Rochester FI combination of parts
 

OK, in digging back through some old threads related to this topic on NCRS site I have determined that an early 1707380 unit COULD have had a 63 style air meter.

The next question is whether or not this unit could have also originally had a 1111063 distributor.

To recap, I have a 1707380 unit, serial number #1250, which has a 63 style air meter and a 1111063 distributor.

I know this combination of parts puts us in a narrow production window of sometime around late Nov - Dec of 1963.

The intake is dated 10.1.63. The distributor is dated 3 L 12 (Nov 12, 1963).

So, how likely / possible is it that this combination of parts is original to each other and a specific car?

Check VH's.

Yes, it is possible that the combination of parts could have originally been put together by Rochester/GM. But it may be very difficult, if not impossible, to verify if they were originally installed on the same car.

OK, John DeGregory has confirmed (in an old NCRS post) that early 7380 units (Nov, early Dec 63) could have used 63 (7375 / 7375R) air meters.

There was a short period of time in late 1963 when both 7375R and 7380 units were used at the same time, according to John D.

My question now is if it is possible that a 1111063 distributor could also have been used with an early 7380 unit.

I think yes, given the fact that 7375R and 7380 units were being installed at the same time (a small period of overlap), but no way to confirm that.

Your 300 hp engine may not like the fast advance of that distributor.

I was thinking about that.

I suspect that the distributor will need to be build to 300hp specifications, with maybe a bit of tweaking beyond that.

If it causes detonation problems, I'd be thinking about swapping out the vacuum advance with your 300 distributor. But, you may be okay.

All kinds of combinations and parts swaps are possible with these old injectors. It's been done for many years (over 60yrs) by many people (some did, and some did not know what they were doing) to many different FI units.
The unit on the SB400 in my 56 is a true hybrid which is literally composed of parts from 57 to 65 units, plus a few of my own modifications.
Originally, I used a 62 mechanical advance FI dist and I always felt that overall performance would be better with a vacuum advance dist. About 25yrs ago, I replaced the 62 dist with a 65 (has vac adv) dist. The difference was a night and day improvement in perf and idle and cruise operation.
Thus, after many years of trial and error, I finally put together an FI unit which does almost everything quite well. It's very dependable, Starts, idles, runs and and works great at wide open throttle with virtually ZERO issues.

I am sort of figuring on swapping out the weights, springs, and vacuum advance for the 300 hp parts.

The only think I am not sure about is the football at the top of the distributor shaft.

I will compare the two (the 375hp and the 300 hp) and see how different they really are.

Absolutely correct, but as far as I can tell, this FI unit is a matched set of parts for a late Nov or Dec 63 7380 unit. The only question still outstanding is the 063 distributor. The time frame of the use of the 063 is correct, but I don't know that an 063 has ever been used with a 7380 unit.

I would say the components are likely original to each other based on the following

The earliest 070 build date i have recorded is 3M26 there could be an early build date.

The latest 063 build date I have recorded is 3L12, there could be an older build date

080 units with 63 air meters I have recorded SN 1217, 1233, 1390

080 units with 64-65 air meter SN 1442,1452, 1486

I have recorded these 6810 adapter plate cast dates 9-17-63, 9-19-63, 10-1-63,11-12-63, 11-13-63, 11-14-63, 12-28-63

080 Units sold with 063 dist SN 1217(3K22), 1281(3L12), 1442(3K12), 1486(3K22)

All data taken from eBay listings over the years

Pretty simple in my mind.

Keep the things that came together with this FI unit for if and when you decide to sell it.

If I were going to install it on my car with and original 300 h.p. distributor I would evaluate the condition of the distributor that came with the FI unit and if it needed work ($) I would probably just change the vacuum advance and springs in my 300 h.p. distributor If the FI distributor is in good condition I would ue it.

The '66-'67 300 HP spark advance map is about ideal other than needing lighter springs to bring the full 30 deg. centrifugal in by no later than about 3500 instead of the OE 5000, and a 300 HP cam with manual transmission needs a 15" B22 VAC or 12" B26 with an auto trans. The OE distributor with the 380 FI unit is 24 @ 2350, and the 8" 236 16 VAC, but this map is too aggressive for a 300 HP cam, especially is the CR is 10 or more.

Don't worry about the football, but you'll need to grind the slot in the cam assy. to increase the centrifugal from 24 to 30. Eight to ten initial will yield total WOT advance of 38-40 and total idle advance will be 24 to 26, which is ideal for a 300 HP or McCagh Special cam. If the air meter is a '63, it's set up for ported vacuum advance, so you need to convert this to full time.

Duke

Thanks Duke.

I "sort of" follow this, but this is outside of my area of experience. Can you be more specific when you say "grind a slot in the cam assy, to increase the centrifical from 24 to 30"?

I believe that the 63 air meter is original to this unit, as well as the 063 distributor, but I am wondering if, for my specific application, I would be better off with a 64-65 air meter and an 070 distributor.

I would not get rid of the current parts, just get additional parts to replace them.

Thanks.

Ed

I have to use an FI distributor, The FI distributor has the drive mechanism for the pump in the fuel meter. I do not have to use THIS FI distributor.

Ed,

Don't sweat the air meter. Use what you have.

The difference between a '63 air meter and the '64 - '65 air meters is simply the presence of a pipe-threaded port on the '63 air meter to which you could attach a vacuum line for ported vacuum. On your FI unit, that port is present but plugged.

Don't give it another thought.

Jim

Thanks Duke.

I "sort of" follow this, but this is outside of my area of experience. Can you be more specific when you say "grind a slot in the cam assy, to increase the centrifical from 24 to 30"?

Also, what exactly does this statement mean "If the air meter is a '63, it's set up for ported vacuum advance, so you need to convert this to full time."

The vacuum advance canister on the distributor connects to a fitting that is on the upper rear right side of the plenum (see picture below)

I believe that the 63 air meter is original to this unit, as well as the 063 distributor, but I am wondering if, for my specific application, I would be better off with a 64-65 air meter and an 070 distributor.

I would not get rid of the current parts, just get additional parts to replace them.

Thanks.

Ed

https://cimg2.ibsrv.net/gimg/www.cor...b5826f1d50.jpg

Agreed, use the air meter you have. As to the distributor do as Duke recommends or change the main shaft to the 070, spendy, time consuming, and a bit extreme. My memory says there is one other very, very small difference in the air meters pertaining to the stop pin for the choke butterfly. The 65 shop manual supplement states "choke changes to improve engine warm-up performance." It does not say what those changes were but I recall Chevy/Rochester sold a choke modification kit with instructions to relocate the stop pin on the earlier 63-64 units to provide an additional 10 degree closure of the choke butterfly. That modification would have been a pain to do in the field. I bought one of those kits to obtain a missing choke piston and cover, cost was less than $5.

That means just plug the vacuum port in the air meter and forget it. Tap your vacuum advance where you indicated.

The 070 distributor has advance map just like the one you have. The '63 022 would be closer to what you need. I wouldn't do anything until you try the one you have.

I am wondering if I can try an FI distributor with the carburetor and intake manifold currently on the car.

I am thinking about dialing in an FI distributor before I try it on the FI unit.

I see two options here:

1. Get another FI distributor and try it. Apparently the 022 is closest to what I need for a 300 hp engine.
2. Modify the 063 distributor that I have to meet the needs of my 64 300 hp engine. I do not want to do permanent changes to any part of the original distributor, but I can make changes to other parts that can be replaced in the distributor.

It seems like Fi distributors are expensive, but perhaps I can get another distributor main shaft for the 063 that will work better for my application. That, along with changed weights, springs, and vacuum advance canisters, might get me where I need to be.