I'm currently rebuilding a supposed 73 f250 5.9 360. And am ultimately looking to turn it into a 390. But I'm not sure what I have in the first place. I checked my crank and the only cast mark I can see is an "x" so im not sure how to identify what im working with. The ultimate goal is to build this motor for 6-7 hundred hp using a procharger super charger. Can you do this safeley on the stock block? I'm new to motors I just tore this one apart to learn more and get a sweet truck out of it. but I'm stumped on identifying my motor without any peices in the block to gayge tdc and what not. Any help us appreciated!

 

2U on the crank is a 390 crank. 2T is a 360 crank. Post 2:

https://www.ford-trucks.com/forums/1...-crank-id.html

600 to 700 HP supercharged Is possible. You would be better off going with a stroker crank out to 445 to start with, as that will give you a head start on power. Plus you should have forged pistons if you are going to supercharge it. along with better rods.

That said, you are building a motor with a potential for a fairly short life.

IMO this is not an engine for a first effort. They are not an unknown, but they are expensive to fiddle with.

Reading materials:

Building Survival Motorsports 445 Block Engine - Modified Mustangs & Fords

?Dyno Heard Round The World? Tells Backstory of Mark II 427 Ford Engines

 

 

The FE is still a viable performance engine with some versions having more potential than others, to wit:
The 427 is still at the top of the heap, especially now that you can buy a new cast iron or aluminum block that is vastly superior to the originals. Those blocks are not cheap so any project based upon one is going to be commensurately expensive. It is very unusual to find a serviceable 427 side oiler block at a decent price.
The 428 Cobra Jet is still very competitive in drag racing. NHRA accepts aftermarket blocks for stock and super stock. You cannot reliably overbore a 360/390 block to 428 dimensions. There are some shady characters who offer fake 428 blocks and engines created by over-boring a 360/390 block so beware. Again, aftermarket blocks (accepted by NHRA for stock and super stock) are the only cost-effective options.
There are plenty of good 360/390 blocks still available but you'll need a competent and caring machine shop to separate the sheep from the goats. Compared with the 427/428 blocks, this will be very affordable. The good news in this particular FE category is that there are some very good, cost-effective hi-po options to choose from. Here are two that will largely complete an FE engine:

1. Scat reciprocating assembly kit (includes crank, rods, bearings and rings) that can bring displacement to 445 or so
2. Edelbrock top end kit (includes aluminum CobraJet heads, cam, lifters, timing gear and Performer RPM intake)

This will produce about 500 HP on pump gas using only a 750-800 CFM carb. Survival Motor Sports can assemble all of these parts for you or assemble a complete engine.

 

I apologize for my Lack of knowledge but Hey that's what these forum's are for right! So what you're saying is I can take my 360 blocked in have it machined to accept a for 445 crank? Then swap to forged internals ect?

 

thank you but my issue is the "x" is the only cast mark I can find

 

It's actually easier than that. Your block only needs to cleaned and examined by your machinist to make sure it's worth messing with. For the 445 scheme that I outlined, he won't have to deal with the crank, rods, pistons or heads. The block may need to be bored. Keep that as far under .060" as you can. Once you know that the block is sound and how much it needs to be bored, if any, you can order the stroker kit. That kit will have forged rods and pistons but the crank will be cast, not forged. You can order the kit with a forged crank but that would be an unnecessary expense unless you are a hard core racer revving way past 5K.
Other optional operations that your machinist could carry out are 1) align boring the crank journals and 2) decking. These will correct any block problems that would diminish performance.

 

Thank you for sharing your knowledge! I really appreciate it.