Are the B20A/B21A Mounts the same as the rest of the B series motors?

Im toying around with the idea of destroking a B20A/B21A block with either a 89mm or 92mm crank and building it as a non VTEC Boosted set up for a friend of mine. I know the B20A/B21 motors can run cams from the LS and Ive heard of some even running LS IM's so that is a plus in terms of aftermarket cam and IM choices. Is the Exhaust flange the same? If so that would mean Turbo manifolds and headers are readily available.

Im just looking into this to possibly drop in a friends EK, he has both the B21 and B20A sitting in his garage left over from his 91 Prelude Si days. Just trying to possibly do something new.

Any info?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Altered &raquo;</TD></TR><TR><TD CLASS="quote">Are the B20A/B21A Mounts the same as the rest of the B series motors?</TD></TR></TABLE>

The mounting from the old B20/B21 Prelude's are completely different from the B16A, B18C etc. An Aftermarket mount company (Place Racing I think) was even working on a mount kit to fit the newer B series into the 88-91 Prelude's. It's not a popular application so I don't know if they went through and completed them.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I know the B20A/B21 motors can run cams from the LS and Ive heard of some even running LS IM's so that is a plus in terms of aftermarket cam and IM choices. Is the Exhaust flange the same? If so that would mean Turbo manifolds and headers are readily available.</TD></TR></TABLE>

Are you sure that you aren't getting the old Prelude motors confused with the newer B20B/Z CRV motors? The CRV B20 uses the same head as a 94-01 LS Integra so you can swap cams and manifolds which is usually necessary for hood clearance in another chassis. I've never heard of any of the parts you mentioned being compatible with the older B20/B21 Prelude motors.

 

Ive seen a few posts here and there on prelude forums of people using or wanting to use crower LS cams in those older motors. So Im just going off of that.