Chevy cross ram tuning.

Just a word of caution on your 450 Holley carbs. If they are the usual later 450 carbs that have mechanical secondaries, but without secondary accelerator pumps, don't waste your time trying to make them work on your crossram! Takes enough tuning to make a crossram work well, and the lack of secondary accelerator pumps makes the 450's a PITA to tune. A better choice is a pair of 600cfm 1850's with vacuum secondaries.
I've tried to get the crappy 450 Holley carbs to work in a couple dual carb scenarios, and eventually got them to work fairly well on my Holley Pro Dominator tunnel ram. But it took a lot of time and more money put into them to get them to work fairly well. Still not great as the gradual transition from primaries to secondaries still has a flat spot, but at least they don't fall on their face under full throttle anymore. It took changing to 50cc accelerator pumps, changing to larger squirters, and messing with jetting, to finally make them perform acceptably for street use.



On my other gasser I simply bolted on twin 1850's, and jetted them for the 464c.i. BBC and they performed fantastic throughout all types of driving from mild street use to drag strip use.

 

And the above boat use is far more forgiving than using them on the street in a car. So if they gave issues on a boat, they're magnified on a street driven vehicle!

 

I bought a Weiand with the say why and on it also. Believe it's from 1966 and it came with Carter 500 competition carbs. Was going to rebuild these for my 283 but now this threads got me thinking.

 

If those late model Carters are in good shape, or you rebuild them, they should work great. I had the same intake and used 600 Holleys on it bone stock without any changes and they worked great.

 

I was wondering about running 600 Holleys but thought they might not run right but good to hear that they can be used without a problem. Because of Covid lock down I'm still waiting to get my block into the machine shop to plain the heads and block.

 

The 1850 600cfm Holleys work extremely well on SB or BB engines since they have vacuum secondaries. The stock jetting is too lean for a BB motor in most cases, as they are #64 jets, but that's just about perfect for most SB engines. For a healthy BB like I had in my Falcon gasser with 464 c.i. engine I rejetted them to #78 jets.

 

I myself had no problems with the 450 mechanical secondaries on a tunnel ram, they needed properly tuned as any carb does but really ran great.
This was a city street driver with many many stop lights to contend with, drive 45 minutes to work in both city and rural roads, but also ran on the track every other weekend, I would leave at 2200 rpm off of a foot brake and it would pull the wheels every pass.



I liked them enough to pick up another pair for my crossram, I did put the rear plates in to except jet changes on these and I have another pair of 50cc pumps on stand by, this will be my 3rd pair of 450's



I do have a pair of 1850 600's in stock as well as a pair of Carter competition series 500's, this will be my first crossram so I'm covering all my bases lol

 

Does anyone have a bbc crossram for sale? The one i had a line on fell through.

 

I had been thinking of putting a cross ram on the 355” SBC in my Austin gasser. I mentioned it to a friend of mine and he said that he knew of one for sale. So today I scored a polished M/T cross ram in great shape. Unfortunately they polished off the M/Ts but it’s pretty obvious what it is. And best of all no corrosion and no “porting” was done on it. I have two 500 and two 625 AFB competition series carbs to try on it. The current cam is an old Comp Cams 292 Magnum.
Can anyone post some pictures of the linkage commonly used with this offset setup?

 

Nice manifold. Looks like it has rear water ports for cooling lines. As for linkage... swap meets, and a note in wanted section. Bet this manifold had chromed linkage ... still hanging on someones wall.

 

This is a edelbrock intake. It has bosses that are tapped for the linkage. Right upoer cornef.

 

I remember that linkage but with out the bosses on the M/T manifold I’m thinking that I’ll probably have to make something that bolts to the rear studs of the rear carburetor.
Here’s the cross ram I had on my first Austin. Sorry for the crappy old photos. Everything you see and more came with the car for $350. A 292 Chevy, a new C&O 4 spd Hydro, narrowed Chevy rear end w/4.11 posi, and new M&H slicks. An unfinished roller. The cross ram setup never gave me any problems but the hydro wanted to stop the little Chevy on the 2-3 shift. Fun car.

 

This is what I came up with, just need a longer rod for the right carb, some of the vintage photos I've seen of M/T had the linkage mounted to the front of the carbs.

 

What distributor are you guys running?? I have one for my BBC, pertronix with vacuum adv is too big and I really don’t want to run a $600+magneto type as I plan on driving on the street.
Thanks all

 

JMO I would run a pair of 660 center squirters on a cross ram just like I would on a tunnel ram. No power valve crap. Tune it with the jets. Big plenum requires a lot of fuel to fill it on demand. I feel most are trying to run these setups on the street and theres the catch. You may get it to run SATISFACTORLY on the street with 450's, 600's or 750 holleys. But it will never perform like it was intended because it was not designed for the street. But you can make it JUST hit on 8 and look cool, if that's your thing. Lippy

 

I'm running a factory points distributor but it's got an Accel electronic kit in it. It's working very good and no problems at all.

 

That's what I ran on my 377 in my Malibu, back in the day.

Once I got the proper cam in it, it was great.

 

cool thread

 

Pretty bold (in red), and baseless, if I may be so bold, comment, to include ALL...cross ram manifolds in this comment !
There are MANY different designed cross rams out there to be used. Large plenums, some with HUGE plenums, some with smaller plenums. Some will work better, some maybe not so much, but to say ALL...!
NOT true. I had an Offenhauser (like the Chevrolet Z-28) on a 350 in my car for many years, that ran very well. The reason that I know that it ran well, is that over the years, one thing that I did for the fun of it was to swap intake manifolds around a bit. Single plane, dual plane, and yeah, my Offy cross ram. My Man-a-Fre was on the car the longest, early on.

Carburetor size and the proper setup is important.

Mike

 

I run the Edelbrock X-C96 with (2) Holley 450 carbs. Engine is a square port head vintage 396/375 HP
Runs pretty good but I think 50 cc accelerator pumps would be a good idea.

 

Nice engine, and like Interior, I need in my Wagon..

 

Thought I would follow up as I installed the 50cc accelerator pumps. Noticeable improvement. Slight but bearable hesitation around 1800 rpm but nothing to really complain about.

 

It was a long time ago when I had mine (1977-78) but it worked very well for me. 14:1 427 with a pretty good set of heads, a 324/590 Sig Erson (one evil sounding sucker) and a pair of 4777's with primaries up a couple sizes and 3.5 PV's, and carefully set up to be as close to perfectly the same as I could get them, idle screws, secondary plate opening, linkages matched etc. One thing on my setup was that it was extremely sensitive to timing- just a couple degrees short and it would blow back severely out of the carbs and just be lame, but bump the timing a bit and it came to life- with the iron heads and 14:1 it liked 40 degrees. It was extremely responsive- it would devastate 13" wide tires from a 3rd gear roll at 35 (4.86 gears) and made believers out of several bigmouthed Chebbrainwashed who went for a ride

 

WOW, What a great thread. I'm in the process of setting up a X-C8 on a 383 SBC. Going with a matched set of Holley Quick Fuel 450's vac secondaries.
I've seen mention of a crossover tube to equalize vacuum, what about a pair of carb spacers connected together with a 1" tube? Do you think that would do it? Or 2 1" tubes, the number of tubes can be increased if it helps.

 

I can’t see why it would not work using the carb spacers.

 

So far, it runs great. Didn't touch anything on the carbs except the idle screws. They were perfect right out of the box.

 

Did you do the crossover tubes ?