3 inch "Z" or 3.5 inch?

[Realnoisy]

Originally Posted by chevyrestoguy

3"/3.5" is a bunch of "Z", and you might have issues in a few areas. If you're planning to use the stock steering box in the stock location, your steering shaft is going to hit the top of the driver's side control arm. The steering linkage might get a little weird, too. The idler arm may not be long enough to secure to the passenger side framerail because it's now 3" to 3.5" higher than normal. If you're not running the high hump cab, you're going to hit on the transmission, and you'll need to build a new tunnel. You're going to need to build another trans crossmember, or space your current crossmember up a whole bunch. You'll have to keep an eye on your driveshaft angle and space up the carrier bearing. I'm not sure, but you might be real close on the brake booster and the heater box if you try to get the valve covers off. You'll also have to get creative on the front sway bar. The stock front sway bar brackets on the frame are too low in relation to the 3"/3.5" height change of the lower control arm attach point, and the sway bar will be at a downward tilt and won't be in it's optimal location.

After a lot of figuring, we decided that a 2" Z gave me the extra crossmember clearance without a whole lot of hassle. I will have to put a very small c-section in the upper control arm for steering shaft clearance. I had to redrill one new hole in my idler arm so it would bolt up. I removed the front sway bar hangers and bolted the mount saddles directly to the frame. I have a high hump cab, and I have plenty of trans clearance. I had to build 2" spacers on my trans crossmember and I also built a shim for the carrier bearing to get the pinion angle back to stock. With a 2" Z, you can still use the stock inner fenders if you trim the bottoms.

If you decide to Z the frame, make sure you move the whole assembly forward 1" at the same time to center the wheels in the wheel openings. The farther you lower a 60-66, the more the wheels move back in the wheel openings. A 1" change in the wheelbase makes a huge difference in appearance.

Z'ing a chassis gives you a lot of great features for hardly any money at all. In this case, more is not always better. You can send yourself down a rabbit hole where you wind up modifying everything, and it may get to a point where you regret your decision.

If your ultimate goal is to lay frame, you might want to consider that the rockers and bedsides hang way lower than the frame. If the body hits the ground first, then laying frame is a moot point.

I went with a 3" Z. So far, everything you describe plus...hood lip clearance on tires when closing hood...which means you'll have to narrow the track, or trim your hood lip, or have some serious negative camber. Also, if you're running a manual transmission, your clutch pivot z bar will have to be addressed. I already moved my xmember up the rails 1 inch to center the wheels so I just made a vertical cut. The radiator will have to be addressed. I use knuckle joints for steering to clear the drivers side upper control arm instead of notching the UCA. I just went outside and looked at my valve covers, I should have no trouble taking them off, but I'm very close to the brake booster as you have pointed out and I'm not running a heater box. I moved the engine to the V8 position and now have some good dizzy clearance. I've already purchased a high hump and will be addressing all that you have described. When I air out, my frame barely touches the ground. This is with 1.5 pancaked xmember (all the steering linkage, steering box, idler arm and centering in the wells were addressed at this time with the pancake) and 2.5 dropped spindles with bag cups trimmed to 1.5. Before I forget, you will have to remove the stock bell housing xmember because it hangs low and will hit first preventing you from laying frame.

I just installed the engine and trans (T5) today. I had to remove the ebrake linkage on the ebrake xmember to slip it in. In the next few weekends I'll be addressing the low hump and trans xmember and front sway bar.

I'm sure PB will get a plug on this thread by someone and that's okay but I prefer to build a "glue together" instead of a "snap together" model. I enjoy the build so far even though sometimes it feels like it will never end. It's a journey of meeting people, searching for parts, using engineering and mechanical skills. So far, it keeps me of the streets....literally!

[chevyrestoguy]

Originally Posted by Realnoisy

I went with a 3" Z. So far, everything you describe plus...hood lip clearance on tires when closing hood...which means you'll have to narrow the track, or trim your hood lip, or have some serious negative camber. Also, if you're running a manual transmission, your clutch pivot z bar will have to be addressed. I already moved my xmember up the rails 1 inch to center the wheels so I just made a vertical cut. The radiator will have to be addressed. I use knuckle joints for steering to clear the drivers side upper control arm instead of notching the UCA. I just went outside and looked at my valve covers, I should have no trouble taking them off, but I'm very close to the brake booster as you have pointed out and I'm not running a heater box. I moved the engine to the V8 position and now have some good dizzy clearance. I've already purchased a high hump and will be addressing all that you have described. When I air out, my frame barely touches the ground. This is with 1.5 pancaked xmember (all the steering linkage, steering box, idler arm and centering in the wells were addressed at this time with the pancake) and 2.5 dropped spindles with bag cups trimmed to 1.5. Before I forget, you will have to remove the stock bell housing xmember because it hangs low and will hit first preventing you from laying frame.

I just installed the engine and trans (T5) today. I had to remove the ebrake linkage on the ebrake xmember to slip it in. In the next few weekends I'll be addressing the low hump and trans xmember and front sway bar.

I'm sure PB will get a plug on this thread by someone and that's okay but I prefer to build a "glue together" instead of a "snap together" model. I enjoy the build so far even though sometimes it feels like it will never end. It's a journey of meeting people, searching for parts, using engineering and mechanical skills. So far, it keeps me of the streets....literally!

Wow, you have done your homework! I am impressed. You have given this mod some real thought. I'm definitely tuning in on this build!

I COMPLETELY agree with your last paragraph. Don't get me wrong...I love Nathan Porter's stuff, and if I was building a high-end vehicle, I would use his parts. I've always been a guy who would rather crawl through a wrecking yard or hit the swapmeets to build my vehicles. I love making things work out of parts that most people don't give a second glance. If I see an article on how to build something for $500, my brain starts spinning and I'll figure out how to build something even nicer for $200. It's the way I'm wired. I've tried to keep that same theme during the build-up of my '64, and it has been one of the most fun projects I have ever done.