Okay, I was planning on using my T-5 for the blown stroker motor for my 37 coupe. Problem is the T-5 is only good for about 300 HP and I know this motor will put out more than this. A local company showed up at a car show over the weekend called Modern Driveline (MDL) http://www.moderndriveline.com/ they make a super duty T-5 good to 450 HP and also TKO 5 and 6 speed units. They make an adapter plate for the Y Blocks and also a steel bellhousing. Instead of sending off my T-5 to "G-Force Transmission for a rebuild with their gears and main shaft, I thought I'd be better off  with a Super Duty T-5 from MDL and one of their adapter plates to use on my Cast bellhousing. However, MDL is recommending that I go with a steel bellhousing due to the "rotational Force" being put out with the kind of HP I will be making. I had not considered this issue before and aside from the high cost of the bell housing I'm afraid there will be differences in the dimensions between the cast and steel bellhousings that will cause issues with my rear tranny cross member and drive shaft length. So, do you think I need to go with a steel bellhousing for this set-up?

  Ron Lane,  Meridian, ID

Probably not needed.  Lot's of powerful Y-blocks at the nationals with no fancy bellhousings and of all the failures there have been, a bellhousing is not one I know about.

The Y is from a time when things were still pretty over built.  The bellhousings are iron and pretty stout.  My '88 Firebird on the other hand has an aluminum bellhousing that seems paper thin by comparison.  So were it for my Firebird, I'd be concerned but for a Y, not really.

The bellhousing they sell is a Quick Time.  There have been issues with those, one of those products where they seem to have just got dimensions to manufacture it but didn't actually try it.  I'm pretty sure there is a topic about it and I don't recall exactly what the issues are.

The only reason you should need the quick time bellhousing is if you will be racing at a level where a blow-proof bellhousing is required.  In a similar regard, if you plan to abuse it often, it might be a good idea for that extra insurance, so that you can keep your legs.
I wouldn't expect this to cause much of a problem with your crossmember as the input shaft dictates a certain dimension between the crank and transmission flange, regardless of the bellhousing used.  If it is different, it will be by a small, easily correctable amount.

The Super Duty T5 they sell appears to be the standard aftermarket T-5z, that tends to be rated anywhere from 300-330 ftlbs.  If they offer a 450ftlbs T5, then it probably is a G-Force or Astro upgrade.  Check with them all.





Lawrenceville, GA

Not sure how things will fit together in your 37 but I'm 99% sure the steel Quick Time bell housing will not accept the standard y- block starter.  That unique sound of the starter is something I would hate to give up if I didn't have to. Good luck with your build and keep reporting,  JEFF...............


64F100 57FAIRLANE500

Thanks guys. I think I'll keep my cast iron bellhousing. The owner of this company (MDL) said he used to work for G Force Transmissions and that they didn't hold up to their supposed HP rating. The Super Duty T-5 that MDL sells has all new gears, syncro's and main shaft. I'll talk to them more and compare my parts to theirs, but I'm not really interested in re-inventing the wheel with a new, $700 steel bell housing.

  Ron Lane,  Meridian, ID

They might use Astro, then.  There can't be too many places that make T5 upgrade parts.  I think Astro produce their own beefed up case.  There is some place that does or did at one time.  Astro's case does look different than the factory case of the T5 in my truck.


Lawrenceville, GA

Where steel bellhousings benefit is when the flywheel comes apart at 9k

I agree with the above comments about the strength of the bell housing.  I looked into the Quick Time bell housings a few years ago and found that in order to use them on a Y Block you must also buy their redrilled FE flywheel and starter to work.  The Y Block parts will not fit.  Also to note, the TKO 5 & 6 transmissions are higher from the center line of the main shaft than the T5 and may hit the tunnel of your car.  Just saying.

If I ever change to manual transmission, it gonna be zf gs6-53dz from BMW.
Six speed and stands a lot of abusing.


Hyvinkää, FI

I know this site doesn't speak to kindly of using of using GM stuff but what's the problem in using a Wilcap or Bendsten adapter to a GM trans and bolting up a GM bellhousing.  The starter would not be an issue as I read them but I'm sure there are other items to be addressed like the flywheel but I'm always open to any reasonable suggestion because I'm a hot rodder and that's we not only do but it's expected. Good Luck

56 Vic, B'Ville 200 MPH Club Member, So Cal.

A bellhousing adapter would be an unnecessary expense for this task.  Adapting a manual transmission is a fairly easy task, whereas adapting an automatic, which tends to have an integral bellhousing, is not.


Lawrenceville, GA