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View Full Version : 5spd bellhousing strength?



choltz
09-01-2009, 11:05 PM
Hey,

I'm swapping the engine & 5spd out of my '89 into my '69 Mach 1. Not here to argue the value, suffice to say I like the 20 MPG I get with the bird better than the 8 MPG with the 351W in the Stang, not to mention I'm tired of messing with the carburator!

Anyway, as part of the swap, I'm having to build a front sump oil pan and I'm wondering about the fact that the 5spd bellhousing bolts to the stock oil pan. Does anyone know if the integral bellhousing is just weak, thereby requiring the added rigidity from the oil pan? I've found that the bold pattern for the tranny perfectly matches the standard smallblock pattern (my '69 4spd looks like it would bolt right up, including the input shaft length), expect for the fact that the 3.8 uses 6 smaller bolts (including the 2 in the oil pan) rather than the 4 larger bolts on a smallblock.

My concern is whether to risk running with just 4 bolts or if I should build brackets onto my fabbed steel pan to carry the extra 2 bolts. Of course, doing so is going to cause some additional problems for the power steering slave cylinder.

Any thoughts, or does anyone have any ideas on digging up additional info?

Thanks a bunch!
Corbin

Hock
09-01-2009, 11:55 PM
The bell housing does have a decent thickness in my opinion, though the additional bracing that Ford did with the oil pan may have to do with the fact of the length and weight of that trans.

But its really hard to tell. I would say just incorporate that into the new oil pan that you are gonna make.

Good luck!

91 XR7
09-02-2009, 05:23 PM
Well i've, and a few others after me, have been running the SC (M5R2) tranny behind SBF (302 and 351W) without those bolts for some time (i think i'm closing in at like 8 years now, last two not driven thou :( ) And i've never been THAT easy on the car ('91 XR7) mind you it IS a slow 5.0L (which seemed so much faster then my '91 SC)

Flip
09-02-2009, 06:40 PM
Hey,

I'm swapping the engine & 5spd out of my '89 into my '69 Mach 1. Not here to argue the value, suffice to say I like the 20 MPG I get with the bird better than the 8 MPG with the 351W in the Stang, not to mention I'm tired of messing with the carburator!

Good luck with the swap but I don't understand how your Carb 351W gets 8 MPG and what problem you could have with a Carburetor that would drive you to a SC 3.8 swap.

Again good luck with it.

SuperChicken89
09-02-2009, 09:31 PM
Hey,
My concern is whether to risk running with just 4 bolts or if I should build brackets onto my fabbed steel pan to carry the extra 2 bolts. Of course, doing so is going to cause some additional problems for the power steering slave cylinder.

Any thoughts, or does anyone have any ideas on digging up additional info?

Thanks a bunch!
Corbin

Corbin

You won't need the additional support. I swapped an SC AOD into my 69 Cougar without those bolts with no problems what so ever. The 69 Mach I and the 69 Cougar are the same driveline/chassis from the B pillar forward.

I'm curious why you are only getting 8 mpg with the 351W setup. I get right at 20mpg highway with the AOD and 14mpg city from my 351W if I keep my foot out of it and thats with 355 rear gears. Since I rebuilt the carb last winter, the car hasn't run better in 10 years. I'm not going to try and talk you out of your engine/trans swap but a carb and distributor ignition system is a whole lot simpler than the SC's EEC system.


The bell housing does have a decent thickness in my opinion, though the additional bracing that Ford did with the oil pan may have to do with the fact of the length and weight of that trans.


I know the AOD required longer bolts than the FMX trans that came out of my Cougar. The mounting area of the AOD bellhousing is thicker than the original FMX trans. I would imagine the SC Mazda 5-speed is the same way. I can also tell you the AOD weighed a little less than the cast iron FMX trans. I would imagine again the SC 5-speed would be about the same.

Bryan

sinhumane
09-03-2009, 08:43 PM
i always thought about this swap into a first generation mustang. cant wait to see how it turns out.

91 XR7
09-03-2009, 09:53 PM
there's someone local to me, whom i never seen in person, that has a SC engine in a '66? Falcon.. There's also another person with an SC engine in a Early '80s Mustangs (Fox chassis)..

MustangJake88
09-04-2009, 12:14 AM
there's someone local to me, whom i never seen in person, that has a SC engine in a '66? Falcon.. There's also another person with an SC engine in a Early '80s Mustangs (Fox chassis)..My uncle (lilredstang as known on these forums) has a Super Coupe motor in his '90 notchback Mustang. That thing is an absolute ROCKET! MPX blower, 60lb injectors, TB, MAF, all kinds of stuff. It's crazy.