Hey guys,

a co-worker wants to install a 4bbl carb onto his stock 250 6 cyl engine.
He has a Clifford intake manifold.

Just would like some feedback on what you guys like for todays market of carbs, 4 bbl carb that is.
Around 400 CFM he is looking into.
For headers, I told him to use Tom Langdon cast iron headers.

I only have info for the carbs I have used & that was many years ago.

Thanks guys.

MBHD

I'd say the Holley list # 8007 390 cfm with vac secondaries. On a heated intake.

His Clifford does not have heat.

I never had a heated intake on my Offy of Clifford & they worked fine IMO.

The damm header is right under the intake manifold & heats up the intake manifold pretty damm hot.
We are in So-Cal so it does not get that cold here.
His ride, a 67 Elky, & it's not a daily driver, for that duty, a Honda Civic.

What is the carb you have on the 65 Wagon? Model #?

MBHD

He runs a progressive 2 BBL on the wagon not a 4 BBL.

Thx, I would like to know what the model # of that 2 BBL if possible.

MBHD

It is a Holley 2305 series carb. list 80095.
They are hard to find. It does hold back this 250 in the wagon. It is 500 cfm. For a mild engine, it would be the perfect carb.

HP limit will probably be about 225-240 hp.

The heated intake will work in all climates. Keeps fuel from puddling under carb, like everytime the accelerator pump squirts. Promotes better fuel atomization, crisper running engine, better efficiency.

If mileage means ECONOMY (ie including the price of the carb) I'd say the winner is the 2 carbs that you get the best deal on (one for a spare). In all my testing on the 250-pg-308 car, unheated Clifford, it was really close between the Holley 390cfm and 450cfm, the Carterbrock 600-625cfm, and the Autolite 4100 440-500cfm carbs. The Carterbrocks surprised me as they were way too big but ran within <.1 and <.5mph of the Holley's best run. I wonder if the little 500cfm Carterbrock would've won but didnt have one to include.

Overall for our mild weather as U say, doesnt make a big diff. My go-to carb was/is the 390 Holley, couldnt go too wrong there. But for everyday use, I run an Autolite 4100 (eg right now). Advantage to those is you can always resell em to the Galaxie/Mustang folks.

So it really comes down to the best deal U can get on a good runner. Good to have a spare anyway.

Thanks Tlowe & DeuceCoupe,

DeuceCoupe, between the Holley 390 & 450, the 390 worked a hair better?
How about driveability? Both about the same?

I ran on my 250 6 cyl an old Carter 400 CFM AFB, 1965 273 V-8 era & it ran really good w/that. I did do a little tweaking to it though.

Thanks

MBHD

A Quadra-jet set for a 4.3 Chevy works very well on a 250.

Do you happen to know what size metering rods & jets needed for a 250 engine?

Thanks

MBHD

a good start would be the jets from a pre-smog era engine: #71 prim jets plus #45 metering rods (rods could vary a thou or so either way) as a check look into what the '66/'67 ohc pontiacs used (not the '68 & later as they were into the smog era and as we all know leaner and needed all kinds of crutches such as heated air cleaners etc).

What size primary jets and rods did you use with the 273 inch Mopar carb?

PNC,Quote:
"What size primary jets and rods did you use with the 273 inch Mopar carb? "

It has been so long since I used that carb I cannot remember.

I had bought a Carter carb kit w/metering rods & jets & springs for it & I had to mod the springs (make them lighter tension) because w/the cams I was using had quite a bit of overlap & had low vacuum. You could actually here the metering pistons jumping up & down while idleing.

I also removed some weight material off of the secondaries so they would come in sooner on the same 400 CFM Carter AFB.
That was a good little carb I.M.O.

I think there was a website stating what size jets & metering rods came on the Sprint six engines?
Anyone got a link?

Thanks.


MBHD

Look up the specs for a 1985 chev Astro van with a 4.3 they ran a Q jet then went to TB in 86

Hank,
Too close to call btwn the 390H and 450H in Gtech times, they each "won" a couple times. So again I'd say, whichever one U get a good deal on is the winner. Driveability, 390H seemed a bit snappier but that was just a "Feel". Just too close to call.