Hi guys, I have recently purchased an a15 race head, with big ports and twin dellorto sidedrafts for my existing a15 engine. The block is standard at the moment. Will I need to do anything to strengthen the bottom end or will I just be able to bolt her on and away I go?

Cheers

From what i know, assuming the ports are "big" so would the jets and chokes be on the carbies, therefore putting the head manifold and carbs in a top end power section. Possibly (without knowing specs) if the engine is a street engine it could flood the motor down low. However with a different cam it may smooth things out a bit and pickup some power down low.... but again depending on the cam you may be looking at a top end runner ie. over 5 grand because of highend air fuel flow.

Really depends on how many km's have been done on the bottom end and how much power extra power and the bigger bang you are adding to the pistons and con rods as you said bigger ports, twin dellorto so more fuel and air mixture bigger bang..

You should be able to just bolt it accross and off you go just depends on how long it will last and how hard you are going to drive it.. if you grandma around should be alright.

Really comes down to spec's as well.. how big are the valves? how big are the carbs? Cam? roller rockers ect. ect...

And what head is it?? oval port??

Maybe get the right cam to suit the carbs and up the comp to increase air flow wn low ,also do a comp test onthe motor befpr putting a new head on ,make sure the rings arnt stuffed co the carbs will be impossible to tune

and once you know your comp.ratio decide on the cam ,too big ad youll kill all the comp and be left with a motor that is crap down low and hard to tune ,and smaller chokes in the carbs will also make tuning heaps easyer and speed the air up at idle

Also if you have it stripped to the bototm end and you have the time and money, why not bore it 10-20 thou with a nice set of flat tops throw some fresh bearings in and a way you go... for a little extra kick ;)