Iv seen plenty of threads about it working but couldn't find anyone who has actually done it first hand. Will an 04 ap2 block work with my 2000 ap1 heads and ecu. All internals are stock.

 

Yes....the heads between AP1 and 04-05 AP2 are identical. I'd be cautious of going over 8200 RPM though even though your ECU will allow you to go to 9K.

 

So should I get the ap2 ecu or an extra 100 ? Jut to be on the safe side ? And will the ap2 plug up to ap1 harness ?

 

Use the 2000-2001 ECU if that's not what you already have.... use your AP1 harness. I would recommend upgrading the retainers in the AP1 head to AP2 if you haven't already done so. Also, as stated, don't get comfortable revving to 9K all day every day. Once or twice is okay, but it'd be best not to.

This thread has a lot of useful info.... https://www.s2ki.com/s2000/topic/832...ith-ap2-motor/

 

Also, when I say the heads are identical. I mean the casting. There are differences with the retainers and the cams, but don't worry about those if you follow my advice and upgrade to AP2 retainers.

 

Nice thanks I'll be using the ap1 tranny as well. So is changing the retainers a must or is it just recommended ?

 

It's a must in the sense that they are much more resilient and resist cracking, unlike the AP1 retainers. They're just plain better. If I were doing this swap, the AP2 retainers would be a given.

 

I've restarted that thread with a question.

 

Also should I get new studs or just keep stock ones ? I was readin that stock loose their clamping force after removed ?

 

Measure them.... most of the time the stock head bolts can be reused at least once. I've personally reused multiple sets without issue. I'm sure you'll be fine.