1957 C1 Front cross member

[Dan P.]

Does any one know if there is a difference in a 1949-1957 Passenger car font cross member and a 1957 Corvette .

[Mike M.]

Re: 1957 C1 Front cross meber

yes, there are differences (extra holes and lack of holes). i bought a nos 49-54 pass car front x-member for my 57 fi vet . the original was the rustiest pos i'd ever seen. i simply used the original as a template to weld and grind unneeded holes in the nos piece. and drilled hole where the nos piece lacked holes. took an hour or so to accomplish. regards, mike

[Cecil L.]

Re: 1957 C1 Front cross meber

Tom Parsons can tell you everything you need to know about the 49-54 pass vs 53-62 Corvette front suspension complete with pics.

[Tom P.]

Re: 1957 C1 Front cross meber

Dan,
The BARE, BASIC 49-54 pass car and the 53-62 Vette front corss members are exactly the same. As Mike already pointed out above, there are some MINOR differences in holes/lack of holes between the car and Vette cross members. The additional holes in a pass car cross member will be completely covered up by the Vette fan shroud, thus, that's a non issue (of course, you can weld/grind them if you prefer).
Additional holes (4) need to be drilled in a pass car cross member. Two for the front brake line clips and two for the forward two bolts in the center steering arm bracket.
All other front suspension parts are a direct bolt-on interchange. Toooooooooooooo easy!

[Michael S.]

Re: 1957 C1 Front cross meber

I believe the spindle supports have different casting numbers also.

[Tom P.]

Re: 1957 C1 Front cross meber

I believe the spindle supports have different casting numbers also.

That is correct. But, ALLLLLLLLLLLLLL 49-54 pass car and 53-62 Vette spindle supports are PHYSICALLY interchangeable. The SIGNIFICANT difference is the 53-54 pass car spindle supports. The knuckle for the kingpin is positioned about 1in higher on 53-54 pass car supports (which lowers the frontend). Even though the 49-52 pass car and 53-62 Vette supports have different casting numbers, they are physically the same and interchangeable.

Here is a comparrison between 53-54 pass car (left) and 49-52 pass car/53-62 Vette (right) spindle supports.


"Back in the day", some racers used to swap 53-54 pass car supports onto their early Vettes to drop the frontend slightly. Doing this, along with the 57-59 HD springs will noticeably drop the frontend (which of course lowers CG). This is definitely good for road racing handling, but not so great for regular street driving. I certainly don't want my 56 dropped any lower than the stock height.

[Michael S.]

Re: 1957 C1 Front cross meber

So as to not confuse the OP. The '49-'52 passenger car front end is a direct replacement with the exception of a few holes. But the '53-'54 passenger car spindle supports will not result in the correct front end height for a Corvette.

[Tom P.]

Re: 1957 C1 Front cross meber

Well, yes.
The ORIGINAL question was only directed at the bare cross member itself-----------------without any other parts/suspension components (that is, as I understood it).
If a 53-62 Vette BARE cross member and a 49-54 pass car BARE cross member (BARE is the key word here) are placed side by side, it can be easily seen that they are the same, and are a 100% direct bolt-on interchange.




Now, with that said, there are some differences in holes between each cross member, depending on pass car or Vette application.
There are also some differences in some of the steering components--------------BUT THEY ARE STILL BOLT-ON SWAPS!!!!

The pass car cross member has an additional hole on top (WHICH WILL BE COMPLETELY COVERED BY THE VETTE FAN SHROUD) for the center steering bracket. BOTH the Vette and pass car cross member share the same REAR holes for the center steering bracket, BUT, the pass car cross member does not have the two front holes. These two front holes can be added to a pass car cross member simply by using the Vette steering bracket to locate the holes.
The pass car does not have the two holes for the front brake crossover line. Too easy to locate and drill them.
The 49-51 pass car cross member has two holes on top (again, completely covered by the Vette fan shroud) for engine mounts. The 52-54 pass cars switched to side engine mounts, thus no holes in the 52-54 pass car cross member for engine mounts. The extra holes in the pass car cross members (if a person chooses) can be welded and ground smooth.
The brackets/holes for mounting either cross member to the frame rails are the same.

Steering.
Pass cars and Vettes have different center, L&R steering arms and different tierods. The pass cars have an adjustable tierod ONLY on one side. The tierod on the other side is a ONE PIECE solid rod and ends.
The L&R steering arms are at different angles for Vette and pass cars.
The center steering arm on pass cars is hinged with a kingpin/bushing type setup. The Vettes used a HD ball bearing and both the mounting brackets and center steering arms are totally different. I don't have a picture of the pass car center arm/bracket, but below is the Vette setup.




All of the replacement parts for both pass car and Vette frontends is the same---------------------EXCEPT the Vette uses two L&R tierod ends and the pass cars only use one L&R.

Spindles, upper and lower A-frames, brake backing plates (51-54 pass cars), brake hardware are the same as well as all the misc small parts. The ONLY things that become different/unique for the Vette frontends is the HD brake parts. Also, because the Vettes are lighter, they have different coil springs (DO NOT put pass car springs in a Vette frontend!!!).

Now, since this has become so lengthy, I'll add just one more item.
The LOWER A-frames are left and right, BUUUUUUUT, they are exactly the same. What makes the difference between a L&R lower A-frame is the bracket that is spot welded on the bottom for the sway bar (stabalizer if you must be exact) link. If a lower A-frame needs to be replaced (whether it's L or R), and the correct side is not available, then the 4 spot welds can be carefully drilled out, swap the bracket to the other side and a small spot weld can be placed in each hole. Now a lower A-frame has been made for the needed side. Toooooooooooooo easy!

[Terry D.]

Re: 1957 C1 Front cross meber

Tom, Sounds like a great article for the Restorer! That way everyone would have a copy, I know I would like a copy.

[Vinnie P.]

Re: 1957 C1 Front cross meber

Tom, Sounds like a great article for the Restorer! That way everyone would have a copy, I know I would like a copy.

I agree completely and would welcome the opportunity to publish an article by Tom so all 15,500+ members can benefit, not just the 275-300 that sign on here each day.

[John D.]

Re: 1957 C1 Front cross meber

Tom, Didn't know you were so educated on those suspensions. Good job. John

[Michael S.]

Re: 1957 C1 Front cross meber

I agree. It would make a fantastic article for the Restorer. Tom did a great job. I would enjoy reading it. These types of discussions are what I believe makes this a great organization.

[Bert L.]

Re: 1957 C1 Front cross meber

Bravo Tom!..... that is terrific information and I to hope you'll submit an article for publishing in The Restorer. *Cheers*

[Jerry W.]

Re: 1957 C1 Front cross meber

Where have those of you just now recognizing Tom's wealth of knowledge been.

Would like to see any future article on Tom, expanded to include his 55 Vette....( Car is not NCRS, but alive and well )

Here's a couple of other valuable Tom rebuild links.


.
http://www.chevytalk.org/fusionbb/sh...hp?tid/218134/



http://www.chevytalk.org/fusionbb/sh...?post/1788397/