Quote:More like an A14 with an A13 engine number. The A15 stroke is a lot larger than A13/A14 stroke.

sounds great! I'd love something similar for my 1200 coupe... you effectively have an a15 with a13 engine number. You would not need to go over the pits to get registered here in SA as theoretically you have not increased your engine size by more than 10%

The piston rods are chromoly and it was special made for this combination. I have a A14 oval port head that has toyota celica valves, double springs,ported to match either my fuel injection intake or my double weber intake ( yet deciding which one to use ), double angle on the valves and the head was cut to 80mm or something like that !!! Because the valves are to close to the pistons, the pistons where notched.This was already combined. I just bought the whole thing in pieces cause the shipping would be cheaper.I hope it runs good after finished

If this engine is now out to A14 or even A15 specs, then a switch to the larger oval port head from the regular [non Thrift version] A14 or an A15 head should ensure that standard A14 or A15 power ratings are achieved. This assumes that the compression ratio is up to snuff of course.

As I recall, the (1974) A13 used the small-oval ports. Hence more HP than an A12 with round ports.

Quote:I didn't say that it wasn't worth rebuilding, I said that if it needed a major overhaul, or reconditioning, then an A14 or A15 will be a worthwhile substitute, but if it was running fine, then leave it.
That's quite a bit different from what you suggest I said.

You say that you have it rebuilt already with A15 pistons? That's most interesting for the following reasons.
The 1974 A13 used 1200/A12 pistons of 73mm diameter & with the 17.5mm wrist pin.
The A15 piston is 76mm diameter, has a 2.5mm lower crown, or deck height, & uses a 19mm pin diameter.

The block should bore to 76mm OK & by using A14 or A15 rods, which are the same length as 1974 A13 rods, you could fit the A15 pistons without problems.
You could also bore out the small end of the 1974 A13 rod to fit, but this of course reduces the strength at this critical location.

What did you do when you found that the pistons fell short of the top of the block by 2.5mm?
This would reduce the compression by a fair bit & since the bowl volume in the A15 pistons is also greater than the A14 piston [which would have been the much better choice], this would reduce the compression even more.

If an A15 crank & oil pan was also installed at the rebuild, then the A15 pistons would be the right choice & you end up with an A15 engine that carries an A13 engine number prefix.

The 1974 A13 also has the larger valve sizes of 37 & 30mm but I do not know if the ports are the small oval size of the A12A head, or the larger oval size of the A14/15 head.
Hell, I can't even be sure that it doesn't use the round port head like the 'Thrift' version of the later A14's that are to be found in some US model 210's [B310]

Sure it is worth rebuilding.

However for the same money the 85 HP A14/A15 may better choice. During 79-82, there were 65 hp and 85 hp A14s. These are not only larger than A13s (although the same weight), but the 85 hp has larger intake ports, which make more power above 4,000 rpm.

Yes, I'm in the US. I was comparing hp on the engines from the A series and this is what I found:
73 A12 69HP @ 6000 70 Torque @ 4000
74 A13 75HP @ 6000 77 Torque @ 3600
75 A14 78HP @ 6000 75 Torque @ 4000
76-78 A14 80HP @ 6000 83 Torque @ 3600
79-82 A14 65HP @ 5600 75 Torque @ 3600
79-82 A15 67HP @ 5200 80 Torque @ 3200
This is from a US Repair Manual. So you say it's not worth rebuilding it ? I already have it with A15 pistons in it

Here we go again...

Quote:
Or a smaller bore A14.

The 1974 A13 as used in the US model B210 was a one-year-only offering & used the same 73mm bore size of the 1200 engine, but the taller block & longer 77mm stroke of the later A14.

Like all A series engines, it's a great design, but the 76mm bore of the 1975 A14 engine makes it just that much better.

If your A13 is in need of a major overhaul or worse, a recondition job, then a later a14 or A15 engine will be a worthwhile substitute.
If it's running fine, then leave it & enjoy motoring at it's economic best.