Hey, I'm pretty new to the site. As the title says, I'm dropping a freshly rebuilt 455 and TH-350 out of a 75 LeSabre into my 58 Special. Plans to swap the rear end and fab a driveshaft are in the works. As there are two ways to learn things: the hard way or from those with experience, I was wondering if anyone has doen this swap yet and has some tips? Thanks
I haven't done that particular swap, but the '58 is a barge. Unless you do some serious beefing on the THM-350, I would recommend that you engineer the swap so that it is easy to change out the transmission, and keep a couple of good spares. The 350 can be beefed substantially, and is lighter and absorbs fewer horses then the THM-400, but for reasons of cost, I would still use the 400. That heavy car is not going to be a rocket ship no matter what you do. You will not break a good THM-400.
I'll keep that in mind. The car is a boat, but the doner car was even heavier. The 58 weighed about 4115 lbs off the assembly line and the 75 weighed in at 4350 lbs. Neither of them will ever be muscle cars by any stretch. I have an acre of room in the engine bay to work with. The only issue I can see so far is the 455's rear sump oil pan and the 58's cross member don't work well together.
Do remember that appearances can be deceiving. I am assuming that the engine compartment is pretty much the same as the '57. I know that assumptions can be dangerous, but there were some really tight clearances even with the Nailhead. (You cannot remove the rear couple of pushrods on the left side without resorting to hackery - or else removing the head with the pushrods and a couple of head bolts still in place). The 455 is wider - although perhaps not as tall. I would measure very carefully before beginning the transplant. It may be a piece of cake, but I hate surprises. I'll bet you do too.
I have to agree with John; that project is going to be tough, and appearances are very deceiving. Weld in a set of mounts and working the angles on a whole new driveline is an interesting preposition to say the least. Way beyond my meagre tallents. It might be more cost-effective for you to drop in a late (65-66) nailhead with a turbo 400; - you're probably going to have serious exhaust header clearance issues with that 455 along with the fact that the valve covers will probably be bouncing off the inner fenders. As for the sump issue, sorry, can't help you there; most 455s that I know were all rear sump; - not sure what you can do there. Maybe the B bodies had a centre sump; here again, not sure. Good luck; I'd love to see what a 455 in a barge like that could do...
Here is a really basic mock up of what it looks like now. The engine is too far forwad in this photo because I'm trying to line up the orriginal engine mount position. So I will have to move my mounts back. I just ordered some frame pads from TA. Once I start moving it back, the oil filter gets in the way. So I purchased a remote oil filter kit. But the furthe back I go I thave to wactch out for the steering rack. This is where the center sump that everyone has been mentioning may have to be used. I put the the rad support and wheel wells back on and there are no obvious clearance issues. I've deleted the old AC system and removed the heater fan and will be hiding the master cylinder. Headers will be another story. I have a set of Hookers which I have yet to test fit. Fun, fun....fun?
Just a thought. Why don't you put the '58 body on the '75 frame. Lots of issues now solved. May bring up more issues, but the up side is you will have a more modern suspension, disc brakes, a whole lot more options for suspension upgrades. Parts for '75 are far more readily available than most '58 parts & the '75 parts are usually less costly. Tom T.
I have seen a 57 body placed on a 72 Estate wagon frame. He left the wagon drive train AC, etc. in tact. It worked and gave the owner a more modern suspension and brakes.
The frame from the 75 is gone. I can get a 72 Riv' frame. I'm not sure how that would work out though. The 58 is a long car. As far as suspension goes, right now the plan is to order a custom built 4 link to go with a Ford 9" with disc brakes. Air bags all around. Would a front clip swap be a better option?
Sorry, steering drag link ou: Anyway, after playing around with the positioning a little bit, I don't think it will be a huge issue after all once the oil filter is relocated. I'm going to try the federal government solution for solving problems and keep throwing money at it :dollar::dollar::dollar: Here is a pretty good pic. Mine looks like that except really, really rusty.
A 58 Special has a 122 inch wheelbase while a 72 Riv has a 122 inch wheelbase. So it may work. I would use all the drive train including the engine , trans and rear along with the suspension.
I contacted the guy about the Riv frame. It's a 74 and not a 72 apparently. Still a 122" wheelbase so that is good. On the downside he already sold the rear end, so I'm back to the drawing board on the rear end. On the upside I have a Ford 9" with factory disc brakes in my garage. I was planning on using a triangulated 4 link to replace the other rear suspension anyway. So the frame swap seems do-able. Honestly, it will be a first, but sometimes the best way to learn to swim is to jump in over your head. Quick question: does anybody know if anyone makes drop spindles for the 74 Riv or if any other GM spindles will work?
I know that's the case in NC, but here is the still white north most cars are destroyed by the tremendous amount of road salt used each winter. It's not too easy to find a old Riv that hasn't been somewhat restored or already in the crusher.
So it looks like the Riv frame is a no go. Back to the orriginal plan. I'm going with the Ford 9" and I picked up a front disc brake kit from discbrakemike.com. I have a complete power steering set up out of another 58' that I would like to install and possibly some drop spindles from Fatman Fabrication. I'm looking into having the engine mounted by a local custom shop to save me a little agrivaation and to make sure that it is done right the first time. I'll post some pics soon.
You may want to find a 60-72 Chevy truck rear end and suspension and use that for your 58. It has trailing arm suspension, which works well in the torque tube Buicks. The Chevy truck is an open driveshaft type. As far as engine/transmission, I like the idea of a 65-66 nailhead with SP400 to transplant. Mounts will be the same up front. So locating the engine is a piece of cake. Also, in case your 364 is still viable, you can go with the 65-66 SP400 hydramatic, just needing the crankshaft bushing for the torque converter to work. If I ever get some free time, I will get back to work on bolting a well known 3 speed automatic to the nailhead, and still use the torque tube.
