Manual to Automatic Conversion
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From: Jackassville
Manual to Automatic Conversion
yo after thinking and delibrating a lot ive deicided to convert my 66 4 speed manaual to a C4 or C6 auto. i dont know anything about them are they three speeds or 4 speeds? also which one of the two would be better for accerlation and towing? i have thought through all the details and it seems like this is what i need to do for the conversion. new radiator with auto tranny fittings, eletric fan, some sort of adapeter for the bellhousing? auto linkage and fittings anything else im missing? can you buy kits that come with everthing to do it?
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From: North Carolina
The C4 and C6 are both three speed trannies with the same gear ratios. The C4 was used in small block applications whereas the C6 was meant for big block applications. While the C6 is the stronger tranny, the C4 can be made to be very strong, though not as strong as a C6. The C6 sucks more horsepower than the C4 which will no doubt affect acceleration, so to answer your second question: It depends on what you are towing. All other things being equal, I'd go for the C6. Since you are going from a manual to an automatic, the work involved will be the same either way. C4s and C6s are common so availability is not an issue. Your list for the conversion sounds pretty good but you'll also have to figure in a new (or just shortened) driveshaft which is not much. For kits, I'd try Advance Adapter. If they don't offer a kit, they may be able to direct you to someone who does.
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From: North Carolina
Yeah, I think you might be disappointed with the loss of that granny gear that the 4 speed has which is 6.39 or 6.69 (T98 vs NP435). In comparison the C4's/C6's 1st gear is 2.46. The C4 (and C6's) other gears are 1.46 and 1.00. Is there something else that worries you about the 3 speed other than that?
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From: Jackassville
well i will miss the granny but does it have plenty of punch in first despite the gear ratio? does the 3 speed cruise at nice RPM at highway speeds? also how much power can i expect to lose my switching to an automatic? i was thinking of going with aftermarket torque conveter which might help with accerlation also. i found a nice c4 in jegs for a thousand bucks but im worried about the three speed because of the loss of a low gear, but heck with my futre mods i should have plenty of torqe to tear up the tires even with the auto. is there any problems or bugs specific to the C4? will it hold up to heavy use as long as i mantain it properly?
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From: Jackassville
one more thing, what is the towing capacity if the C4 ive tried to find out but cant find it anywhere and i dont want to tear it up from hauling my tralier.
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From: Joliet, Illinois
Just go with a C6 (a whole bunch stronger and not all that less HP loss) and there is no adapter needed as it's a stock option, ford trans to a ford engine.
And if it's an Over Drive you want, just add a Gear Vendor OD unit to it and you get 6 forward gears and 2 reverse!
As far as highway speed, it's got a 1:1 top gear ratio, just like most all 4 speed manual transmissions are 1:1 in high gear as well, so the rpm's will be similar and the torque converter (actually multiplies torque when starting from a stand still) will make up for not having a granny low (climbing vertical walls excluded).
And if it's an Over Drive you want, just add a Gear Vendor OD unit to it and you get 6 forward gears and 2 reverse!
As far as highway speed, it's got a 1:1 top gear ratio, just like most all 4 speed manual transmissions are 1:1 in high gear as well, so the rpm's will be similar and the torque converter (actually multiplies torque when starting from a stand still) will make up for not having a granny low (climbing vertical walls excluded).
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