An Economaster on a 350?????

[spdrcr29]

Looking for a new carb, was settled on a reman. Q-jet from the local parts depot until I found a rebuilt Holley Economaster 450cfm for sale.

My motor is stock, 'cept the HEI (soon) and a cotton gauze air filter. Ram horns and 2.25 exhaust. I'm not planning on drag racing the truck, but the seller says he's used the same carbs on tow vehicles with 7500+ lbs behind 'em without problem.

Did a google search on CFM requirements, and it said 450 was big enuff.....
80% V.E. and 4700 rpm redline used for calculations.


Soooooooo????????

Somebody talk to me and make up my mind here!

[uncle]

I had one on a 350 in a 72 Vette once. Still had plenty of power and got 18 mpg. This however was a Vette, not a truck (weight difference).

[spdrcr29]

Originally Posted by uncle

I had one on a 350 in a 72 Vette once. Still had plenty of power and got 18 mpg. This however was a Vette, not a truck (weight difference).

Yeah, I've heard good things about the carbs on cars.
Couldn't find the curb weight for a LWB 1971, but found it for 1970.
3737 lbs, according to the 1970 truck page.....
3305 lbs for the 1972 Vette according to the Idaho Corvette page.
432 lbs means the car weight is 12% less than the truck.......

Scrubbing 12 percent off 18mpg still yields over 15mpg, even though this measurement is highly innaccurate due to differences in gearing, aerodynamics, etc...... 15-16 mpg would be outstanding, and I'm not gonna be driving like a maniac. Just concerned about towing my 16 foot boat to the lake on the weekends.

Anybody else have any input?

[68C15]

for the long term I think you would be happiest with the Q-jet. I have one on my truck with a meduim cammed 355 and I get 14 - 16 MPG.

this may be of some interest. I feel the same way even after having tune a butt-load of Holleys.
http://67-72chevytrucks.com/vboard/s...d.php?t=201099

[qksilver]

The Q-jet would be a better choice, look for somebody to rebuild it . The local what ever , when they rebuild they don't rebush the throttle shafts. That's why most parts store rebuilds stink

[spdrcr29]

Originally Posted by qksilver

The Q-jet would be a better choice, look for somebody to rebuild it . The local what ever , when they rebuild they don't rebush the throttle shafts. That's why most parts store rebuilds stink

Ok, so I'm getting that the Q-Jet is the favorite, but do any of the major rebuilders (Holley, Champion, etc) rebush the notorious throttle shaft??? I called a couple auto repair shops about a rebuild and they acted like I was asking for a kidney...
"We, uh, don't, uh, deal with a lotta carburetors, everything is fuel injection these days" NO ****???? I musta overslept!
Hence the Auto Zone/Advance/Checker "reman"s are the way I'm leaning now.
(No drill press in my garage to do the rebush)
Any good news about these? I saw one good post in the thread listed above, but that may have been because it was a fresh install.

I guess I could slap a cheapy on and send my n/m original out for a refresh.

[pritch]

Back in about '82 or so I put one of those Holley Economasters on a '67 longbed w/ a 350. I don't remember what CFM, if there were others besides the 450, but I was happy with it. It got better milage than with the wore-out Q-jet that it replaced. HOWEVER, I later used that carb on a blazer-same motor as the truck-and it sucked out loud! Apparently the bowl holds less gas, or the needle valve shuts it off to soon or something, but it won't let you go up a hill that is very steep. I found this out hard way, getting down into a place that was steep both ways out. This is not a good carb for any off-roading!

[spdrcr29]

Thanks, pritch,
Do you remember if it helped with any more low end grunt in the P/U. My ride is going on 20 inch rims and is strictly pavement. Plus, I'm in lower Michigan. We can't find a hill here.

[pritch]

It seems like overall,the performance was fine. I never wanted for power. It was such an improvement over what I had that I was happy. The only issue I had was off-roading. For a street truck, with these gas prices, I'd do it again.