I own a 81 F100 with a 4.9L 6cyc 3 speed auto, If I was to put a 360 V8 in it would the rear end, drive shaft & transmission be ok or would then need to be upgraded?

 

Not sure if the bell housing bolt pattern will be the same, the transmission and drive line will be fine. Don’t know what rear gear ratio you have but you will probably want to be 3.08-3.50 ratio unless you plan to tow heavy loads or drag race
I have a 3:50 in my 302 3spd, haven’t driven it much yet, but first test drive seems like it may be geared a little low

 

Thank you that is great info

 

If you can get me one new rebuilt for $2500.00 CDN same as the 360 I'm all in

 

An advantage using Small Block Ford 302 or 351 is the block has the same bell housing bolt pattern your 4.9L six and the V-8 will bolt right up.

Note, you CANNOT use the 4.9 flywheel, it has to a flywheel for the V-8. The 6 and V-8 engines are balanced differently, one internally and other externally so no mix matching.

A search here on FTZ or online and you should fine any or more info.

Cap

 

Wow that's super info so now I know I'm looking at a lot more money in other changes and labour cost. It is starting to make more sense now staying with the small blocks Thank you

 

Just did a quick google search for Ford small blocks for sale and several vendors popped up with remand long blocks for less than 2k. You would have to purchase add on parts, intake, carb, water pump, distributor, fly wheel, harmonic ballencer
With some good shopping I think you could make your 2500.budget
Don’t forget pre 1985 302 engines use a 28oz ballencer and flywheel, post 85. are 50 oz
Don’t know where your at but I have a 2 brl intake and carb for a 302 that your welcome to

 

Again thanks for the great feed back. I live in Ontario Canada and I'm not mechanically knowledgeable and will be paying someone else to do the work. Hoping I can find some one who's project had to be cancelled and he has a new rebuilt lying around that he is selling for a reasonable price. Came across three 289's but they ranged from $4500 to $6500. I was hoping to be able to doing every thing for $5000 or less.

 

After rereading your initial post and the fact that you truck has a automatic transmission. I have no doubt about bolt up BUT, I don't know how my advise about internal and external balancing plays out as far as Flex Plates and Torque Converters go.

Is there a different Flex Plate and Converter for the 6 and V-8. I don't know about that, sorry, maybe some one else with the knowledge can enlighten us both about that.

Cap

 

My 76 302 and C6 has a 28 oz harmonic balancer, and a 28oz weight on the flex plate. There is no weights on the torque converter. The 5.0 after 85 uses 50 oz weights

 

If you are still thinking 360, I will point out that they stopped making them in '76, it was never factory installed in your chassis. I don't know what engine perches will work, and an oil pan may cause problems, both changed considerably in 1980. Also, FEs have a different bell housing pattern than anything newer.