[TatII]

there is really no concrete evidence of the KA head flowing better then a SR head. but from what i've read in the past is that someone has spend almost 1000 on a full head and valve on the KA and got minimal gains in return. this is our assumption that the KA head flows damn good even in stock form. now compared to SR's we really have no clue. i'm pretty sure the KA head will flow better then the low port SR heads found in the S14 and S15 SR's. but compared to the high port S13 SR's the flow should be about the same.

what makes the SR a better boosted motor? well the only true reason i can think off is that it comes with lower and forged pistons right off bat. if you change the pistons on the KA to forged units then the strenght difference between them are a toss up.

the SR has a closed deck aluminum block, the KA has a closed deck iron block. the SR has piston cooling oil squirters, the KA has the same thing. both engines have forged cranks, with the KA having a thicker crank by the main bearings. again as mentioned the main weakness is the piston of hte KA. Ivan from performance and sound has taken stock KA's up to 400whp. and at this point is where the ring lands crack on the pistons from just the stress of the pressure, not from detonation.

the SR has a better high rpm motor since it rev's to 7.5 K stock and somes with a pretty small turbo. this gives it a power band thats around 4.5K broad. the KA has a better valve train since it has no rocker arms to fly out, but the KA has waaay more stroke then a SR. the SR's bore and stroke are perfectly even. its a perfectly squared engine.

the KA's piston bore is 89mm and the stroke is 96mm's. that compared to the SR's 86mm x 86mm bore and stroke, and you'll see that hte KA's stroke is a whole 10mm longer!! so therefore the head can support the high rpm's the rotating assembly unfortunatly cannot.

i mean you really can't go wrong with either engines. its just up to how you like to do things. it actually takes alot more skills to turbo a KA and keep it running compared to just swapping a engine thats already turboed from the factory.