Holley 350 cfm 2 barrel, replace the Solex

[MunichTaxi]

I found a website that sells the adapter plates for the Holley 350 cfm 2 barrel carburetor # 7448, to a Q-jet manifold.

http://www.castheads.com/carb_adapters.php

Will this work on the Mercedes M110 intake? I assume I may have to re-jet the card?

And, would the Mercedes steel gas line then be replaced with an American threaded gas line to the next available rubber gas line union? (probably answered my own question)

Does anyone have a link for the Holley/Solex conversion? Thanks

[alabbasi]

The only people that I know who do this conversion are Jam Engineering.


Jam Engineering

[Mike D]

You don't need anything that expensive or fancy. In fact, that adapter probably won't work due to the linkage bracket mounted directly behind the 4A1.

Try this. Go to any Autozoo, CSK, NAPA, Carquest and get a standard 4BBL to 2 BBL adapter

Use the fiber spacer as a template for the mounting holes. The front holes will line up but you'll need to machine the rear holes.

Here's how it looks machined and here is a bottom view with a 2 BBL Autolite carb mounted.

[Mike D]

Or try this! A 4BBL Quadrajet from any '70's Detroit iron. This one is from a 1976 Pontiac GrandPrix 400 c.i. I machined the rear mounting holes using the fiber spacer, removed and plugged the rear vacuum port on the Q-jet and used Allen-head bolts on the rear due to clearance issues.

I re-located the return valve and used an electric fuel pump..


You'll need to plug the choke hot water lines or plug them at the manifold. You need to keep as much of the stock accellerator linkage as possible since it affects the automatic transmission shifting. Don't look at my disconnected heater core. One of these days I'll fix it. Not a big priority here in Tucson..

A short chrome air filter to top it off. Do not use the fancy-dancy wing nut they provide with the kit. Turn the top of the aircleaner upside down so the dish is down. Ask that ripple in my hood why.

[t walgamuth]

i did a Q jet conversion to a 74 bmw 3.0 liter years ago. probably no harder than doing the 2 barrell.

i had three different carbs on there before i was satisfied. i ended up with a all manual carb. manual choke, manual secondary operation. i used the jet metering rods from a 67 pontiac sprint (the straight six). i also bought a qjet haynes book for reference. (i am not sure it was haynes.)

you had to be careful not to open up the secondaries under 3000 rpm but when you opened them up she would scream all the way to the redline!

it was a big improvment over the original soles POS which i rebuilt at least five times before resorting to this.

the thing i had to jury rig the most was the throttle linkage.

if you do this feel free to pm me. i still have the qjet book.

tom w

[MunichTaxi]

I am new at this conversion, and all your answers/pictures are very helpful.
Especially the one for the generic adapter plate.

I'm hesitant to replace the Solex with a 4 bbl for 2 reasons:
1. Assumed better fuel mileage with a 2 bbl carb
2. The trial-and-error of re-jetting a 4 bbl for a 2.8L engine.
3. I don't mind the $$ expense for the new 2 bbl carb,
since the purchase price of the vehicle was low.

I guess the real question is if the Holley 350 cfm 2bbl is correctly sized for the 2.8L, or if an even smaller 2 bbl would be correct.?

[MunichTaxi]

CARB CFM = Cubic Inches X RPMs---X ----Volumetric Efficiecy
-----------------divided by 3456

Looks like the 350 cfm 2 bbl is not correct.
Hmmm..., the 4 bbl looks better.

[t walgamuth]

the quadrajet is known to supply good economy if you stay out of the secondaries.

an engine doesn't know how big the carb is. the carb doesn't know how big the engine is. the air passing through the carb is suppllied with enough fuel to make the proper 14 or so to one ratio of air to fuel.

so the size of the carb is not really much of a factor except that with a big one you are tempted to run the car harder which uses fuel.

if i were doing a q jet conversion i would use a edelbrock replica q jet.

if i could afford it. back then though i got a cheap one from the old junkyard that is long gone and replaced by apartments now.

tom w

[MunichTaxi]

Do I need a carb with a Auto trasmission kick-down lever?

[t walgamuth]

i think the lever attaches to the throttle linkage doesn't it?

tom w

[MunichTaxi]

I will definitly explore the edelbrock replica q jet.

[MunichTaxi]

This carb is listed as THUNDER SERIES AVS:

Mild perf. street (small CID) single-quad 500 cfm Adj. elocity 225 - 327 cid
Up to 220°

Mild perf. street (small CID) dual-quad 500 cfm Adj. Velocity 225 - 327 cid Up to 220° Dual plane 1803*/1804*


And the whole list:

THUNDER SERIES AVS CARBURETORS
Mild perf. street (small CID) single-quad 500 cfm Adj. Velocity 225 - 327 cid Up to 220° Dual plane 1801*/1802* 18014*/18024* 1486 (F)
Mild perf. street (small CID) dual-quad 500 cfm Adj. Velocity 225 - 327 cid Up to 220° Dual plane 1803*/1804* 18034*/18044* 1486 (C,D)
Moderate high-performance street 650 cfm Adj. Velocity 302 - 400+ cid Up to 220° Dual plane 1805*/1806* 18054*/18064* 1840 (E)
Off-road high-performance 650 cfm Adj. Velocity 283 - 460 cid Up to 220° Dual plane 1825*/1826* 18254*/18264* 1842
High-performance street/light strip 800 cfm Adj. Velocity 350 - 502 cid Up to 250° Dual plane & 1812*/1813* 18124*/18134* 1841
small single plane

PERFORMER SERIES CARBURETORS
Stock replacement/mild perf. street. 600 cfm Velocity 305 - 350 cid Up to 200° Dual plane 1400 N/A N/A
Calibrated for economy, 50-state
legal on ’80 and prior GM only
Mild perf. street small CID & dual-quad 500 cfm Velocity 225 - 327 cid Up to 220° Dual plane 1403*/1404* N/A 1486 (C)
Moderate street high performance, 600 cfm Velocity 302 - 400+ cid Up to 220° Dual plane 1405* 14054* 1479
street and towing
Mild perf. street, calibrated for economy 600 cfm Velocity 302 - 400+ cid Up to 220° Dual plane 1406* 14064* 1487
High-performance street (small CID), 750 cfm Velocity 350 - 502 cid Up to 230° Dual plane & 1407* N/A 1480
Moderate high-perf. (big CID), towing small single plane
Mild performance street, towing, 750 cfm Velocity 350 - 502 cid Up to 230° Dual plane 1411* N/A 1489
calibrated for economy w/performance
High-performance street/light strip 800 cfm Velocity 350 - 502 cid Up to 250° Dual plane & 1412*/1413* N/A 1480
small single plane
Dual-Quad Small-Block Mild/High-Perf 500 cfm Velocity 302 - 400+ cid Up to 220° Dual Quad 1403*/1404* N/A N/A
Dual-Quad Big-Block Mild/High-Perf 600 cfm Velocity 400 - 502 cid Up to 250° Dual Quad 1405* 14054* N/A
PERFORMER SERIES MARINE CARBURETORS
Mild marine performance 600 cfm Velocity 302 - 400 cid Up to 220° Dual plane 1409* N/A 1488 (A)
Mild marine performance 750 cfm Velocity 400 - 502 cid Up to 250° Dual plane & 1410* N/A 1480
small single plane
CARBURETOR APPLICATION GUIDELINES
(A) Use calibration kit #1485 on 4.3L 90° V6
with #2111 & #2114 manifold
(B) Adapter #2696 required for OEM spread-bore intakes
(C) Calibration required for single quad applications only
(D) For dual-quad applications from 302-400+ cid
(E) For dual-quad applications from 396-502+ cid
(F) Calibrated for single carb applications only

[t walgamuth]

the q jet or a replica will bolt up and match the manifold with just two of the bolt holes requiring enlarging.

a square pattern or one with four throats about equal will require an adapter.

the rule of thumb guidelines will tell you that a q jet is too big, but the guidelines are for engines that turn maybe 4500 rpm. a smaller motor turning 6500 rpm will flow just as much air per minute.

note that the 110 came with the same sized carb as a q jet.

a smaller carb will work fine too but will limit upper rpm power.

tom w

[Mike D]

Just swing by a junkyard and get a Q-jet carb. $20, pick up a rebuild kit from any Auto parts store $20.

I really don't think you want to drop $300 for a Edelbrock. Before you go that route, spend the same amount on a Throttle body injection system with a Megasquirt controller.

The transmission shifting is controlled by the linkage going across the valve cover and the electric kick-down solenoid.

If you do get an spreadbore Edelbrock (replacement Quadrajet), get a manual actuated secondaries unit. You won't have clearance for the vacuum actuator.

All Q-jets were 650 CFM (some claimed to be 700 but they weren't). The only difference between one used on an in-line 6 cylinder Pontiac and a huge rip-snorting 396 C.I. Chevelle was jetting, primary and secondary metering rods.
They would all flow a MAXIMUM of 650 CFM. Fuel is transferred by air flow so the size of the engine was no matter.

[MunichTaxi]

I attached a link for the $239.99 Performer carb at Parts America. I was told to print the page, an any Schucks dealer will honor the price.
I am planning to e-mail Edelbrock, and hopefully they will recommend a metering rod/jet kit for the 2.8L. (I don't plan to run the vehicle at 6,000 rpm's)

The Thunder series uses springs on the needle and seats for the 4WD crowd.
It is more expensive the the Performer.

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=EDB&MfrPartNumber=1404&CategoryCode=3338A