Hi everyone.
Had a question about the 1968 Valiant. Were they available with the 273? I don't think I've ever seen one. I'd like to find a 68 Valiant with a 273 if they are available, but would a warmed up 6 be just as good? A have a Valiant now with a 6 and it's slow as a dog.
Thanks everyone.
Put a 2800 convertor on that slanty; That will wake her right up, and for low dollars. and
for the icing on the cake, add some mid-3 series gears, at least 3.23s, in the back.
More stall means less rear gear is required, at least in first gear. The quite wide 1-2 TorqueFlite split of 59%, means second gear will always be a bit of a stretch, no matter what rear gear is used. But, it can be minimized by making Second gear, your go-to gear..... which will make First-gear a bit of a rocket, but such is life, lol.
That's what I have done, and was never sorry.
Another thing I have done, is put a 340 in a 65 Wagon. Hyup that was a real blast.
but, just about any SBM will make your 68 a fun car. The bigger the engine-choice, the less stall and gear is required.
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This works both ways. For fuel economy, you can gear the V8s down to idle down the hiway; yet have better than slanty performance off the line.
To that end, I once put a 318/273 top end and cam, into a 340, with what I thought was funtastic results. I would totally do it again, but this time, with an overdrive trans, and big fat rear tires..
BTW
For best fuel-economy at low-rpm, there is a limit of how low an rpm you can go, and still get enough ignition timing, with the factory timing controls; at which point, instead of fuel-economy going up, it will go down.
There is no good reason to gear for 65=1400 rpm, if the combo makes best fuel mileage at 65= 2200rpm
Your personal ability to modify your distributor is what will make or break your quest, not rpm.
What I mean is that if your engine wants 56* of cruise-timing@ 2400rpm, you need to figure that out and how to make it happen. But if it wants 40* at 1600, you gotta make that happen too.
The 225 has a modest bore size , and a generous stroke, perfect candidates for generating good fuel-economy numbers, with a reasonable amount of take-off torque. It was a great idea, but from the factory, it always lacked decent cylinder pressure to pull it off.
I twice, pumped the Scr up on my 225s to 9.5, and it was well worth the change. Of course I also modified the distributors, and changed the gearing, and re-stalled them. On one combo, I installed a 2.45 rear gear, and a lock-up 904. Oh yeah, that one was a lil soft on the get-go, but she was a hi-way car, and a fuel-sipper. The other got the 2800 and 3.23s. It still did fairly well on the hiway, but it was a Second-gear sweetheart.
The best way that I have found, to get the timing really close, is with a stand-alone, dash-mounted, timing control. Mine has a range of 15*.
I modify my distributors to what I suppose will work, bolt it in, and roadtest. Yes it may take all summer to dial it in with multiple in-outs and it really is a PITA on slantys. But the end-result has always been so worth it.
BTW-2
I would NOT be afraid of installing a 360LA.
But, I would first pump up the Scr with a tight-Q. Then I would regear it with a 2.20/2.45 rearend, and give it a lock-up trans...... and fix the daymn timing. and then I would stall it up a lil if necessary.
These 360s got a bad rap in the economy department, but really the thing that killed it for them was the low Scr and open-chamber heads. Fix those two, and I have gotten fantastic fuel economy out of them. Yes it will cost a few thousand dollars to make it happen. But in the end, it will rival your EFI car. Over the life of the vehicle, you will get the cost of the engine mods back, many times over, in the fuel savings alone. Drive it 12,000 miles a year, and in two or at most three years, you may already have broken even.
Going up a few gear sizes, will flip the coin to performance, with no other changes in your 68Valiant which is a lightweight car.
And from there, you can easily take it to warrior status with bolt-ons. But it all begins with the Hi-compression/tight-Q design.
And yes, at this early stage, you can bias the combo to one side or the other, performance versus economy, and even to do both! a thing which is gonna be more difficult with a shorter stroke SBM.
For me, 360s are like potatoes at suppertime. You can dress them up in a myriad of ways, and potatoes always taste great. You can even pretty them up with add-ons, and I will never tell my wife; you know darlin' I think I woulda liked rice today; NEVER!
