Hey guys,

I wasn't really sure where to post this - so I thought this might be the best place.

I have a 1974 F250 with a 300i6 with a t18 transmission. I've decided I want to swap the 300 out for a V8. I have never swapped an engine, and I am a beginner when it comes to engine work in general! What would be the easiest swap? What will fit the same transmission? What could I put it to make some good horsepower without breaking the bank? I will likely buy something I can rebuild and modify, mostly because I would like to learn. What does everyone suggest?

 

I'm not sure about the bellhousing but since the FE was primary the V8 option for your pickup that would be the obvious choice to put in it. you could also do a 385 series engine .

I'd do a 4v 390 if it were me, great engine good power and and correct for your year.

 

You could reuse your tranny with any engine these trucks came with, but you'll have to swap bellhousings depending on the application. Your 300 six bellhousing will mount to a SBF (302 or 351w).

Here's some info on the engine perches for the various engines.

Comparison Photos of Engine Perches - FORDification.com

 

I've heard the 390 is so bad on gas, some guys parked them. Are they truly this bad?

 

Wow, fantastic article. I'll be bookmarking this one, thanks!

 

None of the FE's were know for their economy. but none of the big blocks were.

A small block will be more economical if that's more important than power. though economical is a relative term when comparing these rigs to modern vehicles.

 

I'm running a 410 4V, 435, 410 rear and get 14mpg on the highway. The reason folks get bad mileage is when you have power/torque, how can you not want to feel that? I know I'm late, but I just watched Ford vs Ferrari...427 FE @ 7000rpm for 24 hours....WOW...
If your looking for mileage this is not it. I have had cars/trucks that on a good day got 5mpg. They made a Corvette with a 43 gallon tank. Smiles per mile!

 

Why do you want to do the swap? What kind of driving will the truck be doing the most of? I think these are the important questions to decide what kind of swap is best.

 

Since it looks like fuel economy is going to be a consideration I would go for a mid displacement V8 either a 351W or a 351C this will allow you to use your existing bell housing but may require sourcing engine perches. The 351W is also going to be the cheapest option (next to a 302) of all the possible engine choices. I would avoid the 351M, the only thing good about the 351M is it can be converted to a 400, they really have no saving graces anything they do can be done in the smaller, lighter and more reliable 351W .

 

Too bad. The 300 is a great engine with lots of potential. Add a 4V carb or multiple 2V carbs. And some EFI dual exhaust manifolds or some headers and they really wake up. And if you want more then raise the compression swap cams and port the head.

 

I do love the engine. However, it would be nice to make some good horsepower without blowing the bank.
That being said, I have looked at the Offenhauser intakes so I can go the 4V route. It's just a price road considering that there is not a whole lot of used performance parts for these units.

Also, would a 240i6 be worthy of this? I've got a 74 f250 with the 300i6, and a 67' f100 with the 240i6 (bored .030 over & rebuilt by P/O a number of years ago) which is the better candidate....

 

Engine swaps are not a cheap or easy solution. They always cost a lot more then you think they will and always take longer. You are looking at changing frame engine mount perches/towers, changing cooling system, fuel system, exhaust, wiring, etc. If you are swapping to a small block V8 ( 302, 351W or 351C ) you can use the same bellhousing and transmission. But you will need a different flywheel. The 300 is a neutral/0 imbalance where as the V8 will be either 28 oz. or 50 oz. depending on which engine and it's age.

The 240/300's can be built up on a budget. The intake and 4V carb would be the most expensive parts unless you got into the engine farther. How much it cost to build or upgrade one depends on how far you want to take it. And how much work and or fabrication you can do. Used performance parts are out there but it may take some patience to find good deals on them.

I prefer multiple carbs for mine. I really like the 2-2V carb set up. on the 300's. But I'm not going to spend $500 on a new intake. So I'm building my own. I've got less then $100.00 in materials ( building one out of steel ) in the intake manifold and I picked up two used Autolite 2100 2V carbs for well under $100.

You can pick up a pair of used 1987-97 300 EFI exhaust manifolds for $100 or less. These are basically two cast iron shorty headers. They flow much better then the stock carb exhaust manifold. And with some porting they can flow even more. And they don't have the headaches/issues that headers do.

Here's the outlet on a stock EFI exhaust manifold.


Here's the same outlet after I ported it. And doing this costed me nothing more then some time and a few dollars in consumables.




I love the 240! I've got 7 or 8 of them in storage right now. But I would stick with a 300 in a F250. In a car or half ton truck the 240 is a great choice. They make less torque but love to rev! Just look at the little 1V carb that came stock on the 240 & 300's . How well do you think a 302 V8 would perform with that carb! Get the 240/300 to breathe and they really wake up.

 

The 300 was a good engine to get you slowly from point A to point B . but if you want something to be fun to drive and sound nice there is no substitute for a v8. I'd stick to your original plan if I were you. FE or 385 series are both great engines and you could by a junker to get all the parts you need to do the swap.

 

Pretty cool work you've done there! Your slowly convincing me to continue with the 6. Couple questions, as it seems you've been around the block when it comes to these engines.

1. Could you tell me a little bit more about the 2 x 2V set up? I've read that a 600cfm carb on a stock 240/300 is a bit much for the engine. Wouldn't 2 2Vs be overkill as well? Obviously I am wrong as it is a popular upgrade, but I don't know enough about carbs to make sense of it. Just looking for some explanation!

2. How does one port an exhaust manifold? I've heard the term lots and I know a little bit about it, but have no idea how to do it. Is it difficult? I would like to learn these things while I have the opportunity.

 

This is why I have been on the fence. I wasn't sure if it would be worth the upgrades on the 6, but I might still go that route. As I said before, I've got two of these trucks that both have a 6, so I guess the F250 might need the 300 and the F100 keeps the 6