can i use the B20A5 block from the 88-91 usdm prelude's for a B20/vtec. is there a difference from the b20b or the JDM B20Z.

 

yes, it can be done.

no, you don't want to do it...as the b20 lude block is probably the worst b-series motor honda ever built.

it would also require some work to get the head to bolt on...so its really just better to leave the lude motor in its place at the junkyard.

 

ok but will the other b-series vtec parts fit in it, like the oil pump and water pump. are the blocks the same as the new blocks

 

As a matter of fact! Putting a Vtec head is much the same as any other hybrid. The dowel pin holes on the intake side need to be drilled and a custom head gasket made. But Tuning it is a bitch. You'll only see about 128 whp BUT... Torque comes in at 112 ft.lbs at amazingly 2300 rpm and is pretty flat until 5800 where it starts to drop off. More power can be had by using H23A rods and B16 Vtec pistons but you'll need to have the pistons machined where the piston and rod connect, i.e. rod pins for fitment. If you want some more info check out
LUDESPEED.COM.

 

AND you can use a TYPE R oil pump. If you want to get injectors for that motor, you can use DSM Blue type (450cc) You'll need your ECU tuned because ANY B-series ecu wont run right at all with anything bigger than 310cc injectors.

Your better off building a custom turbo set up because the motor has a 9.0:1 C/R and with a vortech fmu and a T04E turbo and other fuel mods you could push upwards off 15 psi on a B20A5 in good condition. Good for about 190 whp and 150 ft.lbs of torque.

 

nathan atwell just described why you SHOULD NOT mess around with a b20a5 bottom end.

but i guess if being different and doing things the hard way is what you're looking to achieve then a b20a bottom end is what you want.

all i can say is good luck.

 

the b20a5 is not the same as the b20z. it has been attempted to put a vtec head onto a b20/b21 block, but never sucsefully finished...if im wrong please correct me. although b20/b21's do take turbos very well.

 

with all the info i got at luspeed.com it doesnt make me feel comfortable at all. i'll ust go for the b20b and save time and money.

that guy made power with an untued motor and blown head gasket. very impressive for what it was. b20 vtec makes good power