I am fixing to cut out the old backhalf of my tubbed 67 camaro and redo it alot better and nicer,my ? is the wheel base.I measured the camaro wheelbase and it is 107 on the passenger side and 108.5 on the driver side,this is how it was put in by whomever tubbed it the first go around im assuming.I measured my 68 bird and it is 108 1/4 on both sides.What is the correct wheel base for these cars and should I just adjust my marks to be the same before I cut out the old and put the new back in,I have never done one of these before but I have researched it all and a buddy of mine and his dad did one and it doesnt seem like it will be very hard I just need to figure this measurement out or how to fix it then cut it all out so I'm hoping some of you guys with prostreet cars can answer my ?s through this process.There is a noticable difference is the way the tires sit in the wheel wells but this car has also had 80% quarters put on at one time which will be changed after the new back half is installed.Thanks for any info you can give.

108" is what the wheelbase "should be". Now before you cut out the old stuff make sure it's just not adjusted incorrectly. 4 links and ladder bars can be adjusted and maybe the car wouldn't leave straigh so they compensated.

In either case it is a lot of work to back half a car but, since your car is already cut up that will make it easier.

The first thing you need to figure out is if the rear end is off or is it the front. Don't assume anything. If you can find a reference point on the frame to measure from that would be a good place to "verify" what is off.

Once you verify what you have, use a plumb bob and get your front axle center line. Mark the floor on both sides, then measure 108" and mark the floor for your real axle center line. You can then hang a plumb bob from the rear quaters down to your mark on the floor and see if the wheel opening is right or not.

You can also measure in an X to see if your front wheel center line is straight.

Does that help?

my car does not have any of the old floor or rear frame left in it from the previous backhalf,I measured with a square on the floor from front left wheel center to B pillar and got 79 3/4in and left rear center to B pillar and got 28 3/4in

I repeated these steps on the passenger side from front wheel center to B pillar and got 78 1/2in and from rear wheel center to B pillar and got 28 1/2in

I dont know if this a good spot to measure to I just couldnt think of anything else since all the original rear stuff is gone.Its a full 1 1/4 in difference from side to side and that doesnt seem right to me but I dont know,If there is something else I can measure let me know and I will do it.This car does have ladder bars on it now and I'm sure I could make the total wheelbase right but the front to B pillar is bothering me alittle bit,Thanks

Chris,

This is how I did my car and the pro touring car I doing right now. It might be back yards but this is all I had.

Are the quarter panels put on in the right spot. They should match the bottom front lip of the rocker panel. You want your rear tires in the center of the opening and the measurements from front to back so the car tracks straight going down the road.

The first thing I would do is make sure the front subframe is in correctly. There is alot of discussion on lining up the subframe from the AIM manual. Do a search in the body shop section on how to align it. Align it first so you will have a good reference point.

With the car level on jack stands I would set it up with some plum bobs. Us a 4 ft level across the bottom or top of the rocker panel. Also try across the trunk to level it side ways. I would remove the front tires and turn the spindle and put a level on the top 2 wheel studs and hang a string off the bottom wheel stud. Do this on both sides. Put masking tape on the floor to do your marks while you are doing your measurements.

Have the rear end on a jack at ride height just to hold it up. Do the same thing on the back axles with the wheel studs / plum bob. Also put masking tape on the floor in the back. Mark it where the plum bob hits the floor. Measure front to back and in the ( X ) and see what you come up with. Is the rear axle in the middle of the quarter panel opening. You can adjust the ladder bars to do the adjustments.

Another thing to look at with the rear tires on the car, is the rear end centered in the car. You can run a plum bob on the lip of the quarter panel opening and then measure to each tire to see if the rearend is centered in the car. This will be hard to change since all the brackets are already welded in.

Try this and let use know what you come up with.

I have had several '67's & '68's. Wheelbase was anywhere from 108" to 108.75" +/-0.5" per side on the same car.

My present is 1/2 inch difference between sides and I corrected it by making/using an 1/2 inch offset button for the rear axle spring pad/bolt.

Everett is right, it's not unusual for any of these old cars to be off a little. It would actually be shocking if you found one that was perfect.

Since your car is backhalved and wasn't done very well, I would suggest you get your front axle center line straight (meaning wheel straight forward) and then mark the floor and measure back 108" on each side, that's where your rear axle center line should be. Build around that measurement and make sure the rear axle is square to the front wheels. I would not build around body panel measurements these older cars are not built perfect by any means.

You want to make your wheels / frame / rearend square. All I was saying about the body panels is you want to end up with the tires in the middle of the quarter panel opening. If your panels are way off like you mentioned then make the frame square and build the body panels from there.

thanks for all the info guys,I am fixing to get out in the garage and take some measurments and get it ready to cut out the old stuff,If I got anymore ? I will let you guys know and I'm sure you can help me cuase what you've told me allready is more than I started with,Thanks again

You want to make your wheels / frame / rearend square. All I was saying about the body panels is you want to end up with the tires in the middle of the quarter panel opening. If your panels are way off like you mentioned then make the frame square and build the body panels from there.


Mike,
I wasn't dis-agreeing with you. We are basically saying the same thing.

Guys'
Excellent information in this thread!!! :thumbsup::thumbsup:We need more of this type of information as it will most certainly help someone like myself who has limited knowledge and experience with certain aspects of hotrodding and fabrication.

If you draw a string from the bottom ball joint zerk and the steering arm/tie rod zerk from each front wheel, the rear intersection of the two strings is the center of the rear axle.

From there, a diagonal measurement from the lower ball joint to the same outboard spot, left & right, on the rear axle, will place the rear axle square with the front axle lateral centerline.

guys my car still has the original bushings under the front end but I didnt want to redo the frontend yet,I took some measurments from the holes that are used to allign the front subframe to the rear axle centerline in the X pattern and it is 1/2in difference.from pass front to driver rear is 107 3/4 and from the driver front to pass rear is 107 1/4 and this is the side that my wheel base only 107in and the tire doesnt look centered in the wheel well.is this a good measurment to go buy and what do you guys think.Thanks

Align front tires with side of the body, use a yardstick on the sidewalls to the door, both sides should be equidistant.

Measure from spindle center to rear axle center.

You measured the squareness of the front clip to body. Fenders align with doors, cowl good?

fenders and cowl seem to allign pretty well,I was trying to find something to check the rearend against to see it it is square in the car cause it is a backhalf ladder bar car now just awful work and I want to redo it.

Mike,
I wasn't dis-agreeing with you. We are basically saying the same thing.

Royce,
I know you were'nt disagreeing with me. We were talking the same thing but his wheels are not straight in the quarter panel opening. Its hard to explain this unless you are right there doing it. I saw your frame work and it is very nice. I did my car 17 years ago before they had any books on it. I just said what the hell and started cutting.

Chris,
I would buy a set of frame bushings and get the front frame straight first since you have nothing in the back to reference from. What kind of shape are the front bushings in? I would hate for you to go thru all the work of aligning the front subframe and have to redo it when you change the bushings.

Mike,I took some measurments like you said with all the tires off and leveled and plum bob'd everything.I came up with a 109 1/4 in wheel base on the driver side and a 108 5/8 on pass side.my cross measurment from front right to left rear is 124 and left front to right rear is 124 3/8.

I also measured the left front axle centerline to the front rocker edge and got 32"
I also measured the right front axle centerline to the front rocker edge and got 31 1/2"
I found that after I took the pass front wheel off the leading edge of the lower control arm is folded all the way under from taking a good hit on something in the past and dont no if this will acount for the 1/2" difference in these measurments or not.I did take some measurments from factory holes in the frame forward of the front axle centerline on both sides and there is only about a 1/16" difference.

I also measured from the left B pillar edge to rear axle centerline and got 29"
I also measured the right B pillar edge to rear axle centerline and got 29 1/4"
This is the measurment that the guys a Chris alstons chassis works told me to go by when my kit gets here to install the crossmember for my new 4 link and not to go by the wheelbase cause these cars can vary so much.

I also took some measurments on my rearend
it is 52" from mounting flange to mounting flang
the rear is offset 1" to the right side in the car
I have 11 1/4" from outer quarter panel to wheel mounting flange on driverside
I have 10 1/4" from outer quarter panel to wheel mounting flang on pass side

I was told when I ordered my kit that in these cars stock engine and tranny location are offset an inch to the pass side I believe and they said my kit would be built like that cause my stuff is in stock location still ? does this sound right and if so what should I do about my rear being to the pass side 1" I need to figure this out so I can take the right measurments and correct it if possible,Thanks

The rear end offset is normal but, I think it varies from car to car. I know none of them came centered. Since you are doing a complete back half it's up to you if you want it offset or not. I centered everything on my car but, I did a full frame.

Can you measure front the center of the rearend where the driveshaft hooks up to the axle flange. Do this on both sides. When the rearend was narrowed IF it was done right they would have offset it 1". Meaning from the center one side would measure 24" and the other side would be 25" so the center chunk was 1" to the passenger side. ( These arent exact measurements )Now center the rearend between the quarter panels and fit all the 4 link brackets on the rearend. If the rearend isnt built with the offset then you will have to leave it equal unless you want to build another rearend with the offset.

I would also replace the lower control arm and retake the measurements to see if they change.

When you looked at the car before you took it apart was the tires in the middle of the quarter panel opening or was the passenger tire 3/4" off? Or was both crooked in the opening. If you move one side it will also move the other side. Did the car track straight down the road. Your measurements are off 3/4" from both sides. When you put the new backhalf on the car all the measurements will be the same when you are done if you set it right.

Mike,the pass side tire looked closer to the front of the wheel opening than the driver side.I never drove the car,I went to alabama and bought it got it home looked it over real well and decided I didnt like it much and wanted to redo it.The guy I got it from said it was scaled out and ran straight but I did not want to find out as the work looks pretty bad and I am to picky to leave it like that.

I will measure the rearend today and see if it is right.If the rear is not built with the offset and I have to leave it equal what will this do to my drive shaft since the engine and tranny are offset an inch and they said my rear frame section will have a 1in offset built into it?Thanks

Chris,

I really dont know what will happen with the rearend being centered. Bad u-joint angle, vibration. What I would do is call a rearend or driveshaft company like Dennys Driveshaft and talk to them about it. I really dont think it will be a problem but I might be wrong.

I've read this whole post and just to chime in a little is the cross member square in the car,are the hime ends all adjusted the same.Are the quarters the same from the back of the door opening,are the quarters stretched...As for the drive shaft the don't center it because it wll vibrate from what I've heard...Its weard that I missed this post I guess I need to check in on Pro-Street more often.

Dave,the cross member looks pretty square in the car
all the rear heims on both ladder bars measure about the same and there is only about 3 threads difference on the front heims the left being longer
the quarters measure the same from the back of the door opening and from the left B pillar to the left rear axle centerline is 29" and this same measurment on the right side is 29 1/4"
The quarters are not stretched the are 80% quarters over part of the existing quarter which puts the out far enough that my rear bumper is touching the quarters on each side.

Mike,
I measured the rearend and it looks as if it has an inch built into it,the left side is longer than the right side but it is still offset in the car 1" measured from the wheel mounting flange to the quarter panel edge using a plumbob.Thanks guys

Chris,

When you redo your rear suspension you are going to cut all your old brackets off and then when you put the new brackets on, you will have it centered in the car. It is just a matter of redoing the rear suspension.

Ok Mike,I will center the rear in the car and position the new brackets on in the right location.Do you think I need to go by the wheelbase measurments on this car or use the measurments from the B pillars like they told me I will use,if I dont need anymore measurments than I am almost ready to cut out all the old stuff and clean it all up and get ready to install the new stuff when it gets here,Thanks for all the help.

I would use both as a reference. You already see the obvious problems with your car. Do alot of measuring and tack weld your backhalf before you fully weld it together. Make sure everything is level and double check your measuremants. Then stand back and look at it before you weld it. I hope you can look at something and tell if it is square and level. LOL

I've read this whole post and just to chime in a little is the cross member square in the car,are the hime ends all adjusted the same.Are the quarters the same from the back of the door opening,are the quarters stretched...As for the drive shaft the don't center it because it wll vibrate from what I've heard...Its weard that I missed this post I guess I need to check in on Pro-Street more often.

David,

You need to tighten up buddy, you were the one pushing the prostreet forum. Come hang out more often.

Chris,

Have you decided what you are going to do on your car. What kinda rear suspension are you going to install? Are you going to stretch the quarter panels or are they already done. Do you have any pictures of the car?

I am waiting on my new alston chassis works pre welded frame with exhaust holes in it and my new pro street 4 link with panhard bar to get here,should be here tuesday the 9th.I can not use a track locator as I made my frame alittle wider than most at 34" outside to outside and am pretty much going to do a large mini tub on it as I like a little smaller tire.I have strange adj. coilovers to go on it as well,I am not going to stretch the quarters but I do have to intsall new full quarters and tail panel and deck filler panel after I get the new frame installed.I do not have any pics at this time but I really need to take some.

Hey Mike,I got my new backhalf stuff in and am still trying to decide which measurments to go by.I went ahead and measured my wheel openings and from

left bottom front rear wheel opening to rear axle centerline is 16"
left bottom back rear wheel opening to axle centerline is 15 1/8 These total 31 1/8

right bottom front wheel opening to rear axle centerline is 15 3/4"
right bottom back rear wheel opening to axle centerline is 15 3/8 these total 31 3/16
only a 1/16 of an inch difference in the two wheel wells but 1/4" difference from the front wheel well opening on the driver side to the pass side and the pass side is the one that is visualy closer with the tires on.

The directions with my 4 link setup want me to place my cross member 26" forward of my axle centerline,with the way my wheel base measures now and the way the tires sit in the wheel wells I dont think there is any way to make the wheel base very close to 108 so tell me what you think,Thanks

Can you adjust your bars to center the wheels in the wheel well. I would measure from the front quarter panel to the center line of the axle.

How far off from 108" is it. They are not all the same, they will vary alittle. When I built my car I did not worry about the total wheel base measurement. I made my tires fit the middle of the wheel well at ride height. Now my car is a ladder bar car and when you lower the rearend the tires will hit the front of the quarterpanels so it has to be at ride height.

The four link bars are adjustable so you can align the rearend once the back half is in.

I would lay the frame out on the floor and level with the four link bars on and the rearend brackets. Do some measuring to see where the cross member is and then see where it measures where the rearend is now. Which is what you did already?

Just double check all the measurements first.

from front of the quarter panel to axle centerline on driverside is 29"
from front of quarter panel to axle centerline on pass side is 29 1/4" and this is the side that is closer to the front of the wheel well than the other side.
Any other part of the body up front I would be able to take a measurment from to the rear axle centerline to get a good measurment,Thanks

Chris,

Is the car level and is the rearend level when you measure it?

car is pretty level,where are you leveling the rear at.

Across the tube if there is enough area to put a 12" level on it. You might have to use a protractor.

Hey Mike,I had to get some more would to set the car on under the rocker panels and it is pretty level from front to rear,my rear is just hanging by the coilovers because if I try to jack it up at all right now it wants to lift the car off the wood blocks.,with it set this way I redid my rear axle centerline on each side like you descibed in an earlier post and then remeasured my B pillars to axle centerline and it is 29 1/4 on driverside and 29 3/8 on pass side,pretty close so I popped a chalk line.

I am trying to get the car centerline in the rear but I no my rear is offset in my quarter panels,it is 11 1/4 on the DS and 10 1/4 on the PS.should I move my mark 1/2" to the driver side to center it in the quarters.My new rear frame assembly has 1/2" offset built into it towards the pass side because of the engine tranny offset.

I also took a rear centerline measurement based on where the rear is located now and it is 1/4" difference from my quarter panels to the pass side of the car.

I measured from rocker to rocker and made a centerline mark but dont know if that is a good measurement or not what do you think.

I think I am going to go by my B pillar to axle measurments cause they are pretty close but just need to figure out my car rear centerline so tell me what you think is best,Thanks for all your help.

You are going to have to cut all the brackets off the rearend and center it in the car. That way your wheels will look right. You dont want to walk around and look at both sides and see one side off by a inch. You are more or less starting over. I would go off your B pillar measurements. Just make sure to only tack the rear frame end and then mock up the rear end suspension. Then start measuring everything again, front to back and by the ( X ) measurement. Once everything is where you want it then do the final welding.

Allright,I will be cutting the old cage and suspension out starting tommorow,I think I have enough measurments to go by.I sure do appreciate all the help you have given me in our continued conversations to help me get this right,Thanks Mike

Chris,

How is the car coming? Do you have any new pictures of the suspension??

Mike,its coming along slowly,had to buy my new welder before I could do much,got everything cut out and got the new frame cut and tacted in,have to cut all the old brackets off the rear this week or weekend and get it under the car and set in place.I am thinking of ordering the checkered racing front clip but not 100% sure yet and may have to do some front floor pan work cause of the previous owners hack job.Me and the wife just got back today from taking my oldest boy to six flags this weekend so I am going to try and work on the camaro some this week.I will try and get some pics and post them up if possible.