Engine work
Well you really need to find out which block and head you have first we have seen some ES1 with same block style as A18/20 which would make it a lot easier for you to upgrade if it is.
Failing that if you are not lucky and have the early type block with ES1 head then your only option is ET1 head from Canadian Accord, or ET Head from non CVCC Prelude from Japan, Europe or Canada.
Now as for other options buy felpro headgasket this will allow you to fit larger pistons upto 83mm in size. You can buy Nissan CA18DET pistons from 200SX which can fit with some reworking to the valve pockets, or if you really shooting for big power with reliability then Brian Crower B16/18 Rods sportsman lightweight which are 100 grams less in weight, some titanium wrist pins, re bush the rods to 20mm and fit the Nissan Pistons or you can use the B16/18 pistons in a B20 oversize at 83mm but I'm not that keen on these as they have much larger valve pockets which reduce CR and also the crowns tend to be raised I prefer flat pistons or slight dish for better combustion and less stress on the head gasket. speaking of gasket again if you are really going for high CR ratio e.g. 11:1 to 12.5:1 your best bet is a Australian company that makes a MLS gasket for our cars they have the pattern already and are reasonably priced.
The inlet manifold can be custom made by a decent machine shop or you can pay for one from South Africa or New Zealand depeding on which head you end up with. Best carbs by far are the Webers as they are more widely supported and still available new in UK you can buy 45 DCOE's for £235 each but you'll need linkages and some jets and bits and bobs so total cost will work out a lot more.
Bearings you need to try and track down ACL bearings they do race series in big ends which are for B16/18 the Mains they only do tri metal range which are still very good but are out of production so hard to find and there are some mickey mouse Chinese copies out there. Other options are King Bearings which should be ok the mains take less of a pounding than the big ends. Rings I use Hastings rings buy oversize and hand gap them etc.
Camshaft you need to get re grind no one does a billet one can be done but at huge cost, but to be honest you can get very good power from 272 degrees duration or if you want it a little more revvy 285 degrees something along lines of 10-11mm lift is fine. Cam companies are Delta cheap and cheerful, Colt Cams (higher quality more thought on profiles), and Bisimoto again shoudl be better but have heard some have had grinds done and were not much better than stock duration making them next to useless. You do need to make sure you have the later style rockers fitted as the ones on early ES1 and ET were one piece hardened which tend to wear out and destroy the cams, the later ones fitted from 86 onwards have hardened material bonded to the rocker arm instead these can be refurbed smooth again with some careful work with wet and dry paper and dead flat surface.
Head work is where it gets really interesting the standard head isn't bad and the ports can be cleaned up nicely, the chambers too, the valves can be reprofiled to much better shape and more race orientated seats can be cut 5 angle with radius edges are the best but not many shops can do that very high end I tend to get 5 angle done then radius myself very carefully. Now where it can get very interesting is the valve seats are quite big an ET1 or ET head can take upto 33mm valve head an A20 or BT head can go to 32mm head not sure why they used slighty smaller seats on these two designs. Valves you can have custom made or if you end up with enough heads like me you can re machine exhaust valves to the size you want but you'll end up with thicker stems. What I'm looking at next time is to use Supertech valves which are the best off the shelf parts the ones for Honda D16 can be used (forget exact engine code) the stems are only couple mm short in height and lash caps can be used to make the difference up, the great thing is they come in 30mm, 31mm and 32mm head sizes and the stems are only 5.5mm thick and the valves are waisted and have a really nice race profile machined into them as standard. The exhaust valve is a little trickier you can leave as it is or just have Supertech make you a custom one 37mm is big enough to compensate for larger inlet valves I run 33mm intake and 37.5mm exhaust. Guides from other Honda engines can be made to fit and bought in bronze material using cast iron wears out fast with high lift cams. Again retainers and springs from other models can be used and titanium ones are not that pricey and will help reduce rotational and frictional losses.
Now tricky part is getting power down you need to ditch the auto it won't stand much more than 130bhp, best to find a 3rd gen Accord gearbox then a Integra gen 1 D16/ZC box use the bellhousing from the Accord and fit to the teggy box you can use a 2000 CIvic SI LSD inside as well, keep the accord gears for spares or use the 5th gear for taller cruising gear for better fuel economy or you may find once you get to a certain power level the accord gears are better for higher cruising speeds. Just make sure you use Honda MTF fluid and not engine oil!! You'll have to find a donor car that is a manual for pedals and clutch, engine rear mount and torque bar etc. the swap itself isn't that hard.
Brakes wise you can swap to SI knuckles and then fit Civic brakes including big brake kits from WIlwood etc. rears if you have drums I'd recommend swapping to disks from later donor car that you robbed gearbox parts from. Flywheel keep the 1.8 engine you can buy ally one from Clutchnet and uprated clutch from them, just make sure you get good fitment although myself and others haven't had issues someone in Aus had aligment issue with plate and they weren't too helpful generally I haven't found anywhere else that does off the shelf cluch that is as good as these they really can take a pounding if they are all built correctly.
Exhaust you need to make sure you have the 4-2 cast manifold if you don't and have the 4-1 you need to bin it, then find one from a later 3rd Gen Accord or 2nd Gen Prelude, or you can have one made up by a specialist. If you have 4-2 cast you can port it out and polish inside then fit 2" downpipes to a 2.5" collector and main system must be mandrel bent, if you only want upto 150bhp then go to 2.25" size. IF you get a tubular one made then I'd suggest 1.75" primaries and 2" secondaries and 2.5" collector. If you only want small power then Pacesetter does a 4-2-1 mild steel header with more conservative dimensions for smaller power outputs.
Think that's about it that's everything I've managed to remember and dig out for you to think about.
BTW my car makes 200bhp at 7600rpm and 160lbft at 5500rpm using stock Honda rods and NPR pistons. But I'll be looking to make a few changes to the head, carbs and exhaust manifold which should see me at around 220-230bhp and a lot more torque as well.
