 600 than 450 is. I think 'ol Smokey U knew a little more about carbs than I do and I'll take his professional opinion that that is the best setup for a little 302.

Summit and Jeggs sell their popular multible carbs kits with smaller carbs than that- so it certainly can work either way. Some like to use smaller carbs, I like to use bigger ones.

I would encourage Musclcar to try and mod the 1850's he has and see what he thinks.

[budnate]

hey Plowman can you show me a pic of how you like to restrict the fuel on the block...it makes perfect sense this is why we have such a hard time with these at idle on the street...whitetop I kinda figured you were going to say that about the matched carbs..."and this complete set-up comes with our special matched tunnel-ram holleys".. remind me to take summit off the christmas card list for next year...

Bud.