MG Engine Swaps Forum

Came across a good deal on a rebuilt 3.1 gm engine and think I will get it and start getting pieces together for a conversion in the future.
I know several people have commented on the use of the v8 t-5 as a better choice than the v6 t-5...
My question is when I search for a t-5 I get dozens of hits from mustangs and couple from datsuns and few S-10. I do not get hits on GM t-5 (v6 or v8) , if it is a gm 5 speed from a V8 of a similar year, am I to assume its a t5?

If I have a 3.1 and a bellhousing that fits it for a 5-speed - will it take a v6 of a v8 transmission and would a ford t-5 bolt to it?

I would just like direction to search.

Thanks
-Kevin

Kevin,

First, try searching for a Camaro V8 T-5.

Second, the T-5 was the only 5-speed manual transmission used in the Camaro / Firebird.

Remember that RWD 3.1 engines have the starter on the right side and FWD 3.1 engines have the starter on the left side. Whatever bellhousing you use must accomodate the starter location on the engine you use.

Your question about using a Ford T-5 really opens a can of worms.

There are two very different transmission to bellhousing bolt patterns; the tall-narrow Ford pattern and the wide-flat Chevy / Muncie / Saginaw pattern. ALL Ford T-5’s (I-4, V6 & V8) used the Ford bolt pattern. All Chevy T-5’s (I-4, V6 & V8) used the wide-flat Chevy pattern from ’82 to ’92. From ’93 on, V8 Camaros used the T-56 and the V6 Camaro and I-4 S-10 used T-5’s with the tall-narrow Ford pattern. There were also some Astro vans with 4.3 V6 engines that used a Ford pattern T-5.

Input shafts are another issue. ALL Chevy T-5’s have an input shaft length of 7.18 inches. Ford V8 T-5 input shafts are also 7.18 inches, but Ford V6 T-5’s are 7.85 inches and Ford I-4 T-5’s are 7.41 inches. All Chevy T-5’s have a pilot bearing extension with a diameter of 0.590 inches. Ford I-4 T-5’s are also 0.590 inches, but Ford V6 and V8 T-5’s are 0.668 inches. The pilot bearing size is not really a big deal; both Jeg’s and Summit sell Chevy to Ford or Ford to Chevy pilot bearings.

All Ford T-5 input shafts are 1-1/16” diameter with 10 splines, but Chevy input shafts can be either 1” or 1-1/8” diameter with either 14 or 26 splines. You have to use a clutch disc with a hub that matches the input shaft diameter / spline count.

The input shaft bearing carrier extension (the thing the throwout bearing slides on) on a Chevy T-5 is 1.375 inches in diameter; on a Ford T-5, it is 1.430 inches. If you use a hydraulic throw-out bearing, it must match the housing. The input shaft housings may be interchangeable; I’m not sure.

Chevy T-5’s have two different shifter locations; on the front of the tailhousing (S-10) or the rear of the tailhousing (Camaro). All Ford T-5’s have the shifter on the rear of the tailhousing.

All Camaro T-5’s have a tilted “foot” for the transmission crossmember mount; S-10 T-5’s and all Ford T-5’s have a level foot.

Chevy V8 T-5’s have a 2.95 first gear while OEM Ford T-5’s have a 3.35 ratio. Most Chevy V6 T-5’s have a 3.76 first gear, but some are 4.03. All Chevy I-4 T-5’s have a 4.03 first gear. The only Ford T-5's with a 2.95 first gear were aftermarket units.

Since all Chevy bellhousings are designed for a 7.18 inch input shaft length, only a Ford V8 T-5 will work unless you change the input shaft. Obviously, you will need a Chevy bellhousing with the Ford bolt pattern. The ‘93+ Chevy I-4 S-10 bellhousing will bolt up to a Chevy V6 engine and has the Ford bolt pattern (the transmission mounts level). This bellhousing should work on a FWD V6 Chevy engine (left side starter). A bellhousing from the ’93 to ’95 Camaro V6 has the Ford bolt pattern, but mounts the transmission tilted 17 degrees to the left. You would need to turn the collar on the input shaft bearing carrier down from 4.83” to 4.68” to fit the centering hole in the Chevy bellhousing. A couple of the "conversion" companies that post here can also supply bellhousings.

The bottom line is that you can use a Ford V8 T-5 behind a Chevy 60 degree V6, but there are some definite issues. It would be a lot simpler and probably more cost effective to rebuild the appropriate Chevy T-5. The parts are readily available at a reasonable cost and a T-5 is not difficult to work on. You would have a good transmission and could choose the gear ratios you want.

I think I probably told you more than I know and more than you wanted to hear. I learned most of this the hard way and some of it may be wrong. If so, somebody let me know.



Edited 2 time(s). Last edit at 2009-10-06 11:56 AM by Barry Knight.

Great information Barry.
I would like to add that the early Ford T-5 trans can be mounted on the V6 Bell housing using and adapter and a pilot bearing form one of the speed shops outlets. The spacer is the correct thickness to compansate for the extra lenght of the Ford trans.

The idea behind on the spacer, was to be albe to use an early Ford trans due to the cost. The early Ford T-5's are nogt very inexpensive and can be found everywhere.
1982 to 89 I think 90 may also have the same bolt pattern and shaft input shaft length. After 85 they all were WC trans. Do not be concern if you get a good deal on a NWC T-5.

Bill,

It is not early / late that matters with the Ford T-5; it is V6 / V8. All Ford V8 T-5's, both early and late, had the same 7.18" input shaft length as GM T-5's. All Ford V6 T-5's used the longer 7.85" input shaft that can work with an adapter plate. FWIW, Ford is still using T-5's with the 7.85" input shaft on 3.8 V6 Mustangs.

It does look like there are some favorable gearing sets in the ford T5's which might be quite amenable for the V6 conversions. There's a great table of detailed applications and ratios
on http://www.allfordmustangs.com/Detailed/349.shtml.

Are the 93+ s10 bellhousing/clutch setups using the external hydraulic clutch actuation (similar to the earlier s10's)? If so, wouldn't that provide a way to avoid the internal htob's when using a ford T5?

Scot, With the D&D adapter, the newer V6 T5(3.38 first,.68 fifth)or 94-95 Mustang V8 with longer input shaft also sounds pretty good for the GM V6 with the Camaro rear. I still think the 2.95 first V8 Camaro T5 would be best for the stock rear gears.



Edited 2 time(s). Last edit at 2009-10-06 01:40 PM by 260mgb.

I did a quick look at all the tagged T5's described in the link I gave above. It does look like there are several good candidates with 2.95 first gears. It also looks like you can get quite a range of ratio of ratios, as well. The chart shows situations from fairly constant ratio of ratios to both sharply increasing and decreasing. For a motor like the GM V6 I'd guess the more linear the better. Comments?

WOW - very detailed. Thank you guys.
I am going to re read it a couple dozen times and start searching.
The engine I found is a completely rebuilt 3.1L with 5000 miles on it from an 89 pontiac firebird. bored 20 over, complete with computer and performance chips
Thanks

http://www.britishv8.org/Articles/Borg-Warner-T5-ID-Tags.htm

FWIW, there is one more option to add to this mess. A 1984 to 1986 Jeep Cherokee was available using the Chevy 2,8l, and the Ford T5. This would be an option to fit a Ford T5 with no machining or adapters.

.Ah, the joys of AMC... Anyhow, this is a source for a GM-to-Ford bellhousing, with external slave AND starter both on the passenger side.

Barry, I know you are correct, but, the trans you see in the picture came from a 1989 Mustang 5.0 from a friend who made a drag racer from his 89 Mustang, he gave them to me.
I also have a 1992 trans from a 5.0 Mustang with a 3:35 first gear, same length shaft and wider bolt pattern in the bottom.

I was going to install the 1992 trans in my project GT, but....I prefer the V6 T-5 with 3:76 first gear. the idea is that I can replicate the Camaro gearing in a lighter car.
Barry, can you verify what I have? I get confuse when it comes to Ford T-5 and their variations.

I am not arguing your information.

Duncan, it is great but......hard to find. Most jeeps were auto trans.

Bill,
I presume that you'll be using a non-3.9 rear with the 3.76 first gear transmission..?

Duncan,

Are you sure that the Jeep bellhousing is the same length as a GM bellhousing? I have one (casting # 8952000066) and it is 0.312" (aka 5/16" ) longer than all of the GM bellhousings that I have.

Barry



Edited 1 time(s). Last edit at 2009-10-07 04:04 PM by Barry Knight.

No Scot, I will be using a 3:07 with 23.5 tire dia, this will give the same gearing as the stock Camaro in a lighter car.
A 3:23 differential would be the same as installing a 3:42 in a Camaro. the difference is in the tire dia.
The purpose of my GT is a hwy driver cross country.

Bill
Thanks for clarifying. I suspected it was a taller ratio.