I've got a 391 FT and have been searching for information about some upgrades that can be done but haven't found much. I know some stuff will fit from a 390 but realize not everything. What are some things you guys have done to get better performance out of the FT engines? I'm also interested to know where I would find some good headers for it. Doesn't sound like 390's will work so any help is greatly appreciated. BTW, this is for a large work truck (F750 flatbed) so I'm not trying to rebuild for racing or anything. Just want more power/torque for big loads.
Thanks!

 

Headers work best with high revving engines where moving a high volume of air is needed. FT manifolds are not a bad design and work well for the lower revving truck motor pulling big loads. I believe I have read that headers can aid valve damage when under load stress.

An electronic ign. upgrade like the Pertronix might be good, and some carb work. The FT is a work horse to start with.


Good luck


John

 

FT,s are limited to what you can do for power increase. There are no speed parts available for the FT. The factory exhaust manifolds are Ok , If your truck has single exhaust , duals with low restriction mufflers realy make a difference. If you have a points style distributor an up grade to electronic makes a big difference. Have the advance curve setup for maximum performance. The factory govenor Holley is a POS. Hard to setup and a major pain in the A**. Find a carb in the 600CFM range and tune it to your engine. Sometimes playing with carb spacers helps these engines. They seem to like a 1-2" 4 hole spacer. Cold air ducting to the carb realy helps. If you look around there are factory scoops and ducts available. On these engines little things mean a lot.Also if you remove the govenor --Get a tachometer and pay attention to it-- You don't want to overev your engine and damage it!!

Have A Good Day--------Hotwrench

 

How can I tell if it's Points or not? Where can I get the other ignition from? Thanks for the help. I was planning on upgrading the carb so this helps.

 

Bolt on a small-chamber set of FE heads (as long as they are smaller or at least the same size as the existing ones), an intake, use FE headers (if they don't interfere with bellhousing motor mounts or clutch linkage), and figure out what to do with the distributor - the FE dizzy is smaller diameter than the FT - you need a bushing to use an FE dizzy in an FT - but not sure if you need to do that with the FE intake. However, you would need to do something about the dizzy gear/oil-pump shaft. Just change the gear?

You'll wind up with a low-compression engine, but what the heck

 

I'd agree with HOTWRENCH on the heads and exhaust. These motors were built to be durable in their applications (long, hard, heavy pulling at lower rpms) Using FE heads in an FT application could be a recipe for dissaster when it comes to the heat and pressure exerted on the valves. If you really want to try headers, just bolt em on the FT heads, I think the bolt patterns on the ports are the same (could be wrong though) You'd just be leaving the exhaust crossover open. Seems to me that that doesn't intersect the ports internally like the FE heads do. Otherwise why would they extend to the exhaust face ?

 

Use an FE intake with FE heads, no crossover problems.

As for "pressure exerted on the valves" - um, I have no answer for that one. Seriously...

Using that rationale, an FE 390 would burn up the instant I put a 10K load on my highboy ...

 

The FT's GVW ratings were far and above what a 10K load in a 4wd would be. You're talking about up to 11,000 lb on the steering axle, plus 20,000 for a single axle truck or 34,000 lbs for a tandem. And thats not counting pulling a trailer. You're talking a LOT longer time to accellerate a load to highway speeds or trying to maintain speed on even a slight grade, that's a lot more heat being generated and pushed out the exhaust valves. If the FE valves could handle that, Ford would have never come up with the FT heads and valves. I turly think he's playing with dynamite here. If he wants more out of his truck, he needs to upgrade to a diesel. Th eFE/FT's are good engines, but they have their limitations in this case.

 

Baddad is correct FE heads wont hold up on a heavily loaded FT, FT heads have rotators to help cool the valves. Many have sodium filled valves for durability with induction hardened seats. A costomer of mine tried the FE heads on a FT he got about 2500 miles out of it ,then we had to pull the heads again. Receded the valves up in to the seats , valves looked like tulips. The factory exhaust manifolds are the rams horn design and i dont think headers would make much difference under the 4000rpm limit. These engines make there best power from 2000-4000 RPM any thing that can be done to fine tune in this range will be benificial.

Have A Good Day -----Hotwrench

 

Green, If you have a '72, you have points. I would look at a Pertronix kit as the replacement. Quick and easy. Headers will help any engine, but the rpm range you will be running in, they won't help as much as they do for the higher rpm guys. They might not be the best bang for the buck. IIRC, the exhaust flows through the ex ports, then into the manifold, and then back into the head for the crossover on an FT......I'm thinking you could use pickup headers or shorties and the crossover ports would just sit there empty and not hurt anything......does your truck have a 4 barrel intake ? If not, how about an edelbrock performer ? I almost never recommend a performer, but your rpm range might just be the right place for it. The bolt holes will line up, and the ports ought to be okay, though the cross ovvers will be blocked. I don't know what your thermostat mounting area looks like however, you'll have to examine the setup you have now and look at a picture of a performer and see if you think you can mount something up on your hoses. I'm certain your camshaft is very small. Howabout a swap ? A bigger cam, with the appropriate valvesprings should make a huge differance. You might need to set your governor to a higher rpm....do you know where it is set currently ?
You can also swap to the FE 390 heads and intake together, but you should have valve seat inserts installed- the soft seats in most FE heads won't live under FT style use, and the induction hardened seats in '72 or later 360/390 won't either- you would need inserts like the FT heads got from the factory. Fourtunately, those are available in every size you can think of. But I think resetting the gov. and a new cam/lifters/springs would be what I would do first. DinosaurFan, on 'work's old cast off 'puter

 

Headers might be worse, the small exhaust ports dumping into a big port header, would mean the exhaust charge would slow considerably. Might be worse than the stock logs

Dino, for the intake, an FE intake's ports would be huge compared to the FT heads, wouldn't it?

 

Krewat, the factory logs are just about as bad as it gets. I would try headers if it were mine. On the intake side, the size of the port is the same at the gasket face- I think ford was trying to not have to make a new gasket part number- as the later velocity style ports in the FEs. I'm thinking the RPM or the blue thunder might well have too large a port, but the performer 's ports ARE on the small side, I'd try it. DinosaurFan, on work's old 'puter

 

I guess none of y'all have seen the FT's manifolds..................Not the crappy logs the FE's got. They're more in the line of block hugger headers. Not nearly as restricted as the FE's got, that includes the CJ stuff.

 

I would say find a 390 and build it how you want and do an engine swap. It will save ya some down time and keep your old truck running until then!!! But remember its a HD truck and why the hop up parts? I would just leave it alone if it was me......JMHO

 

Maybe the exhaust manifolds are pretty, but the exhaust (and intake) port sizes on the FT's are atrocious