more power for my 403 smallblock

[mutzi]

hi, i´m a new user. i´m from germany.

i buy last year a 1978 olds delta88 with an 403 cid.
the engine is stock and i need more power for my car.

i read the compression of the stock 403 heads are the problem.
the edelbrock heads to expensive. i read in the internet: when i use 1972 olds 7a 350cid heads than i have more compression.

what i need even for tuning:
- is the stock rochester 4bbl carb. ok or is the edelbrock 1806 avs thunder 650cfm better?
- is the stock intake manifold ok or is the edelbrock 2711 performer better?

thanks you have really helped
mutzi