Anyone have experience using a 391 industrial block as in will it bolt in with same mounts and what what if any changes to crank. I am building motor for 68 Torino-the 390 block is at the machinist now but I can't help wondering if I should be using the other- also going to use Pro Gram cross bolt mains.
I'm far from an expert on this forum, but I almost did this myself. What I remember from it is that the FT block is virtually identical to the FE except for the distributor shaft housing diameter. The FT shaft diameter is larger than a normal FT housing diameter, but there are bushings readily available to bring this diameter down to standard FE diameter. Again, check on this info for accuracy but if memory serves me accurately this is the only difference between the 391 FT block and an FT block.
snout will need to be turned down to fit the standard FE timing cover that that you will need to use for your application. I believe the crank snout may also need to be shortened as some or all were longer to acommodate Industial accessory drives like air compressors for air brakes. the upside is you have a steel crank. Sure someone will correct me if I'am off on this. Mike
Instead of turning the snout down, what exactly is wrong with using FT front components?
October 26 2008, 6:27 PM
If you don't like the heavy cover and water pump, can a FE cover's crank opening be enlarged to fit the FT's snout? Sounds like an easier machining operation, with a quicker turn-around, than weakening the front of the crank.
The real question is why would you want a steel crank?
October 27 2008, 4:09 AM
If you are going to change crankshafts, why not do it to make more horsepower? A steel 391 crankshaft offers no reliability or horsepower improvement to a street driver. The machine work will set you back $1200 - $1500. What a waste.
Instead of that, why not get a 4.125" stroke crank from Survival? A crank / piston / rod rotating assembly runs right around $1500 and will add maybe 100 - 150 HP to an average 390: http://www.survivalmotorsports.com/Scathome.html
1912 Model T Ford touring Salmon (ugh!)
1913 Model T Ford Touring original Black paint
1915 Model T Ford Roadster Black
1915 Model T Ford touring Black of course!
1967 Cougar GT 390 Cardinal Red / Black
1968 Cougar GTE 427 Augusta Green / Saddle http://www.supermotors.net/vehicles/registry/15029/50071-2
the 391 crank is also different...the pilot hole is larger, and the area to support the flywheel......both require custom machining to be happy with pass. car applications
I looked into doing this a few years back when i built my Galaxie motor. I wanted to do a stroker street motor but there were very few options at the time. My engine builder found a 391FT in a local junkyard so we decided to do our experimenting on that and shelf my already-0.040"-over 428. Some 391 FT blocks have extra beef in the webs but other than the distributor hole it's basically a 390. The block is just fine for your ride. Take it home. The crank, however, was a different story as many have already mentioned. To use in my Galaxie we needed to turn the front snout down (front shoulder of the crank sticks out too far iirc), cut the end of the crank shorter, then redrill the balancer bolt hole and cut a new keyway. We didn't even take the crank out of the junkyard.
In my case i lucked into a 428CJ crank that had spun a couple of bearings and was in a junk pile. We cut the journals down and offset them to make our stroker. My combo used Chrysler rods but we ended up with custom pistons anyway so it is a FrankenFE. Like any one-off build we had lots of issues with getting all the parts to work together.
It was definitely educational but I would never do that much work again. Buy a kit from Barry at Survival or one of the other vendors on this list and you will be a happy camper. All the work has already been done for you.
Lowel, the FT stuff is just fine. Your block will need the aforementioned bushing, and maybe a plug where the air compressor drains into the block. Easy. And those cranks are really nice......and not as much of a problem as some folks think. But I would reconsider just for a moment. The cast cranks can take almost anything natural asperation can throw at them. Unless you're running a big roots blower or lots of N2O, the steel crank has extra stregth you don't need to have. I used to like the steel 391 cranks simply because they were steel, which to me meant that I could weld the beejeebers out of the rod journals and go to 4&1/4 stroke or so. I really don't like welding cast cranks. But now that you can buy a ready to go 4, 4&1/4, or 4& 3/8ths stroker crank, cast or forged- why ? You'd have to pay me, or someone else with a lathe, more to turn down the snout and re- key than you could buy a whole new crank for. Then more money to grind, weld, or whatever to get it ready to go. I certainly wouldn't throw a forged FT crank out as scrap, but we have easier options now. Cal
