I have had my '69 400 4-spd 'vert for about two months now and am trying to get a few of the bugs out. I have had some trouble with my Holly carb (H-1850, 600 CFM) with manual choke, mostly hard cold starting and heavy carbon deposit out of the exhaust once it does start. I spoke to the owner of a local garage and he recommends putting in the original Rochester carb with electric choke, he added that the Rochester will waste less gas as well. I am considering the change to the Rochester. Any thoughts either way?
You'll definitely feel the difference if you upgrade to a 750 cfm carb, whether it be the Holley #3310 with vacuum secondaries or the Edelbrock Performer #1411 with mechanical secondaries and electric choke. The Edelbrock lists for around $282.00 and the Holley for around $302.00, including the electric choke, and are readily available at Jeg's or Summit. Keep in mind, both of these carb's are square bore. The Rochester Q-Jet's range in prices from $350.00 to $390.00 which are 750 cfm, and I believe they are spread bore's.
I'm currently running the Edelbrock Performer, 750 cfm carb,#1407 along with the optional electric choke. This is an excellent carb which is easily rebuildable and tuneable.
1) get the carb you or someone you know can work on 2) Holley will waste more gas than the Q-Jet 3) I run a Holley because my buddy is good at working on them , see no 1, LOL) 4) a Holley 750 is way to big for a 400 imho, you`re wasting gas... a 650 is 'just right' , if its a Holley... I now run a holley 650 on my 400...
just a side note..I once had a Holley 650 on my Ford 302 in a Healey replica ( 1950 lbs fiberglass car), I got 12 mpg...changed to a 1850, I got 19 mpg and car was quicker! Bigger is not always better...the air wont be able to mix with all that gas...
I second Bjorn. The Q-jet is best, but if you have a buddy who knows his way around whatever you can get and you can get it cheap, go for it. I will eventaully be running a q-jet but for right now have a 600 cfm holley and it works fine 'cuz my buddy knows how to set it up.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> holley is junk unless you run the car on the 1/4 mile track exclusivly </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">hmmmmm....not what the people say that ride with me or drive behind.....
Read and then re-read what Bjorn said about "get the carb you or someone else can work on". No aftermarket carburetor is perfect out of the box (although the Carter TQ comes close).
The brand of carburetor is less important than the design (square-bore or spread-bore). There is an excellent reason that ALL US manufacturers started using the more expensive spread-bore designs on virtually ALL production cars after the design came out; and that is because the spread-bore is best for the street.
As a general rule, the spread-bore is going to have much smoother driveability, and use less gas than the square-bore.
Remember that Pontiac used the Q-jet (spread-bore) on engines from the 6 cylinder Sprint to the RA IV.
Now, if you happen to be professionally road racing, the square bore is easier to modify for this purpose; probably also somewhat easier to modify for circle track racing. Drag racing no benefit (assuming equal CFM) either way.
Parts are probably more readily available LOCALLY for the Holleys. Mail order, probably little difference.
Jon.
Good carburetion is fuelish hot air Owner, The Carburetor Shop LLC
Hello and thanks for all the input! I did go back and search the tech archives (great tool). Given the advice and my use pattern (not racing, more reliable driving). I will plan to replace the Holley with the Q-jet. Thanks again, Mark
