1987 F-250 7.5l 4BBL bored .030 over, 0 miles on rebuild. 4-speed transmission. 4x4.

Electrical engineer by day, shadetree mechanic by night. Bought this truck for a project truck and decided to rebuild the engine before I ship out to the Air Force (Officer Training School). Pulled the engine, had it bored .030 over did a 30 minute break-in and noticed some oil leaks. Break-in was uneventful but successful. Pulled it again, replaced rear main as well as sealed some overlooked bolt holes that went to oil. I am no expert (especially with carburetors) but I am very mechanically inclined. Here are my issues and attempted fixes:

Oil Leaking from rear of engine, drips appear to come from inside bellhousing.

• Enough to cause a concern but not a steady flow.
• Found that the top left bellhousing bolt hole went to oil, threadsealed.
• Checked 2 oil gallery plugs, were tight.
• Replaced rear-main using FelPro seal and a method to set to 25 thousandths crush depth. Offset 3/8" and used RTV Black.
• Oil is not coming from the sending unit, pressure reads around 80psi using a new Auto Meter Gauge

Headers cherry red at ~ 2k RPM.

• Initial break-in was done outside, this could have been happening during that time but did not notice until running it indoors last night. This was the first start-up after break-in and reinstalling engine in chassis
• Timing is set at 10* BTDC using a light at idle, vacuum advance plugged
• Edelbrock 1406 was rebuilt by myself following the enclosed instructions carefully
• Ignition is brand new MSD distributor, Digital 6AL and coil.
• Headers become red before engine reaches operating temperature

Clutch will not release (The majority of my frustration)

• New 12" clutch kit was installed (including a new flywheel)
• New Master and Slave cyl was installed (twice each)
• System was bench bled for HOURS using almost any method offered online
• System was bled in truck for even more hours using more methods found online
• Firewall has no flex, the MC arm lands on the clutch linkage smoothly
• Slave appears to extend the 0.53" that manufacturer recommends
• No bubbles, pedal feels 80-90% firm. No leaks from system.

I appreciate anyone whom took the time to read all of this! I hope I can have it running before too long.

 

The edelbrock 1406 is only a 600 cfm carb with vac secondaries, so it's prob running lean at cruise speed with only the main barrels open. I think a 750 cfm with vac secondaries would make the 460 much happier

 

I believe that it is lean as well. I think first off I should try to richen it up. I actually bought an AutoMeter wideband o2 gauge right after I posted this and will have it installed tomorrow along with the kit to properly tune the carb. Will report back on that aspect.

 

I'm not sure richening the mix will boost the performance very much but anything free is worth a try

 

I can't help you with the clutch but I've experienced the other issues. I rebuilt a 302 and had over tightened my adjustable rocker arms.If your arms aren't adjustable this isn't likely what happened unless machining of the block or heads have essentially made your push rods too long. My headers glowed until I got this and my tuning sorted.

Unless your a full time Mud Bogger ,keep your 600 CMF carb. I have a brick shaped 85 E350 4x4 van with 3.55 gearing and an all stock 460. CFM calculations which can be searched call for 532.07 CFM at 4000 RPM. I live near central California(regular 80-100+ temps) and have great throttle response,decent MPG and good power all while passing smog. I haul dirt bikes and camping stuff in the thing and rarely see 4000 RPM. Even with headers, unless you're really revving it out, you shouldn't need more.

Next thought. $300 aluminum radiators really help as well as functioning fan clutch!

 

Appreciate the response! Quite a bit has happened since I posted this message:

The clutch issue was sorted out after leaving it depressed overnight then doing some minor bleeding. Finally drove it yesterday!

My rockers are fully adjustable as well as I measured intake and exhaust pushrods so they should all be fine. I put in an o2 sensor and found that I was running a bit rich. Tuning the carb over the course of this week and will look at engine temps / header color maybe this weekend after it has had some heat cycles under load.

I agree with the CFM of the carb, I calculated mine to be ~650 which is what that carb supplies. Florida weather so 90-100 is the norm! Just glad that I don't need to pass emissions.

I did put an aluminum radiator in there, still need to check the fan clutch. I believe it to be working but I can't remember definitely seeing it run.

Finally, what's a post without a pic of the goods?!