alrighty, i need good HP from my lil A series. i have talked about it many times b4 but i need to refine what im doing.

i have a A14 Block(i have to use a A14 block)

GX Head shaved to da max which has been fitted with A14 inlet & exhaust valves but im going bigger again (is that the right thing to do?)with better springs also what size are stock inlet & exhaust ports on gx heads cause i dont think my are standard

A15 Crank

Lighten flywheel

big cam (aparently i should use a 54/86 cam)

Twin 40mm delorto's with 32mm chokes

extractors

i will be boring the Block but how much can i go without thinning my bores too much? i will be using standard oversize pistons

i will also balance the bottom end
what sorts HP will i be reaching?

You haven't mentioned what the engine will be used for! I would hope it is a race engine (not for street use) with a cam that big. Thats a 320 degree duration cam and will only provide a benefit over smaller cams when the engine is reving 5000ish rpm upwards. If you shifting gears at 6000rpm for instance, you would be much quicker with a smaller cam.

You must set up your compression ratio. You mentioned you have shaved your head to the max. Have you cc'd the chambers ??

Twin dellortos with 32mm chokes should be good for only 6000ish rpm max. Thats perfect for a hot street motor and will give resonable low end performance.

You can bore most blocks safely to 78mm (expect if the block has heavy corrosion) and there are plenty pistons to suit.

HP??? Need more info....

If your chasing top end power I would also be using 36mm chokes in the sidedraughts 32mm as stated in the previous post would be great for say upto 6000RPM.

Benny

That raises an interesting question. Can you get 36mm chokes for 40mm webbers/dellorto?? I've never heard of them. The biggest I've heard of is 32mm chokes for 40mm carbs and 36mm chokes for 45mm carbs.

Dont bore it out to the max mine is only 1mm oversize just bore as far as you have to try to start with a virgin block. You want flat top hyperutectic pistons so mesure the standard piston & compare it to other pistons in the ACL catalog. Then fly cut them to clear bigger valves. DONT go to big in the cam specs you can go to big & you wont get the best resault in the end. 36mm chokes. If you go bigger valves then you will have to port the head to compensate for the bigger valves. Shaving the head isnt always the best way to get comp. Take the head to a pro & they will do the job properly & get the max performance out of it depending on how much you want to spend. 1K will get you somhing good
Coops

the motor will be for street use in a 1000ute. i sorta want atleast 140hp the parts i have so far compared to what i still have to get is
A14 Block
Gx head (shaved and fitted with A14 valves-JTS head)
Twin 40mm dellorto's of a alfa
i still have to get A15 crank, extractors, inlet manifold, cam and lighten Flywheel

140hp will get you into trouble on the steet in a 1000 ute
Thats why i only use mine on the race track.
Use a stock a14 bottom end,put that head on it with a 72 degree cam & your delorto carbs tune it properly & you will not disapointed in the resault. My car had twin 40mm webers on a stock a15 & that went well in a 1200. You have a 1000. Correct me if im wrong they weigh 650kg that will go very well.
Coops

Ny engine had a 54/86 cam and I would drive it on the road anyday, I idled nicely at 800rpm and went really well on the twin 40's I had. It had 106rwhp which is haps for the street and sounded sweet as...

for the larger valves,try l16 inlet & exhaust,the
only problem is they have to have the valve stem shortened,plus you need to run lash caps or the tops of the valve stems will wear(words of experience talking).any head shop should be able to shorten the valves,just take an inlet & an exhaust valve along as a sample.i got a set of 8mm lash caps from volksbahn at pendle hill
for $40.as for the 54/86 cam,i was less than impressed with it as both a race cam & a road cam,see if you can get something a little milder.you can bore the a14 block safely 2 mm over,which is a 78 mm piston,or 79mm with some blocks.i'd stick to the 78,because it'll allow you to rebore the block when it's worn out.balance the bottom end,shot-peen the conrods,get new rod bolts & crack detect them before using,get a new timing chain,get a gasmiser headgasket,which is a 79 mm diameter
& costs about $25.all this should make for a long lasting beast.now,what are we doing for brakes?

Quote:
Coops, you are absolutely right, in part, because you got the second part wrong.
My book says that the B20 Ute weighs 615kg & since the front half is the same as other 1000's, that weight reduction is over the back axle.
A balance of power & weight combined with suspension & brake improvements usually works well. Very bloody well.

Matto
Try to get the compression that you want from the pistons rather than weakening the head by excessive milling.
Mazda pistons [MX5?] seem popular & require very little modification to make them work in an A15 engine. These will give you a flat top & this results in a nice little boost in compression, even with an A14/15 head.

A well warmed A15 in a B20 Ute can give you good reason to buy brown underwear in bulk.