I want to get some 280-300 horsepower out of 305 tbi. and No i am not getting 350 for many reasons, mostly cause finnish government.
what to do?heads cam intakemanifold cold air intake and headers? enough?bigger tbi and/or fuel pump?should i buy aluminium heads or not?

 

you will need new heads/cam/intake, and at least a 670cfm throttle body. you are also going to need quite a bit of computer work, the cam it is going to take to get you into that HP range is not going to be incredable computer friendly. it will need lots of tuning.

 

You will need to replace everything but the stock short block.

Larger TBI unit with larger injectors and high volume fuel pump.
Any heads other than stock. Depending on emmsions and tuning and egr and such your choices are plentifull.
Full exhaust with headers, high flo cat and cat back.
Carb intake with adapter plate (do not go to big here remember it is a 305).
And most inportantly is the amount of tuning you will need. You will tune till you are blue in the face only to find out more tuning will make it run even better.

 

What restrictions does the Finnish gov't put on the car/engine? Is this a matter of passing emmisions or is there a visual engine bay check or both?
What I'm getting at is if you intend to stick with the 305 block, would you consider a stroker kit to increase displacement-along with mods mentioned by ShiftyCapone, or is this unacceptable solely for emissions reasons?
Pulling an engine/trans combo is work, but not nearly as back breaking as bending over your engine bay for days while installing cam/heads/intake/exhaust manifolds. Having the engine out and on a stand during rebuild or mod also makes it alot easier to do a good job. Sometimes it is best to get it out of the car and perform all work at once.
If you are looking to leave the engine in place and wish only a cam/head/manifold package, Edlebrock has a package deal. It is lame and leaves a lot on the table in my opinion, but they are in California and have to play by different rules there. I have to pass emissions here in Chicago as well, but I believe that California's emssions are more strict.

For conversation- what are the emmisions standards over there in Finnland? What is the price of fuel?

S-D

 

OK... use my list... I have WELL OVER 300 HP out of a 305 TBI, and it's street legal
AND I used the stock block....
First you need a GOOD cam.. the cam is the "HEART" of the ENGINE.... you can use an LT1 cam,... it's "mid-range" and will be a HUGE improvement for a 305.. but is more on the side of mileage.. or get a comp roller cam (08-501-8, or more radical 08-502-8) these are BOTH good cams, which will allow for MUCH MORE POWER.. they WILL work with your computer and remain emissions legal.
You also need good heads... heads are like the "lungs" you need them to allow the power from the cam to be used... there are several heads that you can choose for a 305 that will work (World Product SR torquer 305's... vortecs.. 350 heads ... for the later 2 you will need bigger springs, and a decent port job and probably bigger valves...
next... the INTAKE... you should probably get the edelbrock TBI performer ... if you use an injector spacer and do the "ultimate TBI mods" and adjust the fuel pressure reg... you SHOULD be able to keep the stock injectors BUT you WILL need computer chip tuning to do that (get a custom chip from www.tbichips.com) the guys name is brian, he's cheap and REALLY good
HEADERS are VERY important in making big power... get a pair of headers, a good y-pipe, a 3" cat-back ... and with all that .. you should be good to go
Any questions... let me know... you want pics... let me know
I have a very similar set up and my 305 is pushing about 340 HP, and about 400 ft/lbs. of torque (at the engine)

 

have any dyno sheets to prove this?

i am not calling BS, but claiming 340 HP out of a 305 is pretty bold. especialy considering the 2 cams you mentioned above, and the fact you are still using only small block TB unit.

although the 10-502-8 cam is a pretty nice cam for a 305 comprebale to the ZZ4 cam listed in your sig, i don't see it as a good match for the stock TB, i would imagine judging by the sig you have, that you aren't at the 340 mark. unless that number was one you came up with in desktop dyno