First 390 build

[Gaugster]

   
   Actually I built a fan shroud for it. It's not super pretty but does the job.

Nice. It's DIY so always a plus.

[KMcCullah]

 Sweet truck with a healthy 390. It's has to be a blast to drive around town with the short tire/4:11 combo. And it's a Twin I Beam to boot! A Gear Vendors OD would make it a cross country cruiser.

[My427stang]

If you haven't got your tuning answer yet, I would set total timing to 36-38 degrees vacuum disconnected, raise RPM until it stops advancing), then see where your initial ends up at idle

Set carb a/f to best idle, reset idle speed and make sure the vacuum advance isn't energized at idle.  if it is, add some secondary idle to close the primary throttle plates. Then connect vacuum to a ported source

That should be pretty good with what you have, if you knew the curve in the distributor, there may be some gains there too if it's conservative

[DubyaTF]

If you haven't got your tuning answer yet, I would set total timing to 36-38 degrees vacuum disconnected, raise RPM until it stops advancing), then see where your initial ends up at idle

Set carb a/f to best idle, reset idle speed and make sure the vacuum advance isn't energized at idle.  if it is, add some secondary idle to close the primary throttle plates. Then connect vacuum to a ported source

That should be pretty good with what you have, if you knew the curve in the distributor, there may be some gains there too if it's conservative

   This answers it for me; thanks very much! This order makes more sense so I can sort of figure out where the curve is at. I have a good idea that it comes in quickly so we'll see as we tinker.

    Only other question I've wondered is the oil pressure at 25psi hot idle. There's no oil restriction jets in the heads for the rockers and I'm running a standard volume and standard pressure Melling pump. It'll run 60 psi when cold at idle and everything seems happy throughout so just curious to others experiences.

    Thanks again to all for your feedback and compliments. I'm head over heels about the truck that I'm already looking for a '61-'64 F100 to build into a gasser with a 4 speed. Insane I know.

[My427stang]

25 psi at idle and climbing with throttle is plenty, but nothing wrong with adding some restriction in there. 

[DubyaTF]

  Having had a lot more time, I've spent it with my truck's carb. It was dead rich, black smoke rich on cold start and I started with a timing and power valve change along with a fresh set of Autolite 45 plugs gapped to .035". Typically a low vacuum reading means a leak in the intake somewhere right? Any good techniques to find leaks without spraying flammable stuff all over my engine? I have a solid 3hg at hot idle and it'll jump consistently with rpms.  At first I thought my vacuum gauge was broken. I just wonder what's the likelihood that the cam could be causing low idle vacuum? It's the XE274 installed dot to dot with C8AE-H heads making 10.25:1 compression. Thanks in advance for your feedback and stay safe friends!

[blykins]

  Having had a lot more time, I've spent it with my truck's carb. It was dead rich, black smoke rich on cold start and I started with a timing and power valve change along with a fresh set of Autolite 45 plugs gapped to .035". Typically a low vacuum reading means a leak in the intake somewhere right? Any good techniques to find leaks without spraying flammable stuff all over my engine? I have a solid 3hg at hot idle and it'll jump consistently with rpms.  At first I thought my vacuum gauge was broken. I just wonder what's the likelihood that the cam could be causing low idle vacuum? It's the XE274 installed dot to dot with C8AE-H heads making 10.25:1 compression. Thanks in advance for your feedback and stay safe friends!

That's a small cam.  It's not causing low vacuum.  That cam should have 16-18 inches of vacuum.

[DubyaTF]

   Thanks for the wisdom Brent. I wasn't 100% satisfied with how the intake settled during assembly.

[Twinibeam66]

Sharp Truck !!!

[wayne]

I like your truck my go to gear is a 3.70 i run them in all my street stuff.

[fryedaddy]

when i changed to a rpm intake,the first time i was conservative with the sealer i used.it sucked oil and smoked so i took it off and the second time i used a little more sealer and it still smoked and used oil but nowhere near as bad.third time charm.i used a generous amount of sealer and it sealed great.no smoke,no oil use.

[DubyaTF]

   Even with my novice tuning abilities, it for sure hustles down the street. I'm sure it needs a taller tire. Perma-grin is a good thing!

[fryedaddy]

   Thanks for the wisdom Brent. I wasn't 100% satisfied with how the intake settled during assembly.

i didn't read it all but did anyone suggest re-torquing  the intake.i drove mine a time or two then re torqued it.

[Adam Dice]

The vacuum with my XE274 cam on my 428 and 875 idle rpm at 3300 ft elevation is about 10".  Just as a point of reference.  That is similar to others that I have talked to with the same cam.