looking to do a sub-frame mount from a 1984 firebird into/onto my 1951 suburban. I will be putting a Cadillac 472 in it with a th400 trans. my question is about the k-member in the subframe. were they different for the variety of engines that was output by GM? or were they all the same. I cant find anything in my books about the sub-frames. any help would be great. thanks, scott
Yes, you'll need a rear sump pan from a front driver, or you can modify to fit,, and you'll need to relieve the driver side exhaust manifold to clear the steering shaft.
Not sure about your question.......if you mean 'were all firebird frame K members the same for a given model year, regardless of engine installed?", then yes, that is the case. you will notice there are usually several sets of holes to accommodate various engine mounts that were required, depending on the engine installed. Though you didn't ask, the strength should be fine as a Caddy 425/472/500 doesn't weigh anymore than a Pontiac 389. Ray
1984 Firebird would be a unibody with struts. To my knowledge, the only v8 ever factory installed in the 1982-92 Firebirds were of the SBC variety. Did you mean 1974?
yes. I did mean regardless of engine installed. thanks. and about the weight question. the 472 weighs in at around 625 lbs. the 84 firebird was available with the SBC, so the weight was another issue. I can swap out springs. I have not picked up this 84 firebird yet, was going to look at it tonight. $300 for the entire car. cant beat it for parts. I assume that these cars are also the subframe -type. maybe I am wrong on that. and for the oil pan, I was hoping it would not be in the way, but you are probably right. I know I can pick up an eldorado driverside exhaust manifold which will clear and the oilpan has a rear pickup.
I'm pretty sure that the suspension on an 84 Firebird is a strut style suspension that isn't anything near what you want to subframe your truck. I went to the O'Reilly site http://www.oreillyauto.com/site/c/d...&model=Firebird&vi=1251212&pt=C0077&ppt=C0035 and confirmed my thoughts. The 84 T/A uses struts and is useless to you for a subframe swap. You need a first or second generation subframe. The second generation front steer (mullet) Camaro an Bird subframes are usually the most popular to use.
There is no removeable subframe on an 84 Firebird. Why not go to FatMan and do an MII based conversion without cutting up the stock frame?
thinking the same thing on the front sub as everybody else an 84 is most def. not what you want at all... Look for an early camaro/stang sub.. or a MII which would be a hell of alot easier and you can buy one thats tailored for your needs....
The '84 should still have a sub-frame. For the size of the vehicle, I'd be more inclined to go with an aftermarket conversion or graft on a GM metric clip. Bob
No the 84 Firebirds and Camaros are a unibody construction that run struts. They still had steering boxes rather than r&p but unless he wants the brakes and rear end there isn't a lot he can use on the burb suspension and chassis wise. The GM metric units would work though and are plentiful and cheap.
Ya learn something new every day. I like the GM metrics myself, lots of parts available for them and loads to pick from in the bone yards. Bob
I used a '78 Tran Am sub in my '55 Cadillac...and put a 500" Caddy engine on top of it and then a T-400 tranny behind that...it's plenty stout... Go here to see the build: http://www.jalopyjournal.com/forum/showthread.php?t=329070&highlight=the+best+55+caddy+build R-
Seriously look at the GM metrics long before the 2nd gen Firebird for this swap. The Firebird Camaro stuff is just too wide for these cars at around 61" wide. The metric clip is right on 58", much closer to what you need. All in all, I would still do a MustangII long before a clip.
The earlier subframes are better,around 68-74 I think, with a rear mounted steering box.They give you a lot more room for the radiator and the steering box lines up to the column a lot better.I have used both and recommend the earlier.And yes it will work with the Caddy motor and trans with a rear sump oil pan.
thanks guys. as always, lots of good information. the only reason to swap over (subframe) was cost vs. a fatman chassis. also looking to use the rear end, brake master cylinder, steering column, etc. looks like I have got some thinking to do. I will keep you guys posted with the build. thanks.
The desireable years for the Camaro/Firebird clips are 70-79. Certain Firebirds had 455s, so your Caddy would be fine in the weight department. These clips are pretty beefy, much more so than a MII conversion and alot cheaper. As far as track width, they work well on the later 50's trucks, not sure about track width differences on the earlier Chevy trucks, but as mentioned, might be too wide. Here's a tech by Lux Blue on clipping a later 50s Chevy, maybe you've seen it: http://www.jalopyjournal.com/forum/showthread.php?t=148978
70'-81' camaro's/firebirds, 75'-79' nova's/apollo's/omega's all have subframe that only differ slightly (frame horns for bumper mounting). we put a 500 caddy in a 78' Z-28 and it was fine with one issue being hood clearance.
i used a 1977 impala front end in my 1951 ford p.u. it's holding up a 6bt cummins. still using stock small block springs.
more ideas. I love it. keep them coming. What I am looking to do is get a more updated front end and get a better matched rear end for the 472 and th400 that can handle the torque. I will have to look into the other vehicles mentioned as well. another thought was to just weld up the mounts for upper and lower control arms for the front end and just buy a rear end rather than sub-frame it. anybody want to chime in on making the control arm mounts vs. subframe? pros vs. cons? thanks. scott
The rear suspension on the 82 and later F cars is not hot rod friendly. The rear end has four mount points, two lower control arms,. a transverse bar to limit side to side to side movement, but now the problem. There is a long beam that attaches to the rear of the transmission, called a axle torque arm. This serves to replace the upper control arms. The trans extension housing was a Firebird/Camaro oddity, with provisions for mounts on the side. TH400's were never put in these cars, so you would be trying to fabricate the rear mount to the transmission. Coupled with the differential's small size, 7.625 and 7.75, the rear axle IMO would be borderline in strength for what you want to do with it. You could probably use the axle with a aftermarket four link kit, or fab up brackets and use longitudinal leaf springs on this car, but IMO again you would be better off using a Gen 2 Firebird/Camaro rear end at minimum.
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