First Flathead build- need guideness

[Midnightcaper]

I say build what u want. Sure u can go with a boring stocker and it will be a lot cheaper. But that's not any fun. It's your wallet no one can tell u how far to open it.

[flatheadmurre]

If you wan´t over 150hp and reliability/drivability go blower !!
Flatheads really like blowers and you don´t need to bore and port it hard to get the power you wan´t.
Next is if you wan´t traditional style or not...
Don´t stare at the hp figures only a 150hp engine will make that light car move as fast as you dare to drive it
Looking forward to a nice build thread

[deuce_roadster]

If it were me, I would rely on people (like Ol Ron) who have built say a minimum of 100 flathead engines more then on articles I have read. There are so many issues not covered in most written magazine articles. One of the many problems with these engines is that the deck in not real thick so decking the block just for the hell of it is not a good idea if it doesn't need to be done. You can't get 50+ years of experience from a tech article.
Do you have a NOS block or French block to start with? If not, search this forum for what is considered necessary testing of a used block. Most people go through many blocks before finding one even usable. Anything can be done if you have enough money so maybe you have no real restraints. I just hope you don't spend a bunch of money and end up disappointed. Good luck on your project, my first car which I stated to build when I was 12 was a Model A with a 39 trans and model A rear end. I "financed" this project mowing lawns.

[Ol' Ron]

There are many T-5 transmissions out ther that are much better than the S-10, I'm using one from an 87 mustang, some use the camarro box. These are much stronger and have better ratios.

[Flathead-Arm]

Originally Posted by Ol' Ron

There are many T-5 transmissions out ther that are much better than the S-10, I'm using one from an 87 mustang, some use the camarro box. These are much stronger and have better ratios.

You are correct,
I think those are called Word Class T-5. Those are much stronger. But I figured if I'm only 250hp, the WCT-5 would be overkill. Plus I think I would have to change the rear tail section from that of an S-10 anyway.
I was quoted $150 from a junk yard with 15 S10's sitting on the lot. So at that price, why not go for it? If it blows up, I can then get a WCT-5 then use the tail section from the blown tranny. Makes sense???

How about the displacement? Would I be better off going with a 3-5/16 rather than the 3-3/8? Will it make that much of a difference?

Thanks for your input.

[JSeery]

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A T5 is a good transmission behind a flathead, the problem can be the S10 versions have truck gears in them, not high performance gearing. I like the T5z (Ford motorsport version) with close rato gearing paired with a 4:11 rear end.

You can modify the gearing in a Chevy bolt pattern T5 (S10) or work with the Ford pattern case.

[V8COOPMAN]

Originally Posted by Ol' Ron

There are many T-5 transmissions out ther that are much better than the S-10, I'm using one from an 87 mustang, some use the camarro box. These are much stronger and have better ratios.

Ol' Ron speaks with much wisdom. The ONLY reason to think "S-10" when talking T5 transmissions is this S-10 TAILSHAFT HOUSING (shown below), which will bolt-on to ANY T5 transmission. It's only purpose is to move the shifter farther forward, which obviously helps guys get the shifter closer to the old Ford shifter location. The S-10 transmissions themselves have awful gear ratios for anything but a wimpy, underpowered powerplant. 1st gear is usually not even usefull. DD



Comparative picture showing shifter locations:

[Flathead-Arm]

Actually the WCT-5 were only in the Mustang GTs. If I look at a mid 80's Mustang and a mid 80's S-10, they are both the NWC and the gear ratio are similar....

[Flathead-Arm]

I imagine the selector shaft would also need to by swapped over.

[V8COOPMAN]

Originally Posted by Flathead-Arm

You are correct,
I think those are called Word Class T-5. Those are much stronger.

"WORLD CLASS (WC)" has nothing to do with STRENGTH. The biggest differences between NON-WORLD CLASS (NWC) and WC transmissions is the different materials used in making the blocker rings (synchros), the difference in types of bearings used between the two, and the means of lubricating the surfaces that 1st, 2nd and 3rd gears ride on, on the main shaft. You will note that the biggest difference in TORQUE ratings is between transmissions with "LOW" 1st gear ratios....and those with "HIGH" 1st gear ratios. That 1st gear torque multiplication (4.03 in an S-10 trans) vs 2.95 in a Camaro, places tremendous forces on the case with the HIGHER-NUMBERED (4.03) ratio. DD

[Flathead-Arm]

So you're saying I should be looking for an 83-84 Mustang, that has the 2.95 1st gear?

[Tim Ayers]

This is turning into a good lesson on T-5's. I didn't know that about Non-WC v. WC. I also didn't realize the S-10 tail shaft bolts on to the other "mid-section" of these boxes.

[V8COOPMAN]

Originally Posted by Flathead-Arm

So you're saying I should be looking for an 83-84 Mustang, that has the 2.95 1st gear?

I'm looking at your tentative package. It gives me a good idea what you're working with. Don't take this wrong, but actually realizing even 200 hp in a flatty does not come easy, nor anything near inexpensively...just sayin'!

You're building an 8BA....not a thing wrong with that. With that in mind, I would suggest that you look for an '83-'87 Camaro NWC T5. They have the 2.95 1st gear gearset. The case will have the familiar Chevy bolt pattern and the input shaft will be 26-spline. I suggest the Camaro for a couple of different reasons, one of which is the ease in adapting it to a flathead. Below is a picture of a Camaro-based T5 that we just adapted to an 8BA in a '35 pick-up. In fact, we modified the rear of the T5 so that we could adapt it to an original Ford torque tube rear end. Click the link below for our complete thread on that build, which includes MUCH basic T5 info. Anyway, note the WILCAP adapter, which is bolted between the 8BA half-bell, and the Camaro T5.

http://www.fordbarn.com/forum/showth...t5+torque+tube



Your plan above indicates that you want to run a 3.73 or 4.11 rear ratio. Nothing wrong with that either, but ALL the more reason NOT to run an S-10 gearset with a 3.76 or 4.03 1st gear. IF you were to run a 4.11 rear in combination with a 3.76 S-10 1st gear, that works-out to an overall 1st gear ratio of 15.45 to 1. Think about it.....that's worse than the granny 1st gear in an old backwoods lumber truck. And if you get the S-10 with the 4.03 1st gear ratio, that's even worse with an overall 1st gear ratio of 16.56 to 1. Multiply 1st gear times the rear end ratio. Just to give you a realistic idea of why these combinations are awful, most old Fords had a 2.82 1st gear ratio (the Camaro V8 T5 is really close at 2.95 1st gear). Most of those old Fords came with 3.78 rear ratios. That combination works out to a 10.65 to 1 overall 1st gear ratio. I've always felt comfortable aiming for a ratio between 8.5 and 10.5. In fact, these two numbers are very close to what most standard shift automobiles with torquey engines seem to come with from the factory. One more thing to figure into all of this is rear tire diameter, but if you get the gearbox and rear end gearing way off to start with, you're going to be VERY disappointed in the result of an otherwise really-cool-shifting old hot rod. I hope this helps a little. I'll try to answer any questions you might have. The Camaro NWC boxes are still out there at swap meets and on Craigslist. Then, you'll need the S-10 tail housing, along with the correspondingly short shift rod. This stuff bolts right up. DD

[V8COOPMAN]

Originally Posted by Tim Ayers

This is turning into a good lesson on T-5's. I didn't know that about Non-WC v. WC. I also didn't realize the S-10 tail shaft bolts on to the other "mid-section" of these boxes.

For you guys that have an interest in really getting to know MORE about the T5, this guy's link below hits the basics fairly well......some very good reading here! DD

http://lugnutz65chevystepside.weebly...info-page.html

[Midnightcaper]

Moderndriveline makes a tail shaft that will bolt onto a mustang t5 and comes with both mechanical and electronic speedo options.

[19Fordy]

Holy Mackerel V8!

That website is awesome. Thanks.

[Ol' Ron]

I like to build spending the least amount of money. Using a late chevy or Ford T-5. You can bolt that to a flathead for less than 200 bucks. Using a Spicer/dana rear you get post.disk brakes, 3.73 gears for 150-250 bucks. Now if Trump can raise my SS I might go to a blower.

[Flathead-Arm]

Originally Posted by V8COOPMAN

For you guys that have an interest in really getting to know MORE about the T5, this guy's link below hits the basics fairly well......some very good reading here! DD

http://lugnutz65chevystepside.weebly...info-page.html

Half way down the page... What gear ratio is best for me?
Has all the info we've been talking about.

[Flathead-Arm]

However, contrary to my belief I thought the high rear end gear would provide quicker RPMs. But its the opposites. I should be trying to decide between 3.73 or 3.42.

[Flathead-Arm]

This looks good....