Am I missing something, or would this actually have a chance of working?
IF you're actually a newbie at slant sixes, there may be pertinent facts of which you may not be aware, that miight alter you course of action regarding engine mods.
The main fact is, that the 225, (and to a lesser extent, the 198-size slant sixes,) have a big problem trying to breathe through the original cylinder head since it was only designed for a 170 cubic-inch motor. There are no easily-available alternatives (NO aftermarket cylinder heads,) beyond adding larger valves and porting, which does help, but isn't going to make two horsepower-per-cubic inch possible, normally-aspirated.
The problem exists because the managment that ordered the original engineering on that motor wanted a short engine (front-to-rear) and that design factor dictated small cylinders. Small bore cylinders don't leave room for very big valves, and since the ports were designed for a 170, and were never changed, getting enough air through there, to feed an engine 35-percent larger, even with a ported head, is still a problem.
You can add the nicest-appearing, best-flowing intake system to that head, imaginable, and pick up some horsepower yes, but the head is always going to be the flow-bottleneck that stifles performance.
It is possible to make enough power normally-aspirated, to have a lot of fun with an A-body, using the usual, everyday modifications like hi-compression pistons, a 4-bbl carb, (or, in your case) Fuel Injection, headers, and a higher-lift, longer duration cam. One FABO member has his /6 Valiant running low 11s with no power adder. But it's been treated to a full-race buildup, probably isn't very streetable, and is installed in a severly-lightened body (2,350 pounds, I think.)
There's another FABO member who has a 1970 Dart that has a milder engine, but still pretty well "built," that better exemplifies what most folks would more likely do, but his Dart runs very low 14's... and maybe high 13's by now.
Fuel injection isn't going to change that, appreciably.
You can add nitrous to any engine and pick up power on demand. But nitrous is an ongoing expense and some don't like the prospect of running out at the wrong time...
The other alternative is forced induction; supercharging or turbocharging.
Because the slant six was originaly an aluminum engine (60,000 aluminum ones were built before Ma pulled the plug,) the
construction parameters of the leaning tower of power are exceedingly strong. All the early ones had forged cranks, and the changeover to cast iron as a block-construction materisl was done without doing much re-design of the main bearing webs, and other strength-giving elements of the block. It's almost built like a Diesel. STOUT!
That fact makes it possible to add large amounts of cylinder pressure through forced induction, to high boost levels that produce prodigious amounts of power by autilizing forged piston and rods (easily available) and O-ringing the block.
Two such examples have been built by members of tis board and two others are being built as we speak. The two that have already been run have provided us with videos that demonstrate that they make in the neighborhood of 500 horsepower, each. That's with a slight overbore on a 225, and a ported head. One 4-bbl carb is used. They don't need rpm to do this: 5,500 rpm is the redline for both of them.
I am not suggesting that many people want to get 500 horsepower out of one of these engines, but the prospect of a 300 horsepower slant six with a turbo should be a not-too-difficult exercise in hop-up, nor very expensive.
Going that route might not be any more expensive or difficult than build the FI engine, which could be a chore to get 300 horsepower out of.
It's just food for thought; Good luck with whatever you decide!! Slants are fun, either way! :cheers:
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