Looking for DAVE who is good with HEI re curve

[oldblue1968chevy]

Another member said to look for DAVE who is good with HEI.

Please msg/PM me dave thanks

[prostreetC-10]

Might help to get his board ID

HEI recurve sounds like the latest hunting bow! Sorry.....got hunting on the brain!

[oldblue1968chevy]

His board ID is dave 454 or HEI or something (another member told me this) lol

Right now my initial timing with no vac adv is 14 wot no vac adv is 36 (give or take a tadbit).

What should it be when i plug vac can in?

I have mr gasket weights and 1 light 1 medium spring

[prostreetC-10]

Might be this HEI451 guy.

[HEI451]

Yes, it IS "this HEI451 guy". But, it ain't, it IS HEI451, thanks.

Please outline the engine particulars, size, comp ratio, cam duration, intake and exhaust system, drive train, chassis it is in, and we can go from there.

What it sounds like this topic will evolve into, when you plug the vacuum advance into full manifold vacuum, the timing goes bonkers, adds a bunch of timing, correct?? That ain't the way it should work.

Lets go over what you have, and we can get it dialed in for you, possibly, without sending your distributor to me.

Also, I turned my P/M OFF, I don't like 'em, I don't have anything on any board that is so secret, it can't be said/printed right out in the open.

[Marv D]

LOL, see I told ya he'd be easy to find even if my foggy memory was only 'close'

[prostreetC-10]

Originally Posted by HEI451

Yes, it IS "this HEI451 guy". But, it ain't, it IS HEI451, thanks.

huuuuuuuuuuuh???

[oldblue1968chevy]

1968 C10 LWB 3.73:1 3spd manual transmission (on the column),
350 bored .30 (355) , ram horns, glasspacks (2" or 2 1/4" diameter pipe) , edelbrock 600 1406 , edelbrock performer rpm aluminum intake manifold, 9.5:1 (Maybe a LITTLE less, gotta run 93), We installed cam 'straight up' with the dots on top of each other

Part $ 12-600-4 S/N$ VI7546-10
Engine: Camshaft, CS 279T H-107 T Thumpr
Miller auto machine
Grind #: Camshaft, CS 279T H-107 T thumpr
SPC INSTR 1:
SPC INSTR 2:


CAM CARD:
intake exhaust
Valve adj HYD HYD
Gross valve lift .479 .465

Duration @ .006 tappet lift 279 297
valve timing open close
@ .006 INT: 36 BTDC: 63 ABDC
EXH: 76 BBDC: 41 ATDC

These specs are for cam installed
@ 102.0 intake center line
INTAKE EXHAUST
Curation @ .050 227 241
lobe lift .3190 .3100
lobe separtation 107.0

[oldblue1968chevy]

I got it pretty close I think runs alot better than before like I picked up 100 hp lol

I'll re check everything tomorow and get back to you on my current timing etc etc

[Lee H]

Humm, I'll be watching this. I'm betting that 14 is a little high with a heavy pick-up Assume you running 93 because it's pinging?
Posted via Mobile Device

[HEI451]

OK, this should help it.

Initial timing, vacuum advance disconnected: 12 deg/BTDC, idle speed at or below 700 rpm's OUT OF GEAR.

Mechanical advance curve: 22 crankshaft degrees, for a total of 34. This is done with a stop bushing on the limit poin on the underside of the rotor holder on POINT TYPE distributors. For the large, coil in cap HEI, wrecking yard parts will be needed, with center plate marked "375", weights marked "41", easy install 22 crankshaft degree parts, used in crate, ALL ZZ and older later model Suburban/pickup engines, 350/454, pick and match.

Start mechanical advance 100/150 rpm's OVER out of gear idle speed, limit mechanical advance rate limit to stop advancing between 2,700 and 3,000 rpms. This is by swapping springs.

For both distributor types, MODIFY THE VACUUM ADVANCE, IT HAS TOO MANY DEGREES OF TIMING TO WORK CORRECTLY. What is needed to be done is to stop down the pullo pin travel on the vacuum advance, with a simple metal stop screwed to the vacuum advance mounting bar. the distance the pin should travel should be limited to .086 inch, will deliver 8 crankshaft degrees, and an option would be .112 inch travel, 10 crankshaft degrees of vacuum advance travel. If you need pics of hosw to do this, I have them I can send, for either point or large cap HEI apps, just e/mail me at the address below, and I will send them to you, NO OBLIGATION.

When the vacuum advance has been modified, it can now be connected to the CORRECT sourcing, FULL MANIFOLD VACUUM, NOT PORTED VACUUM. This is via a hose port BELOW the throttle plates, in the bottom of the carb, on that one, in the DRIVER side of the front of the carb. This WILL bring the IDLE TIMING TO 20 (with 8) or, 22 (with 10) degrees timing, just what the engine wants.

For the vacuum advance stop pics, please send mail to me, and specify just which distributor we are working with, and I will send them to you: info@davessmallbodyheis.com

If you aren't able to do this stuff, I can, speak to me about sending your distributor, please.

[prostreetC-10]

That's some cool stuff on that sight Dave. Looks like you just became the "dizzy dude" on our site...... if you like. That's a serious need in those early cars. You may want to think about becoming a vendor on this site. Even though these trucks have gobs of dizzy room, many of us own earlier vehicles. Then again, if you are a mod on other sites, I'm sure you are way ahead of me. ;o)

[oldblue1968chevy]

thanks ALOT dave that'll be some help this weekend

[oldblue1968chevy]

I'll give it my best shot, worse come to worse I can send it to you.

Its an HEI distributor, what pictures do you need exactly? Thanks dave

[HEI451]

Only things I need to know for sure are:

That it IS in fact, a coil in cap, large daimeter HEI, to get you the correct picture package for the mods to the vacuum advance, end play and general stuff

And, your e/mail to the address I specified above, so I can add the pictures package to it for reply to you

This isn't hard to do, just have to ask the questions if you get stuck, raid the wrecking yards for the right center/weights, and spring it to work.

Easy deal. I came up with these mods fpor a company in So. Cal., some years ago, when I still lived there, because they installed a LOT of ZZ4 350 crate engines in the hot rods they built from scratch, LimeWorks Street Rod Repair, in Whittier. Come to find out, they work in just about every street driven stock, mild to somewhat moderate small and big block, crate and ZZ engines, and even motor homes like my neighbor's 454 pow3ered land schooner/barge across the street (1/4 mile away, actually.

For the dist on the 305E V6 I just installed into my 1964 Chevy C30 1 ton dually flatbed, it had a stock point dist in it, with the small Chevy II inline 6 engine cap, NO window, mechanical advance UNDER the points plate. Since its diameter is just small enough to cause trouble with a magnetic pickup and cap interference, I did what I always do, improvise.

I do a couple of conversions that are for the GM V6's, one is to build a full mechanical/vacuum advance distributor for the Chevy even fire 4.3 engines, to allow a carburetor to be run, removing the EFI, and, for other V6's, mostly, odd fire Buick/Jeep 3.8, 4.1, etc. The odd fire engines run a rotor with a trailing arm contactor, even fire cap, and the 4.3 is all V8, except for the cap, reluctor.

So, for my 305E, I took the V6 body and lathe'd the top off it, making a male plug at the top of the post. And, used a V8 small/big block dist body, top cut off and a female interference cut in it. When done, I sealed the register and receptacle area, pressed the two parts together, and set screwed them. This gave me a distributor that fit the V6 block like stock, and uses later overhead mechanical advance, larger diameter point type cap, and over the counter parts availability. The shaft was modified to fit the V6 gear, and off I went.

My V6 engine now has a remote coil, window cap HEI, with parts I can get mostly anywhere, and it FITS like a stock'er point distributor. At that time, I had not seen a later V6 distributor, but I understand I built what they are, with my mods, and didn't know it.

The last Rube Goldberg I did was a Joe Hunt magneto clone dist conversion. They run a GM HEI coil and PerTronix Ignitor in them, and for the $700 bucks they cost, fail the internals regularly. the owner has a 1950 Olds convertible street custom, with later 324 Olds engine, Man-A-Fre 4x2 manifold, 4 Moon Stromberg 97 two barrel clone throttle bodies, and Holley Annihilator EFI. He never did get the system to work right with the PerTronix, and, it died, as they all eventually do.

So, I fitted a GM 8 pin feedback module remote from the mag body, removed the internal coil, made the internal coil wire come out the bottom of the mag body, locked it out and installed the correct magnetic pickup. The coil wire is virtually not seen, runs through the firewall to the coil under the dash, fed by the 8 pin EFI module that triggers the computer timed MSD 6 Digital ignition box with rev limiter. The whole ignition curve and nozzle duty cycle is now done as a later model GM EFI would, just like inside your 200X (fill in the blank last number) GM vehicle. And, it still LOOKS like a Vertex Magneto.

It all boils down to just how creative, and insane one has to be to modify what others say can't be modified, like the people at Joe Hunt that told that fellow their clone dist couldn't be worked on by anyone but them, nor could it be changed away from THEIR internals, send it back to them, they were the ONLY people QUALIFIED to work on them. I have 4 more real Vertex mags from another friend that are all dead, one will find its way onto a blown, live Hilborn mechanical injected small block (4 porter on the street, MSD BTM box), two HEI's, one EFI-HEI.

The two sayings from above are more timely today, than ever before, live them both.

"Murphy lives in my shop and takes advantage of any opportunity he (she) can find."

(One of my grandmothers was a Murphy)

"To invent, you need a good imagination and a pile of junk. - Thomas Edison"

[oldblue1968chevy]

john68chevy@hotmail.com

I have a few GM weights

[oldblue1968chevy]

Found an extra set of stock weights, I have stock weights in the car now as well will get #'s tomorow hopefully

Here are the #'s for the stock weights I had extra..

106 for both weights

415 for the center weight

[oldblue1968chevy]

Just curious dave, do you have these weights EXTRA around your shop?

And what all GM vehicles would these weights be in (quite tedious pulling distributor after distributor apart looking for a small number) lol

[oldblue1968chevy]

My email is posted above, right now my email is down or something it wont let me sign in. Email pix info you think I need thanks

[oldblue1968chevy]

On my way to junkyard to look for weights (if I can, if I cant ya got some extra you'd send me...?) Looked on ebay with no luck.

375 and 41

[oldblue1968chevy]

Hei 1

[oldblue1968chevy]

Hei 2

hei 3

[oldblue1968chevy]

HEI 4

HEI 5

HEI 6


Im posting these for others to see as well.

Now im off to hopefully find some weights lol

[oldblue1968chevy]

No luck with the weights for certain #'s.

I looked in a 67-72 c 50 with hei (wrong #'s)

Looked in a 80 chevy k10 4x4 wrong #'s again.

[HEI451]

One MUST understand, the large diameter, coil in cap HEI's have a few different combos of weights/centers...437 different combinations. The 41/375 is KNOWN to give 21/22 crankshaft degrees of timing curve, nothing else does.

One other fact is notable:

In a point distributor, the center and weights only supply the mechanical advance curve degrees. The start and stop points are dictated by a pin/bushing to groove setup.

In the large cap HEI's, the combination of curve on the center and weight interface bar angle sets the three parameters, start, curve and stop points. THIS is why the large cap HEI's have so many varied and different centers and weights, and combos of each.

Usually, the trucks and SUV's from the late 1970's and early 1980'2 used the 41/375 parts.