The Stovebolt Site Forums The Shop Area The HiPo Shop Sub frame question

I have a 50, 1/2 ton frame that has been sub framed.I have been told by a chassis mfg. that the sub frame is too wide and that it should have had a Mustang 2 assembly. The width is 60-61" and the hub to hub on a 3100 is 56" (?). What have you guys done in these situations-wheels,narrowed a-arms ?
Thanks

My 54 is running a 62" mount to mount on both front and back but I'm running the straight axle on the front....235/70/15's on 7" rims with 4" back spacing on the front and 255/70/15's on 8" wide rims on the rear, also with 4" backspacing. Both front and rear sit centered in the wheel wells and the front has ample clearance (5/8") with the tie rods....both stock and upgraded.
I probably could have run a 3-1/2 to 3-5/8" backspacing with no inside bed and outside fender issues.

As Joe mentioned, folks are quick to sell you stuff you don't really need. The 3-1/2" rim is pretty common and most tire dealers who sell rims will let you try out a rim/tire combo. Eastwood also sells a $20.00 rim/tire fitment gauge that lets you dial in exactly what rim and tire combo will look right on your truck.

Dave

I believe 62" is what all ADs have between backing plates. My Camaro 10 bolt is 62" and fits well between the fenders.

The rear is OK. It's the front end that they are telling me will have steering problems,especially if I drop the front end. This is a small block motored truck with PS.They make Mustang 2 and narrowed control arms. The sheet metal is off the frame so it is hard to tell where the tires will fit in the wheel well. I was planning on running 15x7 wheels.
Thanks

Its time for a mock up. Put the sheet metal back on and make sure you like the fit and the look.

Given the money and work required to find a new frame and then put a Mustang II on it, it would be worth a little more effort to see if what you have will satisfy you.

But before choosing the Mustang II approach take some time searching here and other places to get a good picture of how happy people are with the various Mustang II and other IFS options.

There are no magic bullets, all the options I am aware of have both advantages and disadvantages.

Thanks. I really do not want to go the Mustang 2/old frame route,if I don't have to. I was hoping someone would respond that had the same situation and give me their experience with a sub framed 3100. I know that Fat Man makes a narrowed control arm kit that will give a few more inches side to side. I am trying to find out if I really need it.
Thanks to all that have responded-I really appreciate it.

On the Camaro subframe use 15"x6" rims with a 4 " backset and 205/75/15 tires and you'll me fine with tire clearance.

Thanks for the info. What wheels did you use?

Ralley rims (15" Chevelle style). Got them from Wheel Vintiques. Cost around $60. each.

Thanks Wbrowne. Hard to find any polished aluminum wheels with a 4" offset. Anybody have any other recommendations or suggestions?

I am using the IFS front end and rear end from a 78 Chevy truck. I narrowed the crossmember 1.5", but it was still too wide. The bolt pattern on these later Chevy trucks was 5 on 5. I found that the late model Jeep aluminum wheels (17 and 18") have really deep backspacing, are 7.5" wide, and have the 5 on 5 bolt pattern. The 17" wheels I got hit the lower control arm when I dropped the front where I wanted it, so I had to modify them some.

If your bolt pattern is different, just surf Ebay to find a stock rim with the right bolt pattern and backspacing.

Most wheel suppliers will sell you wheels with any offset so order away. A mustang 2 front suspension is not a truck suspension, it is a SUB-compact car suspension. Also, remember Mustang 2 sounds better than Pinto and all Mustang 2's were nothing more than a pinto with different sheet metal. A M2 and narrowed control arms would be a waste of cash and would be a travesty of truckism.

There are better ways to get IFS and keep load capacity and safety. Quit talking to the folks you are talking to.

Do you know which stub is grafted on to your truck? Is it a camaro, C10, S10?

I think it is a late 70's camaro. I have the part numbers off of some of the suspension pieces and am checking with a GM dealer this week. My hub to hub is 61.5" I saw where there are disc brake kits that will give 2" more clearance. I need to see if their kit will work on my sub frame.Any idea where they are getting the parts-what year GM??? has narrow rotor hubs?? The company is ECI.
Thanks for all of the help.

hey scott , i also have a 49 p.u. , and have had enough of the stock steering straight axle , you say there is a better way than a mustang II ?? what it is ?? fabrication is not a problem ,thank's steve

How about the thin rotor assembly that ECI sells-says it picks up 1" per side? Anybody use these?

The easiest IFS swap is here

Scott,unfortunately I purchased this truck with the sub frame already grafted. As I learn more about the front end of the trucks I realize that the subframe is 5" wider than the stock 3100. Now I have to figure out what the best move is to gain back some of the space. Off set wheels,narrow rotors and shortened control arms seem to be the options at this point. I am trying to get input from those that have run into the same situation. It will work the way it is now but,I can't lower it and expect have a tight turning radius. I don't want the tires to rub.
Thanks

Sounds like you need to find a set of Big-bolt front fenders to widen the sheet metal.

Big bolt front fenders are bigger so that presents whole new problems, you really don't want to go there unless your gonna build a 4X4. The big truck fenders have larger wheel openings, way larger than your rear fenders as well as the grill and hoods are different.
Mongo

The other approach is to use a second set of standard size fenders to widen the original set. Determine how much wider you need to be, then slice both fenders length wise, making sure to leave the additional amount on one of the fenders, then weld the two together.

Probably a lot more work to do than to describe...

I'll confess I've seriously considered this approach more than once and even have a few extra fenders just because I expect some day to actually do it.

Here is my half ton 3100 with a set of 6400 fenders bolted to it (actually the whole front clip). If the fenders were that much longer, shouldnt the radiator support not fit? The front radiator support lined up fine, and the only issue was the fasteners on the inner fender on the drivers side didnt line up between the 48 cab and 53 clip. When I lined the fenders up to one another, the big bolts were wider and had a slightly larger wheel openning, however I did not notice any length difference.

Also I am including a shot of Frankentruck with a complete 6400 cab and front clip sitting on an S-10 chassis.

http://good-times.webshots.com/photo/2062240040101989507adCmwZ

http://good-times.webshots.com/photo/2506222090101989507ZfRXBO

I stand corrected, this morning I measured from the small rib above the firewall indention to the outside edge of the core support on big red (my 53 2 ton) 33.5 inches and the same spot on a 50 1/2 ton 33.5 inches.
The big truck hoods are different as are the grills.
Mongo

I found that the big truck grills are taller. However I have a 1/2 T grill in the Frankentruck photo above (top bolts lines up, lowers dont)

Mongo, what is the difference between the hoods? I havent tried to swap hoods yet, however I have 2 big bolt hoods and one 1/2t hood.

We prob. should spin this to a new thread so as not to Hijack...
The big hoods are shaped different. Specifically at the back corner, the big trucks come to more of a point, than the little trucks, and the curves are different where they come down to meet the grille. http://www.mongosgarage.com/tech/hoods.jpg
The grille is quite a bit different, each bar is taller and the side and center supports on the back of the grille are taller.

I have a really nice 52 GMC 1.5 Ton front clip (Minus Grill) setting aside, I have had thoughts of mating it to a 48 Panel I have and setting it on my 89 4X4 Suburban drive train. But that's pretty low on my priority list of projects plus the suburban really has nothing wrong with it the way it is at this point.
Mongo

Heidt's makes a 1" narrowed tubular control arm for the Camaro and it uses the factory ball joint.

If I read corectly you said you believe the subframe is from a late 70's Camero. If so, that is the most popular swap and you should not have to buy special offset wheels or change any of the suspension parts. Everything should fit just about perfect provided the fabrication for the subframe was done correctly. Just my 2 cents but I do have 2 of them done that way and they are fine.