I know this isnt probablly the right place to put this but i figured since it was going in a '55 f100 it was a place to start. ok here goes... im doing a "hotrod resto" on a '55... The engine is a 408 cleveland stroker... the truck had a 302 with a c4 tranny in when i purchased but i know the stock spec c4 wont take the abuse of the new motor. So i was considering an upgrade to a C6 was was told it was pretty parasitic on the power... i know i should have put this earlier but at this point i know some of you are going off on the screw the auto put a stick in it tangent but out of personal preference and me being lazy i would rather go auto and just be done with it, i know im talking about the power loss of the c6 and all that but im dead set on an auto... ok back to it.. C6 power parasite.. so then i was considering a built C4 less power loss and can be built up enough to handle the power. But now the thought of it being a cruising machine and less of a race car has thrown the overdrive tranny into the mix. The 4th gear would keep the the motor spinning a bit less when just strolling on the highway ( i live 45 minutes from any major city so the ride into town or even the track with the motor spinning at 3500-4500 rpms on the highway is insane) plus that extra gear would get the gas milage down just a hair... its gonna drink it fast enough sitting still. So here is the question what should i bolt up to this sucker to give it a balance of driveability yet the ability to lay the power down on demand... btw fuel economy is truely an afterthought and i just threw that in there. Im not really concerned about branding more so just what model of tranny... pros and cons and what nots... c4? c6? aod? aode? eieio? etc? thanks for any help guys!

 

The C6 will rob a little power, but unless you are competitively drag racing it on a regular basis, you'll never know the difference. Bozo bench-racing gave the C6 a bad rap. It's a great street/strip tranny and has proven tried and true behind some pretty violent big blocks in stock/mild form. If you are seeking competition use, then yeah, shell out the $1500+ for a well built C4.

Onto your other thoughts... Yes overdrives are nice and certainly the way to go these days. The AOD would be choice, but you'll need to spend a few extra $$ to catch some upgrades to it so it'll survive behind the Cleveland. The AODE is a little more stout than the AOD but requires a standalone controller to operate the electronics. The E4OD is a much stronger unit yet, but like the AODE will require a stand-alone controller to operate it as well... These controllers are usually at the tune of $500 give or take.

Just my thoughts.

 

Long discussion of the AOD here:

https://www.ford-trucks.com/forums/1...ade-parts.html

It gets expensive real fast to beef one up.

Note '88-'93 models have improvements, early boxes are trouble.

 

I Don't think your considering a manual but here are some numbers:
T5z tranny to a Ford 408 stroker, Diff. gear-3.07, tranny 5th gear-.73, tire dia. - 26.25", @ 75mph turning 2,151 rpm's.

___________________________________
48 Ford F1 - Darkside
46 Ford Tudor - Street Rod

"Happiness - 3 pedals and a 5 speed"

 

First you need to decide what the purpose of the truck is supposed to be: a street vehicle, a race vehicle, a dual purpose vehicle. A dual purpose vehicle is always going to need to be a major compromise, it's never going to be good for both, so you then need to decide what you are willing to give up from one use to improve the other. The weight distribution of a pickup already handicaps it as a strip warrior without major chassis work that will make it less suitable for street driving. A dual use vehicle is most likely to be a bracket racer unless you are street racing. The loss of a handful of HP is really meaningless in bracket racing where consistency is more important than a couple tenths et. I won't even discuss street racing. An all out racing transmission with it's matching high stall speed converter is going to be an uncomfortable driver and hard on parts. A ratio that provides low highway rpm/high speed, good mileage is not going to launch very well and/or is going to be spitting parts regularly.
My recommendation would be a beefed up c-6 since it's likely you are going to be overloading the drive train regularly and the 6 will better handle the abuse.
As one who has tried the combo use my real suggestion is to build a dedicated drag car out of something more suitable, put it on a trailer and tow it to the strip with the F100. In the long run it would be cheaper and more satisfying.

 

Yeah what Ax said.. (well put Ax)

Take for example... I have 2 later 70's fullsize trucks both runnig 460s and C6s and my '56 F100 is runnin a 390 and C6. The '56 on it's last trip got a best of 14mpg on the freeway with an average of about 12mpg. Now that's with the RPM in the 2500-3000 range on the freeway. Not bad at all for spinning a long-arm motor that hard for a distance. Not sure what my rear gear is, but I'm betting that if i put a taller set (numerically smaller) in it I'll be able to pick up several MPGs and with the light weight of the truck and nice power and torque of the engine i doubt I'll even notice any power loss.

Now my 460 trucks get about 10-12mpg... on the freeway, loaded, unloaded, doesn't seem to matter. I have 3:00 gears in one an 3.25:1 gears in the other. With the torque and power of either truck i can easily drop to 2.70s and still have plenty of pulling power. Expecting to gain some MPGs there too. I looked into overdrives but with 460s I'm stuck using E4ODs with the added cost of a standalone controller (nothing else available for a 429/460). Essentially a $1500-$2000 cost just to run an overdrive. Don't even think I spend that much in fuel now in a given year....