Having never sub-framed a car before, I was wondering about a few things...since that's the way I'm looking to go with my 49 Chev. It seems pretty basic...lop off the front portion of the stock frame and connect the donor car sub-frame to the old perimeter style frame making sure to position it so that the wheelbase is correct and that it is centered in the vehicle. Is it neccessary to install braces such as I've added to my crude drawing here to help triangulate the front sub-frame and make it stronger? I don't know that the stock firewall could handle MUCH stress. but this design really SHOULDN'T tax it too much, unless the front of the new chassis really flexes, right? (Those bars would also help to locate some of the components needed to button up this swap, so even if they don't add support, I may still need to run 'em). Being that stock sub-frames just bolt to the floor of a uni-body car, they must be rigid enough to handle being thrown onto the front of a frame in this manner, right? (No way the floor of this particular car could handle anything of a structural nature being bolted to it...so that is out of the question!!) Also...is it "okay" to angle the sub-frame upwards a few degrees to drop the front of the car some without altering the stock donor car suspension? (Assuming that any driveline angle issues were addressed). Seems like that would help get the nose down low...and since you gotta connect the new sub-frame to the old frame anyway...why not mess with the angle a little before welding it all up? Is it really as simple as it looks, or did I overlook something here??? (Besides all of the rotten tomatoes I'm gonna field for sub-framing an old car to begin with...it just seems like an easy, low buck way to get an updated drivetrain, front braking system, and better steering and suspension all in one sorta neat package!) Tips? Comments? Death threats? Marrige proposals??
[ QUOTE ] Marrige proposals?? [/ QUOTE ] There's that Gay Michigan love thang again. Seriously though, you MUST stop by the house and pick up a copy of exactly how Big Olds was subframed. I've got not only that but now they did the custom motormounts for subframed "rods" and I'll also include a copy of hangin sheetmetal on Subframed rods too. About 20 pages in all with not only step by step instructions but pictures to boot! I'll put it in the milk shoot next to the side door.
yeah, preety much that easy. dont think youll realy have to have those trianglulated bars for anything other then finding a spot to mount stuff. and if you "angle" your clip your going to have to rebuild the motor mounts so the angles correct--like you mentioned already. why wouldnt you just step the frame at the firewall, then yo have your drop and dont have to re work anything else? im sure some one got pix of there steped subframe later tim
You shouldn't need the triangulated pieces. Not to mention they will be defeating the purpose of the body/frame rubber insulators. Angling the frame upwards a degree or two may be ok, but there's a possibility you could run up against a caster problem when doing wheel alignment. Problem as in, not enough adjustment range. As a reference, the 32 Ford frame has a two degree kickup just under the cowl. It does help in the drop dept, but I've never measured it. I think you could get it as low as you want by how high you place the donor car front end with front section level and matching the original frame angle. This seems to be the common way to do it.
FH,put it in level and if you need to get it lower cheap,I know of a different lower balljoint to run that will drop it an extra 1.5" .If you go to www.canadianrodder.com site and then go to the forum ,discussion/chat board FatChuk shows exactly how he clipped his 50 chebby with a pinto/mII frontend the cheap way.........Shiny
I wouldn't change the angle of the sub -- the way most subs are designed, you can vary the lowness of the finished product by changing where you make the graft, fore-and-aft. Most of the popular subs/grafts (Nova, Camaro, 80s Cutlass, S-10) have a kickup from the frame legs to the suspension. Set the sub up to its original stock height/angle, and set your car's frame to the ride height you want. Make the splice wherever the two overlap -- the further back you make the splice, usually the lower the finished product. One caveat though -- the metal of your Chevy's top-hat style frame is pretty thin (except for the bottom plate). I've heard of several instances of subframe grafts cracking the old frame where it's welded to the sub. You may be able to avoid this by adding some reinforcing plates over the graft -- with a good overlap and maybe some rosette welding besides, it should end up strong enough. Steve.
My dad and a buddy did one years ago on his 49 coupe. They used a 69 Camaro subframe. Instead of a butt or overlap installation, the split the welds on the lower end of the subframe and made it narrower. Then they heated up the old frame to get it to expand a bit and slid the subframe iside the old frame. It turned out pretty slick.
FH, anytime after I get home at 6pm, it will be in the milk shoot. You can pick it up anyday, anytime after that. And just incase you didn't realize it, all the work and articles written, that I'll be passing along, were done by the HAMB's very own Just Steve, Big Olds's daddy
I did this to my 40 chevy using a 72 Firebird TA stub. It works great. As C9 stated you do not want to angle it or you will run into caster problems.Where you weld the two frame together will give you your ride height. You never said what stub you plan on useing. GM has front and rear stearing units. Mine is a front, had to trim and box out on the radiator saddle for sector clerance and also uper cross member for fuel pump to clear and also to remove it with out pulling the motor. I sure if you get that info from Denise you will do just fine. Just Steve has better delivery ( and spelling) than I do.
the only thing i can add is that the 70's camaro frame is wider than the nova. if you use that type you may have to use offset wheels. if you use early nova or early camaro you have to fight the disc brake deal( finding them) the next time i will use a mid 70's nova with disc on it already. the biggest thing is to get the frame square and the wheelbase correct, after that it's a no brainer. well low brainer anyway.
Just a word of caution... If your state is nit-picky about the original frame number for registration purposes, you might think twice about loping off the part of the frame that as it on it. otherwise you might find your car impounded? if it's ever checked by an officer... It's on the top of the left frame near the axle on a lot of cars and trucks.
[ QUOTE ] If your state is nit-picky ... [/ QUOTE ] Nahhh. We're here in Gay Ass Michigan, which automatically makes us gay, but we can do damn near anything to our gay cars without trouble. Nothing like those Nazis running California!
fathack a 52 chevy? I think chassis engineering makes a bolt in mustang 2 crossmember for that car.. and if so it has ride height adjusters built in.. if it were mine ( and its not...but) Id NOT subframe the car because it will make reattaching sheetmetal and other "related accessories" difficult later.. just my 2 cents.. good luck oh and I know it would cost more upfront to mustang 2 it.. but what if you end up too low? or with the wrong wheelbase or somethin else goes wrong with the graft.. then your shafted.. later sawzall
Fathack - I'm with Sawzall. There are a number of Mustang II crossmembers that can get you what you need. You don't want to do this yourself unless you have someone with experience to walk you thru it. Along with Chassis Engineering, R&B's Obsolete Chevy parts has a slick bolt in Mustang II crossmember that uses the factory holes that bolt on the '49-'52 Chevy front. I've seen it and it is a real easy way to go. Another alternative if you need to do it on the cheap is to cut the complete crossmember from a Mustang II. I've seen everything you need at swap meets for $50-$100 bucks. I have personally grafted one of those to a '52 Chevy a few years ago and it is much less work than installing a complete clip. With a Mustang setup, you don't have to worry about Sheetmetal, Bumper, nor Radiator mounts. Good Luck! Reggie
I have to agree with 1Low, there are alot of kits available for mustang II front ends, and most of them are getting to be reasonably priced. I used to have a 55 pick-up that was subbed, it worked out great, but the mustang II seems to be an easier swap...less headaches.
fh, 1. i don't care one way or the other about M-II or subframe, but my friend johnny put a fat-man M-II under a '48 chevy and if he can do it anyone can. he's a great body man but vigorously hates mechanical things and bracketry. i don't know what the differences are in 48 & 49 frames. that was the "big" change year, but i'm sure that the fatman (and other mfgrs.) kits all work pretty much the same on the frame they were designed to fit. that being said; 2. i sold the car before i subframed it, but i had scoped out a subframe on my '39 buick at one time. my plan was to measure a running, stock, '69 nova (what my subframe was from) subframe at several points when it was sitting flat, level, and at stock ride height. i mean from the ground up to these points. then i was going to use all-thread in place of the shocks and tighten up against the subframe springs until the a-arms were parallel with the ground. or at least at the same angle as the stock nova i was going to measure. then i was going to block up the subframe at the pre-measured heights. this would have been without the wheels/tires, of course. this gets the subframe geometry to where the factory intended it to be, caster included. then i was going to block up the car at the ride height and rake i wanted and marry the two together. unless i missed something of great importance that would have given me the stance i wanted, the suspension travel that i needed, and the front would have been easily aligned by any alignment shop. i would have changed out the coil springs if they were too stiff or soft or didn't ride at the correct height. this make any sense or add anything that hadn't already been mentioned?
Did my 50 Buick years ago , first time I had done it, came out fine. Only two things to add. There have been tons of articles written about this, and all stub projects are similar in scope and difficulty. I would read all you can before firing up the torch. Once the front end of my Buick was cut off and lying on the floor I had a mild panic attack, but got over it and finished the job. Denise's info sounds like it will be priceless. Second Measure often and use gussets. Better overengineered than broken on the road. You can do it!
Fat, Steve is right about how thin Chevy top hat frames are. Just sheet metal. Our 41 Olds has the same basic front end as the Chevy. I added a GM center steer rack, disc brakes, dropped spindles and tube shocks, and MII V6 springs with 1 1/2 coils cut. It drives better than any MII equiped rod I ever drove. Just another thought, to confuse you some more! hehe
A 49-54 chevy is pretty narrow for a front-steer subframe unless you narrow it. I narrowed a front steer for my kid's shoebox and the only problems encountered were restricted exhaust manifold clearance and the steer box gets real friendly with the radiator saddle. Both problems overcome with a little work. We used a cross-flow radiator mounted above the steer box and hadda use block-hugger headers on the 400 sbc but we got the front tire clearance we needed....narrowed the sub 3" and used skinny front runner tires...
Where ya gonna do this Greg? If it isn't too far a stumble home, I'll help ya out! I would like to learn this too. A swap like Kev's is wayyyyyyy too much work for a lazy boy like me!!!!!!!!!!!! Jay
I've read that the top hat style frames were meant to bend a twist all together and when you subframe one, the subframe doesn't twist with the original and puts a lot of stress on the frame right behind the weld. Not saying it can't and hasn't been done well, but I've heard that mustang II is the way to go.
If it was mine I'd set it on a s10 chassis. I like the sub in my Stude, but in the long run I would have saved time and money with a chassis swap. I'm running mine so low that tire clearance is an issue. Just something to think about before you cut things up.
Hack- If you sub it Rocky's right it needs narrowed some- also remember that if a line is drawn down the center of a rear steer sub[frt to rear] the frame rail on drivers side is further from centerline than is the pass side rail-so you center it by triangulating from a given point on the orig frame to the upper balljoints etc as a point of reference-NOT THE RAILS THEMSELVES.....Now I would not recommend a sub[altho ive done a shitload] AS the orig front end is great if you add a vega or camaro/nove [manual]STEERING BOX....REMOVE THE BELLCRANK AND TOSS IT- THEN USE THE ENTIRE STEERING LINKAGE SIDE TO SIDE INCLUDING THE IDLER ARM FROM SAME CAR [BOX IS FROM].[butt simple] and looks a ton better than a sub job.plus its trad!
I'v sub framed a couple of mine and it works great...everybody has pretty much covered the topic here but If I was to do another old cheby I'd put a monte carlo frame under it and use the whole thing...have to change the outer perimiter rails but thats simpler than all the sub frame measuring and fit...the metric cars are also narrower and fit the fenders better...all new brakes, gas tank, exhaust, anything you want you can buy over the counter...my two cents worth
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