318LA/906 SBE build it OR go Big block?

Hey guys I picked up a 74' DUSTER
It's a factory 318/906; AC car.
It has longtubes on it and a factor 8-1/4 rear end.

I posted on the BIG BLOCK swap section as well since I have a MOHO 440 that I could swap in the DUSTER.

However I also consider to keep the 318 (if it's a good runner)
Throw in a gasket /reseal kit, new rings and bearings if needed
And bolt on performance parts.

Iam not trying to touch the SBE besides the CAM/Lifters.
From here on I consider.
Cheap Alu heads.. like the SPEEDMASTERS.
-Do the stock rockers work on those?
-stock pushrods?

And a dual plane INTAKE
ELECTRONIC ignition/HEI

What carb size do you recommend? A 650cfm?
I would probably go vac sec, since it's mainly a street car.

* I can also get the oem heads fully ported , milled etc but it will be arround same price as the alu heads.

What can be expected from this mods?

I wonder what's more COST effective

1.440 (cammed sbe, heads are milled and valve jobbed) Single Plane intake.
NEEDS: Oilpan. Swap mounts. 727trans. Carb. Headers( insane 900+ $) accessories brackets
And all parts to make the PS and AC of the 318 bolt on and work.

OR
The mentioned 318 mods?

Or even find a ROLLER CAM 5 2/5.9 for cheap and build that on the side to swap out for the LA motor.
I assume the LA oilpan, accessories etc bolt onto the 5.2/5.9??

Help me to not swap it.
PS :IM ON MY BUDGET!
NO I WILL NOT BUILD A FULL OUT ENGINE.
it will be a BUDGET approach .

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