Vacuum Secondary Conversion
- Thread starter 340inabbody
- Start date
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All I can add to that is, If I can figure it out (and I did) a chimp can do it.
I'd believe you'd be considered way above average, especially since you help the average guy on the regular here.
4eighteener
Well-Known Member
What are chimps and average dudes figuring out?
Read what, and ask questions to who?
That is what I have asked here for someone to post their unicorn build that is running 195-200 psi on the street with pump gas and cast iron heads. Is the ignition severely retarded, cam timing?
The only advice that has been given so far is increase the radiator size
Read what, and ask questions to who?
That is what I have asked here for someone to post their unicorn build that is running 195-200 psi on the street with pump gas and cast iron heads. Is the ignition severely retarded, cam timing?
The only advice that has been given so far is increase the radiator size
I think I’d take a few steps before I jumped right into how much cr I could get away with.
With my if I ever upgrade the short block on my 380hp 5.9l crate I wouldn’t shoot for the stars, I start with a cr that’s generally known to work for the combo, and still might shave off a few decimals just in case.
4eighteener
Well-Known Member
That sounds like a good plan!
Do you think you would keep the factory heads, or upgrade at the time?
I tend to like AJ's build posts because he can run the numbers methodically and can tell what works with the current engine building goal posts. I wanted to find out if those goal post have been moved, and if so, how we can put numbers to it to quantify.
I have no immediate plans but at some point I’d like to see what I can get out of the magnum heads 1st and go from there, would like to pickup a roller 360 and zero deck with forged pistons. I want to keep the magnum short block stock, it barely has any miles on it.
Newbomb Turk
Well-Known Member
Because to type it all out takes forever.
I may make a series of videos when I put my garbage back together but I’m not the only one out there doing it.
See if you can get RustyRatRod to type it out. He didn’t know how to do it, so he asked questions and figured it out.
And in my case as the OP I was dealt an existing engine that was reinstalled in my car. Worked on it a bunch, made it run better but wanted to continue to try and improve its performance but moreover provide me more headroom in not detonating. Just because I can’t hear or feel it detonating does not convince me I am not especially in corner cases such as high loads AND EXCESSIVE heat here in the desert.Oh and shitty fuels…
What I have initially done was:
1. Add aluminum radiator with duel fans and shroud
2. Add a 160 thermostat
3. Went from a 2:73 rear to 3:55
4. Disconnected my heater core (for other reasons)
5. Retard all in timing and slow the curve down.
6. Single to duel plane manifold in process
7. contemplating going to VS set up.
8. Planing on an eventual rebuild to lower compression and change cam since I don’t know what’s even in there.
What I have initially done was:
1. Add aluminum radiator with duel fans and shroud
2. Add a 160 thermostat
3. Went from a 2:73 rear to 3:55
4. Disconnected my heater core (for other reasons)
5. Retard all in timing and slow the curve down.
6. Single to duel plane manifold in process
7. contemplating going to VS set up.
8. Planing on an eventual rebuild to lower compression and change cam since I don’t know what’s even in there.
It's like anything else. Welding, drilling and tapping and on and on. My attitude has always been if you are going to own an old vehicle, you need to learn to work on them yourself. It's not like it's a big mystery. The ones that get me are those who cry about having to buy a special tool, use it once and then sell it. Or rent it. If you have plans to keep the vehicle, then keep the tools. I have well over forty years of tools accumulated in seven boxes and in various blow molded cases. Maybe overkill for a do it yourselfer. I did do mechanic work for a living, after all, but nonetheless, I don't get rid of tools. I bet cavemen didn't sell their flintrocks.
4eighteener
Well-Known Member
340, sounds like the previous owner must have built it with more stip than street intentions.
You have good parts, the distributor should work well even on the street. Easy to adjust advance rate with different springs and total advance.
Many people run a dp on the street. Probably not optimal for a daily driver. Someone suggested the avs 2, which is a great street carb otb.
Yeah, you may have to get in there for an exploratory to determine piston and cam choices, I would be interested in hearing about what you find.
Sorry that your thread was high jacked a bit, it just headed that way
You have good parts, the distributor should work well even on the street. Easy to adjust advance rate with different springs and total advance.
Many people run a dp on the street. Probably not optimal for a daily driver. Someone suggested the avs 2, which is a great street carb otb.
Yeah, you may have to get in there for an exploratory to determine piston and cam choices, I would be interested in hearing about what you find.
Sorry that your thread was high jacked a bit, it just headed that way
Sometimes the old adage "if it ain't broke, don't fix it", goes a long way. Now Daddy, for instance, took it to the extreme. With his 65 Falcon, rather than change the oil at the correct intervals, he'd just add in another container of STP Oil Treatment. Yeah, after twenty years of THAT, guess who had to clean it up and build it?
On a 4160 Holley (vac sec)
There is still a spring kit of 10 different springs to adjust the opening rate of the vac sec diaphragm
I've seen 750 , 4160 's tuned with the springs that you could barely detect the opening of the secondaries
There is still a spring kit of 10 different springs to adjust the opening rate of the vac sec diaphragm
I've seen 750 , 4160 's tuned with the springs that you could barely detect the opening of the secondaries
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