Chassis Questions

[62ImpalaSS]

I need some advice here, since I am new to all this car restoration stuff.

Here is my question:

1. I have noticed that some of you have installed frame braces at the rear like these from Global West. http://www.globalwest.net/1958-64_Impala_rear_frame_supports_TS-84.htm are these necessary?

2. Also I am considering a second Upper control arm at the rear is that a necessity as well?

3. Also is a posi rear end needed? I have a 3.77 non posi right now that is is good shape and I would like to reuse that.

The goal for the car in the end. I am building a 409 for the car, it will be a mild engine, 340 hp to 400 hp at the most. I am going to use Jim's truck build guide lines and I am on a budget so most likely the 340 hp build right now. The car is intended to be a cruiser for weekend trips some shows, Maybe a Thompson trip when finished. I am not building a car that is going to see track time.

Just looking for some advice so that I can move forward on getting the frame to the powder coaters and start putting this thing back together.

 

[4onthefloor]

IMO you don't need any of these. The Posi is nice but not really a necessity either.

 

[roger gunter]

I have to agree with 4 on the floor
nice to have but not necessary

build it to have some fun with

you can always add these items later on

jmo

roger

 

[63z11]

braces

Unless you plan to run it hard with slicks. You should'nt need those braces. The posi is really not necessary either. Get er going first then worry about Smoking both rear tires.bang

 

[boxerdog]

chassis

at the risk of being clear out in right (or left) field somewhere, my humble opinions:

1) The braces are nice and cheap insurance. That alleged crossmember is thin and weak and was even a problem in the 60s sometimes. Plenty of old X frames have a "repair hole" cut in the floorboard to expedite repairs. I'd add them and a GW arm and bracket if the budget permits.

2) The extra arm is period correct, fine for drags, not needed for anything else; might even bind up the chassis a bit in turns.

3) Wait until you need/want the posi, you will know when that is.

just my .02

 

[62ImpalaSS]

at the risk of being clear out in right (or left) field somewhere, my humble opinions:

I'd add them and a GW arm and bracket if the budget permits.

could you clarify for me what a GW arm is?

 

[jim_ss409]

could you clarify for me what a GW arm is?

Global West.

The transmission you've got makes quite a bit of difference. If you're running a 4 speed you should probably install the brace but you'd probably be fine without it if you've got an automatic.

Dave, "Petepedlar" built a nice 350hp 409 a while back that would be a good blueprint to follow. I looked for the thread but couldn't find it but I think it was fairly close to what we guessed at for the 350hp truck motor. He did dyno that engine so it would be a good thread to find.

 

[mark johnson]

I definitely plan on installing the extra upper control arm and the Global West braces on my '62. I had a high school buddy with an EXTREMELY good running '64 Impala that his father had purchased brand new with a 327-300 HP 4-Speed. Once my friend got the car, it ended up with 4.56's and some engine modifications and was capable of 12.70-80's. It had actually ripped the rear upper crossmember away from the framerails! After he fixed it somewhat, it ripped out again and he just harvested the good stuff from the car and sent it to the boneyard. I think adding the second upped arm on the Driver's side helps distribute that load somewhat and has been a well-known modification that's been done on these cars since they were new. There was even a factory revision in mid-'64 where GM themselves welded in some bracing to that upper crossmember on higher-HP cars. Maybe someone has pictures of these factory '64 braces. As far as the Global West braces, they bolt directly to the opposite side of the crossmember with the same 3 attachment bolts and then the front section of them needs welded to the frame rails. They look pretty nice and were about $90 bucks per side.

 

[4onthefloor]

Extra support

Mark here is the extra welded in support.

 

[62ImpalaSS]

Thanks Guys-

Jim- I figured out GW on my drive home, and did a . My mind must be slipping. I will look for that other thread I may have subscribed to it knowing I was going to do something similar.

I have the second control arm I will just need to order the second bracket and the GW braces. I have a T10 4 speed that was in the car when I got it so that will go back in there after getting rebuilt. So now there is some more mocking up to do before the powder coaters.

Jim was this the thread you were talking about? http://www.348-409.com/forum/showthread.php?t=16873

 

[jim_ss409]

Jim was this the thread you were talking about? http://www.348-409.com/forum/showthread.php?t=16873

Yeah, that's the one.
It sounds like a good combination to me. It makes good power at a relatively low rpm and should be a nice low maintenance engine. A setup like that should also idle quite smoothly and give you good fuel economy.
You could easily make more power by using a bigger cam but if you want good street manners you wouldn't want to go too much bigger. An extra five or ten degrees @.050 might be OK but it's pretty nice just like it is.
You might want to PM petepedler for more details.

 

[62ImpalaSS]

Some additional questions

Ok I have ordered the frame Braces from GW, and a bracket for the second control arm.

On the second control arm I have read about locating them and I will drill the holes when I have the GW braces just to make sure things line up.

Here is the question on the bracket on the axle housing. I am putting 2" lowering springs in the rear so when I am locating that bracket do I set the axle at the factory ride height or do I drop it to be at the lowered ride height?

Also I am a novice welder and I am thinking with the risk of warping the housing I am going to pay someone to weld this up for me.

Just trying to do things right. the first time if possible. Thanks guys

 

[Brian Thompson]

Put the second bracket at the same angle as the factory one. I used a long piece of all-thread going through both brackets and tightened nuts on each side of every bracket hole to get mine lined up.

 

[62ImpalaSS]

Thanks Brian I just got a notice that the bracket shipped via Ups so that will be a project here soon.