New to me engine

[Pvmt-Pndr]

Update and questions.

The truck fires right up whenever I hit the key. It sounds pretty good too. Once in a while I'll get a pop out of the exhaust. I can't really touch the gas pedal until it's been running for a minute otherwise it stumbles, once it's over that it has great response sitting there.

I've only driven it a couple of miles since I had a long list of things to do to it but that list is short now. I don't have a plate on it but plan to do that this coming spring. This truck does not like to rev. Once I hit my higher gears it is very slow to gain speed. I have good fuel pressure, new plugs/wires, headers, full 2-1/2" exhaust all the way back with an H-pipe. It is still timed at 8 degrees and I hooked up the vacuum advance so at idle it's at 12 degrees. Even with the 4 barrel feeding the motor with everything it has it takes a country mile to get to 45 mph.

What I have yet to do is replace the cap/rotor. I'm running the HEI cap that came with the first motor. I think this is a good place to start to find my power loss but any suggestions beyond that?

[geezer#99]

What’s the fuel pressure at?
Strange hooking up the vac advance only added 4 degrees to your initial of 8.
Which port on the carb is your vac hooked onto?

[Pvmt-Pndr]

Fuel pressure is at 5-6psi.

Vacuum advance is hooked up to the left port on the AVS2.

[geezer#99]

That means you’re hooked to ported vacuum.
Getting enough vacuum to add 4 degrees timing tells you that the idle screw is adjusted up too much. Carb is idling on the power circuit. Idles rich.
Hook the hose to the right port. Idle will increase. Then adjust the screw back out.
That could be the cause of the stumble.
That should help ir run better.
Then try more initial.
Bump it up to 12.
See what that does.

Are you still using the original valve springs?
Low power is a symptom of weak springs.

[vince1]

I think I would measure the cam lift on each individual rocker just to rule out the possibility that a lobe could be beginning to wear. I'd also set the valves with the engine running. I found mine a bit tight after following one of the suggested methods prior to it running.

I've had a really old corroded up cap on the 250 HEI. It didn't seem to bother it at all. More likely could be a plug or wire off a bit. It's a bit of a hassle but did you try removing plug wires one at a time?

If it doesn't like to rev hopefully a little more advance will fix it. On the other hand I have noticed on my 350 that it doesn't like too much advance. It revs really nice to a certain point and then doesn't like it at all. Most of my timing is by ear though and I feel that after 3 or 4 tries it gets pretty close to optimum.

I hope you get it running well. I see one out in Canmore with a well drilling rig on it. Another is parked next to the highway with a sign advertising trees. It's nice to see the old big trucks still being useful.

[Pvmt-Pndr]

Geezer :
Everything internally is original to the "new" motor. After measuring the bores, doing a compression test and seeing what looked like a fresh machined engine I figured all was probably well.
I'll swap the vacuum line over and see what happens. 12 degrees sounds like a lot for a tall deck from what I've read. Then again I don't claim to be an engine builder but I know my way around them enough to be dangerous.

Vince:
I tried one way I found on the internet and it was a fail adjusting the valves. I tried it twice actually. I ended up doing it another way and it's been running somewhat good. That's why I was pointing toward the HEI since I have lots of time to troubleshoot while I'm at work. I haven't verified the plugs and wires are still good. I assumed they are since they have roughly 3 total hours of run time on them mostly at idle.

I don't know if it'll help trouble shooting but the truck will rev faster in the lower gears. Keep in mind I have a 5 speed with a 2 speed rear end. 5H is 1:1. 1,2 and 3rd gear it revs pretty decent. Once I hit 4th and 5th gear she falls on her face. I just assume the power loss isn't as noticeable because the gearing helps cover it up. I can't imagine 50 years ago guys using this same engine to pull 30-80k pounds at least not the way mine feels to me.

I haven't been able to put it to use quite yet. I work a lot and have been chipping away at things when I have spare time. I will have it plated this coming spring but while it's still warm out I'd like to resolve the issues it has. Once it's all worked out I'll move onto making it the truck I want it to be cosmetically.

I appreciate all the help!!

[geezer#99]

Maybe in 4th and 5th your secondaries aren’t opening making in run on only te front 2bbl’s.
Might try adjusting the air door a bit richer.

What rpm are you running in 4th or 5th.

[Pvmt-Pndr]

They're definitely kicking in, I can hear them when they do.
Trying to get it to spin more than 2700 rpm or so is almost uncomfortable. It feels like I'm over working the motor in 4th and 5th.
I don't use 1st gear in the truck because there's no need to, 1st is good for about 3 mph. I take off out of second gear and shift to 3rd gear almost right away. I'm in 4th gear around 25 mph.

I have another tall deck in my arsenal but the other one one is a 366 and I've spun that to 4500 before it felt like my 427 does. The 366 doesn't run out of steam until about 4300 rpm. It's an apples to oranges comparison because the 366 is in my wife's mud truck.

[geezer#99]

What’s your timing curve like?
How much mechanical timing?
All in by what rpm?

At 2700 you might only have 25 To 30 degrees total.

[Pvmt-Pndr]

This engine used to be governed to 3200 rpm. My original engine was also governed to 3200 with the same HEI but the carb was stock. They both rev very similar to each other even with a bad cam in the first motor.

I don't know any solid numbers for my mechanical timing. I'll have to put a piece of tape on the pulley with timing marks on it since I can only see up to12 or 16 degrees and it goes beyond that when reved just off idle.

I believe it is all in at a low rpm. I changed the mechanical springs to the lightest ones that came in the kit while the distributor was still in the original motor.

I get a day off tomorrow for the first time in 2 months so I'll be able to hopefully answer all of your questions tonight or tomorrow

[Pvmt-Pndr]

Originally Posted by geezer#99

That means you’re hooked to ported vacuum.
Getting enough vacuum to add 4 degrees timing tells you that the idle screw is adjusted up too much. Carb is idling on the power circuit. Idles rich.

You nailed it right here! Since it has idled more than anything with the screws adjusted out too far it basically flooded itself constantly. I made sure the timing was at 8 degrees again. Pulled all the plugs, cleaned the carbon or gas off of them and stuck them right back in. Hooked up my vacuum gauge set the mixture screws correctly. Rehooked the vacuum advance, now I can't tell how far advance it goes. It runs smooth. I took it for a ride and was able to spin it to 3500 rpm without any hesitation whatsoever! This truck hauls some ass now! Thank you!!

[Pvmt-Pndr]

ROUND 3:

I took the old girl out for a Sunday ride last week. Everything was right in the world and she ran like a scalded dog (for what it is). When I pulled back into the driveway she went up in flames. I got it all put out and though it's a buzz kill because of how good it was running after all this time, it's not a total loss. It cooked the paint on the top of the hood, I was planning on painting it anyways. Wires are all junk along with some hard lines and a lot of rubber.

The distributor is melted beyond me messing with. I've been doing a lot of reading on a distributor for this truck and can't come across a definite answer if a standard BBC distributor will work or not. I've read that a standard one will work with hei as long as it's a tall deck block and a tall deck manifold. Then I've read the opposite too. Any solid answer?

I'm also debating going fuel injection. My edelbrock doesn't seem to have been bothered by anything but will get a rebuild if I don't pull the trigger on injecting it. Anyone have any reviews on a good fuel injection setup?

[cadillac_al]

What started the fire?

[Pvmt-Pndr]

I'm not 100% sure and never will be because any evidence was burnt up. It could have been my pressure gauge or fuel filter I had under the hood. Everything was brand new including the fuel lines and ss clamps. I'm guessing there was enough gas to make its way down to the header, at least that's what the little bit of evidence I can see shows that happened.

[geezer#99]

Sad to hear that!
I’ve had that thrill before. Popped the hood just in time to see fuel boiling on the intake then wooosh!
Here’s likely the best hei you could use.
You need one for a tall deck. Standard deck is too short.

https://www.summitracing.com/parts/dui-13720bk

[Pvmt-Pndr]

Thanks! I also asked these questions in my build thread. I wasn't getting answers quick enough so I asked here too. It seems the standard distributor will work on a tall deck with the standard tall deck manifold (which I'm running). I guess it becomes a problem when guys run tall deck blocks with standard deck intake and spacer. Please correct me if I'm understanding wrong.

[geezer#99]

IIRC the standard deck doesn’t interchange with the tall deck distributor.
Easy to check.
Measure from bottom of distributor gear to the flange on a td and a standard deck. Or even measure a sb as it’s same as bb standard deck.

[Pvmt-Pndr]

I'll measure it when I get home tonight. I thought about doing that yesterday too but don't have access to a standard deck distributor.

[sweetk30]

The 2 stock c-60 366 BBC intakes I have are cast lower in the dist section for stock height dist use .

[Pvmt-Pndr]

6-5/8" from the collar to the bottom of the gear. Anyone have one laying around they can compare that measurement to?

[Pvmt-Pndr]

I took the chance and bought one, as sweetk30 said they do interchange. There's a little more to it than that though. I had to cut the "flat head screw driver" end off of the new distributor and reuse my original gear. My oil pump has has the flat head screw driver end on it while my distributor fits around it. It is backwards from the standard oil pump from what I have found. This is the best picture I could get, top is my original gear and bottom is what came with the new distributor.