Stock '69 318, t-quad vs q-jet vs holley vs edelbrock?
Hi all,
Just got a '69 dart with a 318. New to this engine and mopars in general. It is a completely unmolested engine, stock two barrel of course. After I get some headers and dual exhaust on it, I plan on doing a 4 barrel swap. In terms of intake, I could go for something spread bore to run a t-quad or q-jet, but is this the right way to go? I could also try to find a square bore intake and run an edelbrock avs2 or a holley vac secondary...
The t-quad seems really appealing given the stories of great mileage and unparalleled airflow for the price but is it more of a hassle?
Thanks guys
IMO
the changes that you are contemplating, at zero mph, will not help performance at all. In fact, when you install a spreadbore carb, you are likely to lose performance until the secondaries open.
The torque peak of your stock 318engine should occur at or near 3000rpm, perhaps a little sooner with the 2bbl.
Which will then occur, if your car has the typical 2.76 gears, at close to 28/30 mph. Horsepower does not increase all at once, but starts at 1hp, then 2 then 3 and so on, increasing with rpm. If your changes make 15/20 hp, this won't happen until about 4400 rpm. When you install the 4bbl, if the tires do not spin, this will be at or near 40 mph.
In other words, you can expect the power to BEGIN at 28/30 and peak at 40, in first gear, with a stock convertor, and 2.76 gearing.
I bet that is NOT what you're expecting.
I bet, you want performance, right from the take off.
If that is true, then yur gonna need a higher than stock stall, and performance rear gears, and I recommend a double-pumper carb.
If it was mine;
Since I know this is what I would want from my combo, and
since I know that your combo will need the higher stall and gears anyway,
I would just do that first, and save myself the disappointment.
Both of these work together, starting at zero mph, and
because the tires will now spin, the double pumper will make it easier to control the power, without surprises. Expect to have to install the biggest tires that fit and you will need a Limited Slip.
If you do not go this route,
that's fine, but at least do this;
With the current combo, and with fresh oil in her, time your first gear performance from zero mph to whatever speed gets you ~4400rpm. Run the test 3 times and record the best time. This will be your minimum target with any and all changes. If the tires spin, the test is invalid, start again with less throttle.
Then, after whatever change you make, run the test again and record the results.
In conclusion therefore,
I recommend,
both a higher stall, AND gears in the range of 3.91s plus/minus one gear size, plus the Limited Slip and big-boy tires.
I like a good rowdy Dirt-Jerker2800 TC.
When you do the gears, you will need a new speed-o gear.
When you do the hi-stall, you might as well install a shift kit; and because I can, I would also rebuild the trans.
When you install the 4bbl, you will want to upgrade the trans anyway, and this will want a new governor arrangement; and she will want a free-flowing dual exhaust.
If you contemplate a cam-swap, to anything with over 40degrees of overlap, she will want headers. I would not stay with the 318 logs , after the 4bl goes on.
Having done these kinds of swaps since the 70's,
these are my opinions.
You will not hurt my feelings, if you start with the 4bbl. In fact, if you post your time-trials, you can prove me wrong! ; and I'm Ok with that too; all I ask is that you be accurate and honest.
