I think the pistons are about .080 down in the hole so that's 15.74cc, add 6.2 for .028 gaskets, and 63cc for the Eddies, and that comes to ~85cc and so the Scr maths to ~8.7..
IMO, this is not enough improvement to warrant the expense. Better to stick to closed chamber iron heads, with smaller chambers like the 58cc ones; which could maybe get your total chamber volume down to 80cc, and thus 9.15 Scr.
That's probably a lil high for the factory cam and the no squish chamber, but if you could keep it out of detonation would be just the ticket..
The big thing with those cars is the crappy hi-way gears in the back, and the low-stall TCs.
The convertor starts the car off at a low-torque place on the curve, and the rear gears keep it there, seems like forever.
Those would be my first targets for performance improvements.
Think of it this way;
on the start line at zero mph, what can you expect from headers and a 4bbl?
Say you have an 1800 stall TC. You punch it and the Rs jump to 1800...... at which point your teener in factory trim has um say a max available , foot-to-floor, 190 ftlbs (65 hp) . The 4bbl will not open at 1800,and even if it did, the 2bbl can handle the engines air requirement at 65hp.The headers are not yet on-line. Yeah they are better than the factory logs, but lets be generous and say 5% or 3hp. So you are up to 68hp tops, foot in the carb..... ; remember this number;plus 3%.
Some guys will jump the headers to 10%, so what; that's still only 71.5hp@1800rpm.
Now lets get rid of that 1800TC, for a 2800. Now when you nail it, the Rs jump to lets say 203ftlbs which is 108 hp, a 67% improvement; before the addition of any headers or 4bbl.
See what I mean? 68hp versus 108hp,3% versus 67%; and without headers or a 4bbl.
The TC should be your first go-to.
My specific numbers could be wrong, but when expressed as a percentage. the point is the same ......... plus BIG %
And the car hasn't even started to move yet,lol
Lets see what happens as the tire makes it's first revolution.
First with the 1800TC and say 2.45 gears;
So out the crank is coming 190 ftlbs, and the trans multiplies that by 2.74 (A999), and the rear by 2.45, and the TC is gonna start off at 1.8-ratio. Ok so;
190x2.74x2.45x1.8=2300 ftlbs to the pavement, almost a chirp, maybe more like a squeaky suspension bushing, right?
Second with the 2800, and say 3.23s; Torque is up to 203 now (108hp). and,
203x2.74x3.23x1.8=3234 ftlbs now; So now, at 3234, you have broke the tires loose.
What's next?
That would be the sustain; can she keep spinning the tires?
Well the stocker cant hardly squawk one tire, never mind spinning them very far.
But with the 2800/3.23 combo;
as soon as the tires break traction, the 1.8 TM ratio drops to close to it's minimum, I'll guess 1.4, so;
203x2.74x3.23x1.4=2515, yeah, that should be plenty to sustain
The engine is now making 108hp and the rpm is rising. If you have kept your foot in it and the rpm has climbed to 3200 say to peak torque of 209, so 2590 ftlbs .
Ok well 2590 @3200 is a tuff call, as the car is accelerating, and torque is now gonna start to fall, I think she's done. 3200 @10%-slip will be 26mph, sounds about right.
So to recap;So far; the 2800TC and 3.23s have transformed your 318 into a tire shredder up to around 26 mph; a thing which the 4bbl and headers, by themselves could never do.
But we're not done yet; she's only up to 3200 rpm@26mph.
The factory 2bbl combo with single exhaust is gonna power peak at 4000 or so, which ,with 3.23s will be about 34 mph. But yur not gonna shift until 4400/37mph, so as to get the most out of first gear.
Compare the above combo, to the current combo with 2.45s.
3200 will NOT be until 35 mph! 4000 not until 44, and shift-rpm is 4400@48 mph.By 48mph, the 3.23s will be in Second at ~3260, having put down considerably more average power, and that means, considerably quicker in the doing.
And we still haven't touched the engine.
