gt40 running rough

i started with a cracked block, so i swapped over a f150 block and roller cam. Now that i got the engine back up and running i cant figure out why when i gas it, it just wants to bog down.
The idle sounds good. i checked the timming set it at 12, changed plugs, replaced the high pressure fuel pump, Anyone have any ideas what might be going on?

Here's a link to a thread with some timing discussion and a link to the GT-40 manual in the thread which should help you figure out your issue(s)

link

You're confusing roller cam with roller rockers but the concern over whether the ecu can compensate for the different cam is valid. Some folks are running Gt40p's (with a point more compression and a little better flow) without issue, others have reported a change as benign as a .030 overbore caused issues. So who knows.

It's the same thick film module that was came on the gt40. Would this need to be off the f150 because it's going to put out a different signal? I looked up the firing order and it looks to be the same.

There was another thread similar to yours that was looking at bad plugs, might be worth a shot, check to see if you have a cold cylinder or 2?

https://youtu.be/dV-GdmME4Sw

I think I got it. Now time for a water test

Mike9812121298 wrote: https://youtu.be/dV-GdmME4Sw I think I got it. Now time for a water test

So...............are you gonna keep it a secret?

https://youtu.be/d5kWbnia32E

So it started off running good. Good power, smooth then after the video after about 2 2.5k rpm it started to run bad again. I'm gonna check the timing tomorrow and make sure nothing moved. I'm thinking I need to check the LP fuel pump maybe it's not getting enough fuel and bogging down after it got warm

To Ken's point, if it takes a while to start running bad it could be something as simple as an obstructed anti-siphon valve.

So I've messing around with it this morning. I moved the timing down to 5 ran sluggish. Tried 10 a little better, tried 15 a little better, I kept moving it up until 35 and now it revs up and doesn't bog down. It sounds like it's running good. I've been reading that it shouldn't even run at 35. I must of installed something wrong when I put it back together? I checked for tdc and it lined up with the balancer marks

If you have 35 degrees at idle with the spout connected which is what I'd guess is the case, then you need to do some learnin" about how EEC-4 controls timing.

No load at idle, that would be pretty much an expected number.

Rev it up with no load and it'll drop Rev it up with load and it'll drop too.

The computer looks at all the inputs and varies timing accordingly. It's easy enough to have Google find you a typical timing table and you'll find that 35 degrees

How many times do different people have to mention the spout before you give an answer about your timing setting and checking method?

Sounds like you have 35 with it disconnected

So what's your timing with the spout hooked back up like normal?

When the spout is plugged back in, is the timing changing or is it stuck at 35 degrees?

If it doesn't change and stays fixed at 35 then it would seem like your signal from the computer isn't getting to the distributor.

If it is going up to 50 to 60 degrees...............that's a head scratcher and scary timing numbers.

Like you said, it shouldn't run or at least run without engine damage.

Strictly a guess here, but I'll say it's fixed at 35 and a bad sensor or the ignition module is the culprit.

Key word is Guess

Are you sure you know which cylinder is number 1?

Since I claim to know nothing about GT-40's, I'm probably at the end of my helpfulness if you want to call it that but I think you should check your MAP sensor.as a starting point.

Plenty of info in the manual but special equipment is needed for most of the testing, I'd try and dig up some local Ford guy with the right equipment.

Maybe Dreaming knows or can recommend somebody since he's from your area