Rear Leaf Spring Help Needed

[mudjnky]

This is kinda long, so thank you in advance for reading it and any help or advice offered. Everyone here has been a big help with all of my questions so I'm hoping you can help with this one. We have a 68 Camaro Baldwin Motion replica. It has the GMPP 454/450 roller engine, M21 and 12 Bolt w/4.10. Heres the situation: the prev owner setup the rear with mono leaf springs and the perches are in the wrong spot causing the springs to be pulled inward. They are also twisted into an "S" pattern. He also added traction bars and moved the shocks inboard of the springs. There is a bracket welded into the trunk floor for the upper shock mounts. The traction bars are the type that have the long "U" or "J" bolts to adjust the preload. Now the right side of the rear is sitting further forward than the left.
Ok, here is my question: I purchased multi leaf springs, new perches, and install kit. In the install kit there are pads for the top and bottom of the springs. Why? Seems to me that would allow too much deflection in the mount. I'm used to setting up 4WD springs and they are always metal to metal, anything else is a no-no. Is there a way to eliminate the pads? When I bought everything the guy said some people run a mono leaf perch with multi leaf springs. I don't want to do this twice and definitely don't want to do it wrong. What's the best set up?

[Chevy454]

You can ditch the pads if you want to...if you're planning on running the car you might wanna take a peek at your pinion angle once you get it buttoned up...

[WILMASBOYL78]

Curious about the motor..is that alum or steel head version?
How does it run?? I have one in m 68 car and it needed some "massaging" to make power. http://www.yenko.net/ubbthreads/images/graemlins/rolleyes.gif

wilma http://www.yenko.net/ubbthreads/images/graemlins/flag.gif

[mudjnky]

It actually runs better than any other performance engine I've had. Steel head, everything was set up on it when we got it. Cross Ram with Edelbrock 600 or 650, not sure.

[WILMASBOYL78]

Cross Ram??? do you mean an aluminum hi-rise single 4bbl manifold or does it have 2 carbs?? Edelbrock carb 600-650 would be a little small for that motor, but if it works..ok http://www.yenko.net/ubbthreads/images/graemlins/biggthumpup.gif The steel head BB GMPP engine is rated at 425hp..their alum head is rated at 440hp. Thanks for the feedback.

wilma

[mudjnky]

Cross Ram, 2 4bbl Carbs side by side

[mudjnky]

Heres a link to a picture of the car, I'm at work so i can't attach any pictures.

http://www.edselmotors.com/yenko2a/moreyenko014-tb.html

[WILMASBOYL78]

http://www.yenko.net/ubbthreads/images/graemlins/cool.gif http://www.yenko.net/ubbthreads/images/graemlins/cool.gif http://www.yenko.net/ubbthreads/images/graemlins/cool.gif

wilma

[mudjnky]

When my engine guy calculated everything it is supposed to make 450hp, you are right, 425hp out of the crate, sorry about that.

[scuncio]

I just went through a similar scenario. I eliminated the top pad (between perch and spring), installed 1" lowering blocks from Guldstrand on top of each leaf pack, and reused the lower pad between the shock mount and leaf pack. When I mocked everything up, for whatever reason, the RH pad didn't want to sit flat against the spring. I set the car up on corner scales and played around with shims until the cross weights were close. But I digress...
Here's my suggestion: if you don't want to cut one of the existing perches off and properly reinstall it so it's correctly positioned, measure how far it's rotated and use one of these between the spring and perch: http://www.speedwaymotors.com/xq/aspx/display_id.3354/itemNo.spring+leaf/qx/Product.htm

Hope this helps.

[scuncio]

One more thing: if the fore-aft location of the rear wheels is different from side to side, these lowering blocks allow you to dial it in perfectly: http://www.speedwaymotors.com/xq/aspx/paging.yes/dept_id.711/display_id.2153/qx/Product.htm

The circle track guys have some trick parts!

[mudjnky]

Thanks for the tips, I definitely have to replace the perches. They are welded inboard too far, someone did a hack job at some point. Even the welds are bad on them.

[WILMASBOYL78]

[ QUOTE ]
When my engine guy calculated everything it is supposed to make 450hp, you are right, 425hp out of the crate, sorry about that.

[/ QUOTE ]

I know this is a hijack but the crate motor stuff is interesting. GM claims 425hp with 163 intake and single 4bbl with headers...you have a dual quad setup..haven't seen a cross ram setup like that in a long time....I didn't think the motor really had too much with the big rect port heads and low compression: 8.75 to 1(advertised)..we put the 502/502 cam in and switched to alum heads(shaved slightly)..I still don't think it is all it could be, but it is fine for the street scene.

wilma http://www.yenko.net/ubbthreads/images/graemlins/3gears.gif

[mudjnky]

We're going to put in a bigger cam over the winter. I hope that will wake it up some. One more show in a few weeks then it all comes apart.

[WILMASBOYL78]

There was a great article a few years back in one of the magazines(Super Chevy or maybe Chevy Hi-Performance) called the "Frankenrat". It was all about this motor and some upgrades they did. The combustion chambers on those rect port heads are the size of the Grand Canyon..if you can get the compression up to about 10.5 to 1 and add some cam..you will make a lot of power. We also used the Edelbrock Airgap RPM manifold. We didn't change pistons..just milled the aluminum heads(oval port)..that limits cam timing because of valve clearance issues. If I did it again I wold just use the bare 4 bolt block and build from there. I will try to find that aticle and post it for you.

wilma http://www.yenko.net/ubbthreads/images/graemlins/3gears.gif

[mudjnky]

Thanks!