[aliendude012]

Hmmm. Generally the honda engines with the same letter/2 digit number code are ver very similar. aka the h22a, h22a1, and h22a4, are all very similar.

in this case, id say that parts for the j30a1 and a4 are interchangable, meaning as much as theyd fit. you mentioned the compression on the a4 being higher than the a1, and swapping internals into the a1 from the a4 will obviously alter the a1's compression. i'd be weary of swapping parts between the two. if you have the time and the interest, id say try it, give it a full leakdown and compression test, and see how things go. it'd probably be ok for a while, but those parts may wear a bit quickly.