Back in 'olden times' it was fairly common to find a conversion bellhousing and swap in later model V8 engines, from several different makes, into early Ford cars and trucks. My question is, how reliable is the rest of the drivetrain, namely the transmission, and the LD 3 speed in particular, to hold up to the additional HP and torque of a more modern V8 over the flathead? (the stock Dana rear with it's low gears would be traded for a more highway friendly 9") I'm thinking a stock 302, but even that would have double the power of a flattie. As cool as a flatmotor is, adding creature comforts like AC and PS are a lot easier with a 302, but I think it would be a lot of fun to keep the 3 on the tree, if possible. I'm not talking hot rodding or racing or burnout contests, just normal to maybe lightly spirited driving.

Sure, one could probably go to the trouble to figure out how to attach the linkage to a later 60's 3 speed that would have come with a 302, but if one is going to do that kind of figuring and fabbing, they might as well go all the way and fit a 5 speed. But it would also be a shame to do all the work to swap in the 302 only to find out the stock 3 speed will grenade the first time you let out the clutch. I seem to recall something about putting Lincoln Zephyr gears into the Ford trans case for longevity, but I don't know any of those details.

Thoughts, gentlemen?

 

Zephyr gears were used for their gear ratios, not strength.

People used to put nailhead Buicks in front of the LD 3-sp's, and they seemed to last a reasonable amount of time unless thrashed. I don't think I'd be too concerned about a 302. Trans capacity is based on torque and RPM. The flatty having big torque down low is likely as hard on the gears as the torque at higher RPM of the 302.

 

I do know that you can wipe out a light duty 3 speed by dumping the clutch to kill a flathead V8 when it wouldn't shut off. Don't ask me how I know that.

 

With a 30-lb flywheel, I don't doubt it!

 

I finished my truck in 2003, started drag racing in 2005. I have a 239 y block bored and stroked to 283”. I used to go through the water box and do burnouts, but I always left off idle at 1000 rpm’s. I have the light duty 3spd on the column and Dana 44 4.27 rear. I drive around the water box now and find I can win without doing all that stuff. Still leave off idle, racing 17 years now without breaking anything. With the open rear, I figure I’m going to spin one tire before I break anything.

 

https://www.holley.com/products/driv...gs/parts/15200

I thought I had seen a less expensive "6 bolt SBF to old square pattern transmission" patterned bell on Modern Driveline.

The problem is Ford changed to 6 bolts at the same time they changed from the "square" pattern to the "butterfly" wide pattern. Some transmissions from the mid '60s have both patterns. Since both patterns are present it would seem like they were covering the old 5 bolt/narrow and the new 6 bolt/wide--in other words, they didn't make the new bell in the narrow, but the made the transmissions to fit either.

A wide pattern aluminum bell would be a risky proposition to redrill for the narrow pattern. Not impossible but risky.

 

You were drag racing a 283" yblock? Whats it run for et?

 

My best is 16.88 @ 81 mph.

 

Only a couple seconds off a Boss 429.....

 

I like getting a head start. I’ve had my share of red light wins.