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I have a 70 Mach 1 351 Cleaveland v4 motor FMX Automatic Transmission,2nd gear does not work, I would love to put in a beefy Manual Transmission..what do I need? What would be the cost to but and install a manual zf5 speed? or to rebuild and beef up my FMX or C4? What are your thoughts on both.

Thanks
 

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Wow, an FMX behind a Cleveland. Is it a 2bbl or 4bbl? Well the FMX isn't a performance transmission. I would find a suitable C-6 for a smallblock and rebuild it with a large tranny cooler. On the manual side, you'll need these parts: Clutch/ brake pedals, clutch linkages, bell housing, clutch, pressure plate, flywheel, flywheel bolts, throwout bearing, oh and a manual trans with shift linkage if applicable. The Tremecs are nice however not as indestructable as they seem. After seeing my brother and nephew having to go through their 500's I wasn't that impressed. Of course they're pushing close to that in hp. It all boils down to how you want to drive it. Me...I'd go for the manual any day.
 

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There is very little available to increase the performance potential of the FMX. Get rid of it. It's a money pit. It would be easier and cheaper to install a beefed up C4 over a manual trans.

The C4 has strong aftermarket support and can be found built in several performance levels up to 1000 HP. Serious drag racers use this transmission. It's strong, light and simple. The FMX is an early, complicated and heavy design. Finding someone who can rebuild one correctly is another issue in itself.

Installing a nice street/strip performance C4 and torque converter will probably set you back about $1000-$1500. For a 5 speed manual, probably about double that or more. As for a part list for the manual trans, there's too much for me to list here, but conversion kits are on the market.
 

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Your best bet would be a C-6, that's what most MACH1's with automatic transmissions came through with back then. Be it a 351 Cleveland, or a 428 CJ they had C-6 tranny's in them very few had a C-4, Mike. SCT Tuner.:bigthumbsup
 

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I like the 4R70W I put behind my cleveland, it cost me around $1000.00 (300 for trans, 525 for computer and wiring harness, and I first shortened my driveshaft but ended up ordering one for about 200 or so))and I have been thrasing it for 2 1/2 years now. Its smooth when you dont stomp it and very agressive when you do. It has a .67 od and 2.84 1st, i run 389 gears and turn 2300 at 75 mph
 

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Well the FMX isn't a performance transmission. I would find a suitable C-6 for a smallblock and rebuild it with a large tranny cooler.
FMX is a pretty strong tranny, i have one behing my 351w with 420rwhp sure its been rebuilt. C4 would be better than C6 because C6 can cause lots of power loss to the rear wheels. C4 is also more common to beef up than FMX. But i do like my fmx
 

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The FMX has a strong gear train and for the most part are trouble free. It sounds like your second gear servo took a dump or a band broke. This sometimes happens if the bands are not kept in adjustment. The only weak point in the FMX is the case at the center support. C4s are easier to find in performance versions - my builds start at $750 - and are light, ridgid and strong.
Start with the cheapest fix first - pull the pan and check the band and servo - or have it checked. If it is cheaper than a new transmission then fix it. If you want to up-grade to a performance transmission consider the C4. They can be very streetable when you are easy on the throttle and monsters at the drags when you are driving agressively.
 

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Hay silver69 like to hear more about a 4R70W trans in a 351C 70 mach1 swap. Sounds like the most up to date way to go. No TV cable to mess with correct? What type CPU to use with the 4R70W? Any details greatly appreciated I'll doing one in March/April. Looking AOD, AODE and the 4R70W.
 

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Well let me begin then. It is an easy swap. The computer comes from Baumann engineering(becontrols.com) and the tranny can be gotten from any 99-02 v6 mustang or 5.0 econoline van. remember 5.0 van or 3.8 mustang. newer than 02 and the output shat of the trans has no worm gear to drive your speedo(yours will directly fit) if you remain carburated you will need a generic tps sensor form auto zone or somewhere and it is very easy to hook up, details at be controls.
the v6 tranny is very tough and I have been pumping 420 hp trhough mine for 3.5 years now(hard driving too)
when you get the trans you will need to cut off all the flat mounting plate looking things on the case- not needed for us and prevents trans from fitting. you will need to shorten your driveshaft to 49 inches center cup to center cup. get the driveshaft from the donor car or at a pull a part because you need the 4R70W yoke. if you do this pm me and I can give you the rest of the details.
the best part of this is the trans has 2 different personalities, a docile one that is so smooth you dont know its shifting except for the exhaust note and a strong, hard shifting trans for wot action(both at the same time). Next to fuel injection it will be the best money you ever spend on your car. its really a 5 speed because you have 4 gears and a lockup converter. your stock flexplate, engine plate and starter will bolt right on, uses dexron 5 fluid only. you change trans shift points and firmness on your laptop, its nothing short of amazing in my opinion
joe
 

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Sounds very interesting, I will post my 69 stang build soon. Checking out TCI tomorrow they mentioned a PCS Power Train Contol Solutions with a very simple non-PC trans controler. Some say 4R70W will not bolt to a Cleveland perhaps they just have not tried it?
 

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If you have a true Cleveland it has the same bell pattern as a 250, 289 (66-up), 302, and 351W. If you have a 351M it will have the same pattern as the 429 - 460.
 
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