I've got a B18c1 head from a 1996 GSR and I'm wondering how does it compare in stock form to a B16a head?

 

Better cams and smaller combustion chamber volume for slight bump in compression. PR3 head "supposidly" flows more then the GSR head, but from the design I've seen the PR3 just has a smoother flow, as to where the GSR head has more of a velocity effect to it. Take it for what it's worth. I've seen both make power and both make more then the the other.

 

http://alaniztechnologies.com/...k.jpg
that's splitting hairs.
the PR-3 may do a very slightly better job than the B16, i would love to see a PR3-R vs PR3 (B16) comparison. there are some that speculate the R's slight job is just than, SLIGHT.

The GSR head will make more power because of the raise in compression....(in stock trim )

 

i personally prefer the P72 GSR head.

the ports are a bit higher than the PR3 head, so the airflow doesn't need to turn as much into the comb. chamber.

also as was mentioned the comb. chamber design is different yielding a bit higher C/R, about .2:1.

'supposedly' the PR3 heads flow better than the P72 head, but every test is a bit different. the PR3 head also is said to have larger intake ports compared to the P72. but the P72 has larger exhaust ports than the PR3. so you'll have to decide on one and then modify it to your needs/setup. P&P etc.

 

u guys covered it pretty well. im surprised to not see u guys mention the combustion chamber design. with goin all motor most ppl prefer the combustion chamber design of the P72 over the PR3 head. i think they call it a pentroof design which is "oval" in shape vs the PR3s more "rounded" combustion chamber. to avoid total reworking of the PR3 combustion chamber stick to the P72 that will need minimal reshaping.
also go look for pics of a serious racers PR3 head and u will notice the shape of the combustion chamber has been welded and shaped like a P72. just takes the guys more time to rework the PR3 head which translates to lost money from ur pocket.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">im surprised to not see u guys mention the combustion chamber design</TD></TR></TABLE>
well this thread was going on the same time:
https://honda-tech.com/zerothread?id=594489


the welding is usually at least $300

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Beave0101 &raquo;</TD></TR><TR><TD CLASS="quote">the welding is usually at least $300</TD></TR></TABLE>



yeah the P72 head's pentroof design is the way to go.
but spending all that $$ to have a PR3 head welded is just too much.

i personally never plan on getting rid of my P72 head to get a PR3 head.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1 2 NV &raquo;</TD></TR><TR><TD CLASS="quote">im surprised to not see u guys mention the combustion chamber design.</TD></TR></TABLE>

I'm pretty sure I mentioned this vaguely.