rocket rear end measurements/ birdcage placement

[andy16]

what are measurements from the bell machined surface to center of shock mount left and right. assembling a rear end that is not under the car at the moment. thanks

[billetbirdcage]

For someone to answer, they are gonna need what year and what type car: black, blue/grey, xr1?

[Jking24]

If you call rocket they will gladly give you any information you Need

[andy16]

For someone to answer, they are gonna need what year and what type car: black, blue/grey, xr1?

Right, sorry about that. 2004 black front end car. its actually a black front end rear clip on a chevelle front clip as a modified. i have ruhlman/keyser birdcages and its a 60'' centered gn quickchange. ump legal car im building myself. i could call rocket or ruhlman but im trying to respect thier work load for paying customers as i have not bought my car from either of them. in time i could figure it out with putting it under the car and trial and error but im hoping someone can throw me a bone. id like to have the rear end assembled outside of the car correctly so i can get the steel tubes painted and everything just right before i put it under the car. i believe the only way to set the cages correctly is to have the measurement from the bell to the shock mount, because its now a 60'' steel tube gn rear under it im not sure how that compares to a wide 5 tube/rotor/hub placement. also will winters steel tubes rust? are they stainless?

[TheJet-09]

If you are admittedly using a different width rearend, but leave the upper shock mounts in their original locations, setting the birdcages to the OEM specs laterally will undoubtedly cause the rear shock (I guess in the Modified world, just the spring) angles to be off. I think you'll have to ultimately come to some sort of compromise to get it to work, and I would envision having to do that with the rearend under the car.

[andy16]

No , if the cages and shock mounts on the rear and on the chassis are set to rocket spec all angles will be exactly right wich is what I’m trying to do. Ruhlman brucebilt tomahawk throwing dirt cars all have used stock rocket rear clips with 60” rear or 62” rears. I just need someone to run a tape measure from the bell to the shock mount on the cage and I can take take it from there please.

[TheJet-09]

I've never spoken to any of the builders you mention, but I'm sure the info you need is something they know off the top of their head. I understand your wanting to respect their "workload for paying customers" but it would also give them the opportunity to possible earn your business by helping you.

That or maybe ask in the Modified section? Either way, good luck.

[andy16]

the answer is 12 l/s and 16 r/s i believe

[05modWrench]

Ruhlman uses a 60" rear with 2" offset. The measurement from the machine surface on the bell ( where lift arm brackets mount) to center of 4 bar is 18 3/4" left, 21 7/8" right. I'm not positive what that means for you though.

[andy16]

I talked to him on Friday he told me those measurements were 17 and 21 and 3/4 , not sure what’s going on here but when I get it sitting under the car I will follow up . Your measurements look more right to me , 17 on the left looked awful short but I promise you that’s what he told me on Friday. At this point the best thing is for me to get it under there and see . I appreciate everyone’s replys


Ruhlman uses a 60" rear with 2" offset. The measurement from the machine surface on the bell ( where lift arm brackets mount) to center of 4 bar is 18 3/4" left, 21 7/8" right. I'm not positive what that means for you though.

[let-r-eat]

I don't believe the Ruhlman 4 bar bracket placement is the same on his rocket rear clips as the LM.

[andy16]

He told me on Friday that it was , that I could measure a latemodel and it would be the exact same . I don’t know it should be this hard to get some back front end rocket measurements anymore it’s 20 year old technology. I called rocket on Friday also all Robbie could tell me was what the new cars are and mine is not the same. I asked a few people near me could they go measure there’s for me they said no . So it is what it is. I will get it right the hard way I guess.

[CCHIEF]

I believe if you call Frankland,I highly believe you can get the exact specs for any Rocket car and any cage used by Rocket. No longer have a black FE car or I would gladly pull a tape for you and snap a picture of Radius Rod placement (inside outside of cage). Here you go: 1-888-8-REAR-END https://www.franklandracing.com/contact-us/ I believe if you search these tech forums you will find the info, as I recall this has been asked more than a few times over the years.