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nigelman 09-08-2004 06:29 PM

IFS Swap question
HElp me out guys. I am installing an IFS from a 81 1/2 ton chevy onto my 53 frame. The difference is about 1 1/2 inches. Now, should I use two 3/4 inch plates to take up the slack OR cut out 1 1/2 inches with a plasma cutter out of the main support brace and weld it back together? Any help will be appreciated.
Fred in Pomeroy, Ohio
53 1/2 ton Chevy
36 Farmall F-12:

advanced design 09-08-2004 08:43 PM

Hi Fred,

Just a thought, will the front end be too wide for the fenders to fit properly? Some trucks end up with the front fenders radiused which doesn't look quite right or the tires stick out past the front fenders. Dunno, might work OK on this application.

I think your question is regarding narrowing the subframe. If you do narrow the subframe the centerlink will have to be narrowed the same amount. My vote would be to plate the difference and not narrow the subframe.

Happy Building!

astroracer 09-09-2004 06:46 PM

I have to agree with Adv. Des. Make the frame fit the suspension BUT, like he mentioned, verify track width before you cut it up too much. Measure the distance between the wheel mounting surfaces on both vehicles. If the '81 is too wide you can usually compensate a bit with a positive offset wheel. Keep us in the loop.

nigelman 09-09-2004 06:53 PM

The only problem with plating is the lower holes end up on the curve of the frame. I am leaning toward the cut out and shortening the center link. Next question is : This will raise the stock height about 3". Should I cut the springs down or find lowering springs? And where do I look for those?
Too many decisions. I am going to the Springfield, Ohio swap meet manana. Maybe I can find them there.

astroracer 09-09-2004 07:01 PM

If you narrow the '81's K member this throws ALL of the suspension geometry out of whack... Handling will go out the window. Bump Steer, Ackerman, Roll Center Height, etc., etc. will all be effected badly. The vehicle won't drive right and you will have a hell of a time getting it lined up...
I would suggest forgetting the '81 full size and looking at an S10 front suspension instead. It will be much closer to the track width of your '53 and you should be able to install it without cutting it in half... Install the whole front frame section from the firewall forward.
There is a ton of aftermarket stuff available to lower the s10's also.

nigelman 09-09-2004 07:23 PM

Not sure y the performance would be so radically affected. This requires taking out 1 1/2 inches from the K?.
There is another article in the knowledge base about this same procedure. Again, I am not sure which way to go.
Thanks. Your opinion on these articles?
Easy IFS Upgrade (

advanced design 09-09-2004 09:52 PM


Astroracer brings up some very good points to consider. Interesting article there but I noticed the author doesn't address narrowing the centerlink. If the centerlink is narrowed in the center the exact same amount as the subframe bumpsteer shouldn't occur (as long as the upper control arm bushing, tie rod joint and lower control arm bushing are in the same plane as engineered by GM).

Camber and caster should be able to be brought into align if the horizontal and vertical planes of the control arm attaching points were not changed from original. I think that is Astroracers point. Changing the subframe width can radically effect geometry.

The article states this suspension will raise the truck 3 - 4 inches higher than stock height, then you'll get dropped spindles and perhaps springs to get the truck a little below stock height.

Just a few more thoughts - This change looks like some skilled fabrication and welding are needed, if you can do that, great, if not that fabrication talent cost's $. The spindles and springs will cost additional. If you haven't already cut the frame have you compared using a Mustang II based unit cost to the costs (spindles, springs, disc brakes) and additional work of this subframe?

I certainly don't want to dissuade anyone from being creative and resourceful in their build but want to assist looking at issues and options.

Have fun

nigelman 09-10-2004 04:11 AM

Thanks for all the input. What is "bumped steering"? I have checked on prices and can have the work farmed out for about $35 at an auto alignment shop.
Will let you know the vertict. What about cutting the existiing springs about a coil?

EBlack36 09-10-2004 07:00 AM

One of the big questions is what are you going to do with the truck? If you are going to do it in a street rod style, the that front end is way too wide and you will have a have time getting it down to where you want it to be. If you want to get in into the weeds, a mustang II or the s10 may be the way to go. There a multitude of options including making it a dually.

advanced design 09-10-2004 07:01 AM

Bump steering is the vehicle will steer one way or another when the front tire encouters a bump. If the tie rod joint at the centerlink is not in the same plane as the upper and lower control arm bushings the tie rod will swing in a different arc than the spindle, As the spindle goes up and down the tie rod will effectively push or pull the steering arm in or out.

I wouldn't cut a coil as lowered springs are available but if you do do not use heat to do so. Use a cut off wheel.

Hope that helps.


nigelman 09-10-2004 06:59 PM

Thanks for the input. Can you direct me as to where to look for lowering springs???
I talked to a fellow at the swap meet who did this IFS swap and had no problems with steering. Jut another opinion

poncho62 09-10-2004 07:02 PM

Find a subframe that is the proper width. I used one out of a 76 Nova in my 51.....worked out just right.

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