Crossram and headers

[WaltZ]

anyone running a crossram with headers on the street cruising with 302 and 30/30 cam.
jettting:
font carb p65s and s68s
rear carb p71s and s75s
any thoughts on this.
thanks in advance,
Walt

[BULLITT65]

The 30/30 cam is not ideal for the cross ram set up, street or otherwise. I would recommend contacting Wayne Guinn through his FB group : https://www.facebook.com/groups/336597481642759
😉

[68camaroz28]

anyone running a crossram with headers on the street cruising with 302 and 30/30 cam.
jettting:
font carb p65s and s68s
rear carb p71s and s75s
any thoughts on this.
thanks in advance,
Walt

Hi Walt, we have a 69Z with Quinn certified cross-ram and carbs with repro headers BUT we have the original block stroked to 383 cu.in. and running a solid lifter roller. As previously stated normally not a good set up for the street and many things have to be done to make the set up street friendly.

[David K]

Making that thing “street friendly “ is a task unto itself. Looks cool, sounds great, a monster in disguise.

[crossboss]

Cross-Rams in general are not for the faint of heart. They are not a bolt on and go set up. Regardless of the brand, a Cross-Ram has a design with a large plenum, with long runners. Terrible for off idle (lean stumble), vacuum issues, terrible low velocity and usually the power bands are from 3,000 RPMs and up. Stroking or a larger cid engine helps. In my opinion, the best bar none Cross-Rams were the Chrysler Hemi 'Rat-Roasters' That said, Chevy and Ford made their versions for specific engines/applications. Each of those have good and bad designs. I can give you advise on what I ran (Cross-Boss, and Inline carb on a Ford 302), however that won't help here. Getting back to the subject on hand, my best suggestion is to talk to guys who run them and get your tuning advice from them on what works and what does not work.

[BRG Z28]

I currently have a 1968 Z28 with a all original crossram set up. The original carburetor were redone for street use. The car is extremely drivable and street friendly. If you went for a ride in the car you would not know it had a crossram under the hood, until I put my foot into it!
The key to making a crossram set up work; revamping the carburetors, headers and a transistor ignition.

Feel free to contact me if you would like some more in-depth information.

[David K]

I’d like to see some pictures of that!

[BRG Z28]

Original GM crossram, cowl plenum, headers, transistor ignition and J56 4 wheel disk brake.

[BRG Z28]

14,500 original miles, all original paint, factory stripe delete.

[BRG Z28]

Original blip top crossram intake with 4210 carbs. The only thing on the car that is reproduction is the positive battery cable. I am looking for a original one 😁
Again, the car starts right up, idles around 1200 rpm and drives like a new car.

[crossboss]

NICE!!!

[169INDY]

BRGZ

Great Post, Thanks for Posting. Boy I would like to see that Car!

Plug Shields W/ Kustom Headers, I will have to see if mine Fit  (ALL repops)

[Coltdogg556]

I started reading this post and I was going to say talk to Paul. I know he done it on 2 different 68 Z.  But as I was reading I see he done posted his beautiful car. It's a freaking tank. I know I am  going to set mine up as close as I can like Paul's 68Z.  Then only difference is mine will be getting a full restore job (way to far gone to even think about a survivor) then I will be doing a few re-pop parts like the headers,  linkage and some other hard to find parts. Then I will NOT be running the cowl plenum air cleaner.

As Paul said, the carbs need to be worked over for the streets. I would call Jarrod Wilkom with Allstate Carburetor.  I would also talk with Wayne Guinn with Guinn Engineering about the cam.

It also depends on what Holleys you are running.  You got the 4210's they are not the best to run, but then can be worked over good for street use.  Then you got the 3 digit date code 4295, the 4295 service carbs, and the 4295 re issued carbs. I read that the re issued are the best to run but getting harder to find.

Tom Cudeyro is also a well knowledgeable person when it comes to this as well.

Wish you the best if luck. Please keep us updated on what happens with it.

[69Z28-RS]

Replacing original Z28 intake/carb with a crossram generally means you want your Z28 (to look at).. rather than to drive...  but DRIVING a 'stockish' Z28 is so much fun! 

[cook_dw]

https://www.yenko.net/forum/showthread.php?t=169336&highlight=stripe+delete

[Coltdogg556]

Replacing original Z28 intake/carb with a crossram generally means you want your Z28 (to look at).. rather than to drive...  but DRIVING a 'stockish' Z28 is so much fun!

Not all true. I am restoring my car to drive. I may take it to a few small car shows here around the Oklahoma area, but but I am not doing it for a car show only car. The one listed above  and the one you posted are the same cars. I know Paul's car is a show winner but I do know he drives it.   Now I am not going to lie, you are right. Driving a stock 68Z is fun. I have not got to do that in many years but it was a fun car I was in.   

Now the reason I want a crossram is cause of my father. He is a big 56 Chevy guy and he done a few with a 2X4 set up and he loves it.  He is the one that helped me get my 68Z  and I thought the best way to honor him would be with the crossram.  Maybe I am crazy for restoring a driver with some of the baddest parts that was made by Chevy in the late 60's,  but its my dream car and I will not let anyone stand in my way.

[68camaroz28]

Replacing original Z28 intake/carb with a crossram generally means you want your Z28 (to look at).. rather than to drive...  but DRIVING a 'stockish' Z28 is so much fun!

Not all true. I am restoring my car to drive. I may take it to a few small car shows here around the Oklahoma area, but but I am not doing it for a car show only car. The one listed above  and the one you posted are the same cars. I know Paul's car is a show winner but I do know he drives it.   Now I am not going to lie, you are right. Driving a stock 68Z is fun. I have not got to do that in many years but it was a fun car I was in.   

Now the reason I want a crossram is cause of my father. He is a big 56 Chevy guy and he done a few with a 2X4 set up and he loves it.  He is the one that helped me get my 68Z  and I thought the best way to honor him would be with the crossram.  Maybe I am crazy for restoring a driver with some of the baddest parts that was made by Chevy in the late 60's,  but its my dream car and I will not let anyone stand in my way.

I applaud your enthusiasm and if you have ever checked my 68Z build thread than you know I also appreciate what you want to accomplish. Congrats and enjoy the journey..... Now, just a few words on the cross-ram as yes they can work fine but better find out in advance what has to be done. One of the main things is idle circuitry and using a recipe to assist with making it work fine. As stated prior we have an original Quinn certified cross-ram and carbs on our 69Z but its stroked, solid roller, and engine re-built from ground up to use the cross-ram (our recipe).  How's ours run, GREAT and not afraid to drive it anywhere. Congrats again!

[BRG Z28]

Thank you for the kind words. I drive my crossram Z all of the time without any issues. If it is set up right, the only issues you will have is keeping your foot out of it and stopping at every other gas station.

Normal driving around town, you would not be able to tell my crossram Z set up from a single four Z

- If I had to pick out some negative aspects of having a crossram;
- Starting it when it is cold out (no chokes)
- You have to keep a higher idle (around 1200-1500).
- When you put your foot into it, my car experiences a slight bog before it takes off. (This is especially seen with the 4210’s).

[BULLITT65]

Good point on the 4210. The stepping improvement of the linkage on the 4295 helped this out a great deal.

[crossboss]

Thank you for the kind words. I drive my crossram Z all of the time without any issues. If it is set up right, the only issues you will have is keeping your foot out of it and stopping at every other gas station.

Normal driving around town, you would not be able to tell my crossram Z set up from a single four Z

- If I had to pick out some negative aspects of having a crossram;
- Starting it when it is cold out (no chokes)
- You have to keep a higher idle (around 1200-1500).
- When you put your foot into it, my car experiences a slight bog before it takes off. (This is especially seen with the 4210’s).

These are common issues running a Cross-Ram.
"Starting it when it is cold out (no chokes)" No chokes and no heat risers. All that cold gas/air has not expanded yet.
"You have to keep a higher idle (around 1200-1500)." With that huge plenum and long runners there is no velocity. A higher idle helps build up the speed.
"When you put your foot into it, my car experiences a slight bog before it takes off. (This is especially seen with the 4210’s)." Not uncommon. Lean hesitation off idle. Needs more pump shot from the carb(s). Remember, any carb with a 1.1 opening rate will encounter horrible booster signals. MAYBE another carb(s) can and will cure these issue(s). Let the experts chime in on this one.
I experienced the same with my brand X set up. The fixes/cures are in the tuning aspects, time, and patience. In some cases, internal surgery was required on the plenum/runners/dividers.

[David K]

For those reading this thread who have never driven nor ridden in one, remember everyone has an opinion about this setup. I have ridden in one in one with chambered exhaust. They’re a beast to get warmed up and require some finesse to get moving from a stop… until they get some heat in them. If I ever get another project to build, I’m going this way because it tuned me in to what I liked.
I’m confident the engineers at GM didn’t casually put their stamp of approval on this and kick it out of the office. Do it right the first time using the correct parts, and all will be right in your crossram world. Pretty sure you’ll be the only one a the show or cruise or cars and coffee with one.
BUILD ON I SAY!!

[BULLITT65]

David you are spot on. It takes the right specific parts (T.I., headers, cam, etc) it also takes the right build. Wayne is extremely helpful , and very generous with his time throughout the process. He loves helping guys out to make sure they get it right. The cross ram is Z/28 history and really takes the car into the rare air territory. With the right build there is a lot of fun to be had, and it is second to none for how cool it looks.

[BRG Z28]

The bog off the line in my car is so slight, but I thought I would mention it. I was told playing a little more with the rear carburetor will minimize it even more. This is less of a issue with the 4295 carburetors, because they are double pumpers and have the “W” slotted progressive lineage.

The real key to drivability is headers and transistor ignition.

[David K]

As a follow up I will say the fun factor is worth every penny. The sound, the unruliness, the “not ready to drive yet and I’ll let you know it” is part of the charm. Serious personality disorder, but once you understand it…..
Next to the 68 Road Runner 426 Hemi 4 speed I was a 16 year old passenger in….
Or the GNX I was a passenger in-delivery driver had to move them around the trailer……FUN FUN FUN!!!
I consider myself lucky to have had the opportunities.
Forgot the ride in this one back in the 90s at John Hoopers US Muscle parts business. They had a Camaro show. See picture of car

[crossboss]

My worthless two cents...
My own experience with Cross-Rams (brand X), tells me the OEM Chevy 'correct' carbs for this application is not good for a street/mild performance for 'drivability'. Why? A 1 to 1 (X8!) linkage is horrible on the booster singles, and that alone will cause most of the issues in my view. The 'correct' carbs maybe the way to go for a show/race car, however, not the 'best' for performance. Try using dual 465-600 cfm vacuum secondaries or double pumpers carbs. This does seem to work well on the Brand X versions. Its not the name on the valve covers to worry about. Remember, Cross-Ram working 'theories' are very similar across all types...using a big plenum, long runners.

[BULLITT65]

Crossboss maybe for Ford, not the case for Chevrolet.
 I have actually interacted with number of guys running cross rams on the street, and 99% of them run a version of the 4295, wether original or re-issue, and get the most out of the set up that way. I do know one guy that ran a set of 600 carbs, and while he improved the performance over the stock 4 and tried many cams, and tweaks, it is still the original set up of the intake and carbs that seem to pull the best and the parts perform the best together. Martins recent engine build which went the route of find the best of the best to perform, also used 4295's, and they got 480hp on the dyno.

[crossboss]

Crossboss maybe for Ford, not the case for Chevrolet.
 I have actually interacted with number of guys running cross rams on the street, and 99% of them run a version of the 4295, wether original or re-issue, and get the most out of the set up that way. I do know one guy that ran a set of 600 carbs, and while he improved the performance over the stock 4 and tried many cams, and tweaks, it is still the original set up of the intake and carbs that seem to pull the best and the parts perform the best together. Martins recent engine build which went the route of find the best of the best to perform, also used 4295's, and they got 480hp on the dyno.

Not doubting your wisdom. Remember, the key on the street and mild track use is to gain drivability, throttle response and torque. Yes, any torque gained on a low torque engine like the DZ 302 is in my book better than 'peak' horsepower on a dyno. A dyno never won a race. Believe me I have raced, and street driven a car with a Cross-Ram. Yes, it was with a Boss 302. An engine that is the worst for low end response especially with a Cross-Boss, Inline carb, a radical cam that idled @ 2,500 rpms. A total dog below 4,500. On the race track, look out. On the street, it was a fine line on being un-street worthy. Yes, different animal, different engine. Same type of intake manifold. Just passing along my perspective on all of this.

[MO]

I have a friend with a stock 302 and ignition, crossram, headers and chambered exhaust. I have driven it many times and it is the easiest of high performance cars to drive. No hesitation or stumble and no excessive high idle. It can be done, you just have to figure it out.

[BULLITT65]

There are tame Cross ram builds as well. Wayne helped Gene with a build last year and the goal was performance but with street drivability. In the end it was not a radical built motor but one that had a great amount of giddy up, but idled well and the power band came on way smoother than the a track based brute with gobs of power that only comes in at a high rpm. The are many different way to skin a cat. 😉
So to your point Crossboss, there is some sacrifice with having street/strip machine with it, but there are plenty of guys who have mastered how to do it. The 480HP number is impressive because it was a build meant for the street and to have street manners but still be able to utilize that kind of power consistently less the trifles under lower rpms.

[crossboss]

There are tame Cross ram builds as well. Wayne helped Gene with a build last year and the goal was performance but with street drivability. In the end it was not a radical built motor but one that had a great amount of giddy up, but idled well and the power band came on way smoother than the a track based brute with gobs of power that only comes in at a high rpm. The are many different way to skin a cat. 😉
So to your point Crossboss, there is some sacrifice with having street/strip machine with it, but there are plenty of guys who have mastered how to do it. The 480HP number is impressive because it was a build meant for the street and to have street manners but still be able to utilize that kind of power consistently less the trifles under lower rpms.

I agree with you. The Chevy would be a better 'drivable' version with a Cross-Ram then say one with a Boss 302. Big port engines on the street are very lazy. Maybe that is the key here. Hopefully, one day I will own a '69 Z/28 with a Cross-Ram!

[BRG Z28]

I feel there is nothing sweeter then opening a stock hood and seeing two Holley sitting on top of a little 302!

[BRG Z28]

My best results with the 1969 4295 carburetors were;

- 64 jets primary (stock is 69)
- 71 jets secondary (stock is 71)
- 2.5 power valve (stock is 6.5)
- .37 squirters (. Stock .25)

I also changed to a “green” carburetor cam

I have 4210 carburetors now and made similar changes, but unfortunately I did not write them down. 

[crossboss]

I feel there is nothing sweeter then opening a stock hood and seeing two Holley sitting on top of a little 302!

Amen, brother! A nice Z with the Cross-Ram dual Holley's and its rival Boss 302 with the dual Dominators is just pure car porn!

[David K]

I wonder I’d I can fabricate this setup to fit my inline six cylinder? Now that would be sweet!

[169INDY]

^^Clifford's Dual Fours for a six ^^
LOL

[David K]

No sir! Only Genuine GM parts. That would be a sight!