Making a '75 360 run right...
Thread Starter
|
New User
Joined: Aug 2003
Posts: 4
Likes: 0
Making a '75 360 run right...
Hey all! Just finally found this site. My buddy and I are fixing up his dad's old truck.
It's a '75 F100 with a 360 and a 4 speed tranny. 4x4, manual hubs(not sure if factory 205, or a conversion.) and it has a few modifications.
The motor has a 4 barrel carb and intake on it, as well as headers and dual exhaust. The motor sounds pretty cammy, but to my surprise, it won't go over 3000 RPM. Whats going on!?!?!?!
I have most my experience based with Mopars and if we had this types of mods on our rigs, we could run right up to 5000 RPM without any major problems, so what is going on with this ford?
I would think it should still make great power, even though FEs aren't that great a motor. Is it Ignition? What do we replace? I would like to have the distributor curved for better performance, so what should we shoot for as far as ignition timing?
Thanks guys!
Andrew
It's a '75 F100 with a 360 and a 4 speed tranny. 4x4, manual hubs(not sure if factory 205, or a conversion.) and it has a few modifications.
The motor has a 4 barrel carb and intake on it, as well as headers and dual exhaust. The motor sounds pretty cammy, but to my surprise, it won't go over 3000 RPM. Whats going on!?!?!?!
I have most my experience based with Mopars and if we had this types of mods on our rigs, we could run right up to 5000 RPM without any major problems, so what is going on with this ford?
I would think it should still make great power, even though FEs aren't that great a motor. Is it Ignition? What do we replace? I would like to have the distributor curved for better performance, so what should we shoot for as far as ignition timing?
Thanks guys!
Andrew
Junior User
Joined: May 2003
Posts: 57
Likes: 0
Making a '75 360 run right...
What happens at 3K? Does it sputter, miss, or just plain not rev any higher? It's either a carb or ignition problem. Try a different carb first. I would also change plugs/wires/cap as good practice. I assume it's a duraspark unit which should be fine. Make sure the coil is kicking out enough juice. For a timing curve, I would run 12 initial with 26 mechanical in the distributor, all in by 2500rpm. Make sure there's not detonation though.
Senior User
Joined: Apr 2003
Posts: 426
Likes: 0
From: Knoxville, TN
Making a '75 360 run right...
Hmm, you actually double posted this, or was it two forums and they moved it?
anyway, I'll double post my reply as well.
Dang brother I don't know if I'd have said that!!! 
Let us see if we can help you out anyway
First if the 75 does not have DuraSpark electronic ignition (can’t remember if it was 75 and 76 or just 76) I’d at the very least make sure it is in tip top shape (points, condenser and all that) or convert it to the crane xr-i or pertronix or DuraSpark.
Second, if it sounds CAMMY and the ignition is working properly, I’d start looking at valve springs. People will stick cams in and not replace valve springs, each time they float the strength decreases and you lose BIG power. In addition, if the timing chain was not replaced, its probably killing the cam and the timing, they have nylon gears which is no good.
Getting 350-400 horsepower should not be much of a problem with a cam and some flat tops. If you stock pistons are in good shape, they may actually be 410 pistons and you could run a 428 crank for a 410 with decent compression.
anyway, I'll double post my reply as well.
Originally posted by F100Racer
The motor sounds pretty cammy, but to my surprise, it won't go over 3000 RPM. Whats going on!?!?!?! ..........
...............................................
I would think it should still make great power, even though FEs aren't that great a motor. Is it Ignition? .....................
The motor sounds pretty cammy, but to my surprise, it won't go over 3000 RPM. Whats going on!?!?!?! ..........
...............................................
I would think it should still make great power, even though FEs aren't that great a motor. Is it Ignition? .....................
Let us see if we can help you out anyway
First if the 75 does not have DuraSpark electronic ignition (can’t remember if it was 75 and 76 or just 76) I’d at the very least make sure it is in tip top shape (points, condenser and all that) or convert it to the crane xr-i or pertronix or DuraSpark.
Second, if it sounds CAMMY and the ignition is working properly, I’d start looking at valve springs. People will stick cams in and not replace valve springs, each time they float the strength decreases and you lose BIG power. In addition, if the timing chain was not replaced, its probably killing the cam and the timing, they have nylon gears which is no good.
Getting 350-400 horsepower should not be much of a problem with a cam and some flat tops. If you stock pistons are in good shape, they may actually be 410 pistons and you could run a 428 crank for a 410 with decent compression.
New User
Joined: Aug 2003
Posts: 7
Likes: 0
From: Eugene, OR. USA
Making a '75 360 run right...
It acutally has an aftermarket tach on it that has a permanent arrow pointing to 3000 rpm. When I rev it it just goes to 3000 and stays like it has some sort of rev limiter.
Cargo Master
Joined: Aug 2000
Posts: 2,931
Likes: 12
From: SW Michigan
Making a '75 360 run right...
My first thought would be the valvesprings, if they are the stock springs they could be pretty tired, especially if the cam has been changed. The ignition in a 75 or 76 FE would be the Duraspark, if it is all there working properly, it is most likely not the cause of your problems. And check that tach....there are some aftermarket tachs that have a rev limiter function built in. Maybe some old guy (like me ) set the limit low to keep his kids from getting into too much trouble when they drove their Dad's truck.....DF
Thread
Thread Starter
Forum
Replies
Last Post
parkland
General Diesel Discussion
140
Sep 24, 2016 12:47 PM
TheGermanGuy
1973 - 1979 F-100 & Larger F-Series Trucks
5
Jan 31, 2016 02:06 AM
JC75F250
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
2
Jan 5, 2015 10:34 PM
MagickNinja
1967 - 1972 F-100 & Larger F-Series Trucks
10
Feb 23, 2010 11:30 PM
