Ardent Fabrication Autocross Truck

arrg said:

You're going to want a quick ratio steering box after you wrestle it around the cones a few times. Can't wait to see some video of this thing in action!

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sewlow said:

Stock 400 steering boxes are a 14.4-1 ratio. The 454SS is a 12.7-1.
This will reduce the amount of turns down to 2.25 - 2.75, lock-to-lock, from the original stock box's 3.25 - 3.5.
12.7:1 ratio boxes found on some of the higher performance factory muscle cars from the 70s and 80s. The 1969-1976 Camaros, 1964-1976 Chevelles, Malibus and Monte Carlos used an optional quick ratio 12.7:1 unit. Gearboxes that were original equipment on 1983-1988 Monte Carlo, 1983-1984 Hurst Oldsmobile, 1985-1987 Olds 442, and 1984-’87 Buick Grand National, also have 12.7:1 ratio units.
Most of these gearboxes are the four-bolt mount but there are two different three-bolt mount gearboxes that were used as well. To keep things simple, all of the 1970 and later Chevelle, Camaro, Nova and Firebird have the same steering box bolt pattern as the truck's, so searching for these gearboxes eliminates any mounting problems. Aside from the mounting, all of these gearbox units are interchangeable.
Use the 400's factory idler & pitman arms with these boxes.
Another thing to keep in mind when interchanging between earlier and later GM gearboxes. The power steering hose fittings are not the same. Later fittings are metric with an O-ring incorporated, where the earlier gearboxes use the standard inverted-flare fittings.
You could search out an original Q/R box, identified by a 'YA' stamp on the end cap.
Or, there are a few aftermarket options.
Redhead makes a version, as does AGR, with a choice of ratios.
Use the power steering pump that mates up with the high performance steering box that you salvage. This way you are sure that the pump can keep up with the demands of the box.
AGR also makes a modified power steering pump to go with, which has custom porting & over-sized bearings.

I used a local rebuilder. Built with my choice of ratio. 12.7-1, of course. Same as the SS's. By using a local, if I ever have probs or questions, there's no sending away or waiting for replies.
I've also modded the original-to-my-truck steering box's presuure spring. (I should actually hunt down a matching Q/R factory box.) These pumps/boxes are way over-boosted for my liking. Especially after the Q/R box install. This is just a matter of clipping the spring in behind that puck in the high-pressure line attatchment to the box. I started with 1/4 of a turn removed from the spring. I ended clipping a bit more so that it ended up being 3/8 of a turn clipped. The F-body guys have been doing this for years. The minute details are fairly easy to find on those forums.

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ArdentFab said:

Thanks! Glad you brought that up, what's the way to go with the quicker ratio box? Does it come out of a certain car?

I actually want to develop a rack conversion kit similar to another brand I know.

I have two videos on YouTube so far, I'll try to share a link soon. Should show up if you search GMT400 Autocross Truck or something.

Sent from my SM-N960U using Tapatalk

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sewlow said:

I`m anticipating the R-n-P you`ve been working on. Eagerly! Lol!
The way-too-many links & pivot points in these trucks are problematic when it comes to serious handling performance. The steering feel provided is just too vague...along with the fact that they seem prone to eating themselves up.

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