Thread: 1965 Biscayne/5 speed conversion

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They are only a "weak link" when you exceed their intended use. AKA Torque rating! They are not a Top Loader or Super T-10, but if you can work within the confines of the ratings. They are ok.

Yepper.Your right. The T5's in the Astro's which was the same one behind the 305's was rated at only 170 foot pounds.

Here is a thread about the T5's and beefing them up.

AstroSafariVans.com • View topic - Ultimate Astro 5 speed manual transmission build

So like the millions of 305 chevy's and millions of 302/5.0 ford's, the T5 is a fine transmission. If your going to be doing burnouts and drag racing, you'll shorten it's life. Otherwise, it'll go tens of thousands of miles with no issue!

Double posting.

When I was looking into a T5 for my project the one thing I did do aside from the links I have provided was to talk to Toni the owner of A & M Automotive.It's a tranny shop that he has operated for well over 40 yrs. In order to prove his point he took me in the back of the shop and showed me a 55 gallon drum filled with parts he took out of T5's because they are a poor design.I have known Toni for gezz it got to be 20 yrs and I asked him about if I just drove it normally,he told me most of those parts in the drum where from drivers who he didn't think where out beating on their cars.Added that those trannies just don't hold up. It's the T5's that are a bolt in on pre 1990 Astro's with the correct shifter location given the power train offset to the passenger side.So because I am a stick shift guy I am kind of stuck not having a T5 work for me without spending a boat load of money and still not be sure it would last even if I built a World Class T5 as the link I left about the T5 upgrade.

So still not persuaded I did more research. I am a member of a major Camaro forum.There guys talk about the failure rate of the T5's with 305's and how it isn't under consideration when doing any 350 swap. The low torque rating being the major factor of only 175lbs(I corrected myself when I posted it being 170 lbs) That anyone doing any kind of 350 has to upgrade to a T56. And even those need parts upgrades as I posted which makes them very expensive.

So as it stands now I have concluded Don I have no cheap answer for a O/D stick shift. Kind of gave up throwing my hands up in the air.

With your current trans,maybe it is just you going back and readjusting the shifter and throw-out bearing. You didn't say if your trans was the one used while the car was being drag raced.Maybe it needs to be rebuilt which seems to me would be cheaper than a conversion to a O/D. With a O/D and those rear end gears you would have to change them too. The cruise RPM's I would think would be way too low.

What would you guess is the HP/TQ ratings of your 350??.

Thanks for all the info......my 350 is around 300 hp & I will be getting into it from time to time thus, it
looks like I shoild not consider the T5.

I will continue looking but might have to learn to love my M-20.

Don

Don there is another overdrive option although it is a 4 speed not a 5 speed and as such the gear splits are not optimal.

That is the Chevrolet version of the New Process A833 overdrive transmission (based on the NP A833 that Chrysler used for years behind all their big and Small block engines).

I have the Chrysler version in my 57 Plymouth with the 354 Hemi and 4.10 gears (the OD ratio makes the final ratio equivalent to a 3.00 ratio). I’m running 235/70/15 tires. The car probably weighs about the same or maybe just a bit more than your 65.

FWIW here are my impressions of the transmission.

It’s has given me a very good service life so far and yeah, I “shown off” a bit with the car (with a HEMI, Tri Power and 4 Speed who can really resist).

The transmission comes with a 3.09 low gear and with the 4.10s low is really about useless when you jump on it. That being said, I have a pretty healthy cam in the car and for normal driving around town it really make the car well street mannered leaving stop signs and such. If I were to do it again I would probably step down to something in the 3.75 ratio area in the rear end. There is a pretty good jump in ratios between 2nd and 3rd (which is the 1:1 Ratio), but with the rear end gears and torque the Hemi makes it’s not all that noticeable. The OD ratio on the transmission is .73. Overall with the gear ratios I do enjoy driving it on the street but if I were to ever get serious about drag racing the Plymouth I would go to a conventional non OD transmission for the better ratio splits.

I’m using the Inland (Chrysler factory) shifter on mine and it shifts really nice. It has defiantly got a old school feel to it with the long throws but you’re going to run into that anytime you have the long shifter handles necessary with the 50-60s cars. The throws could be shortened by re-drilling shift arms, but it’s something I haven’t bothered with.

I got lucky with my overall combination, at 75 MPH the car is running at 2600 RPM, and the engine is in a happy place and gets 20 MPG (with the AC on).

These transmissions were used in some 70s-80 Chevrolet trucks and are not very well know or sought after so it usually take a bit of looking to find one. The plus side is they usually don’t command a high price.

Here’s a link to one that was put in a 65 Impala.

The New Process A-833 an Alternative to a Muncie Borg Warner


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HMmmm.. and my buddy's 91 5.0 mustang with over 100K miles must be a freak... If I could locate a World Class T-5 to put behind a small block, I wouldn't hesitate for a second!