Well yeah they move heaps basically any way and the flanges allways need machining , it will get clamped to a big heavy plate with it bowed backwards slightly , then yeah weld the hard ones first , cut whole runners off if needed to get to welds , then the easy ones . Then i put it in the mill and run a fly cutter over the flanges .
I'm all for hopping up the 250, good engine to learn on. Solid and simple, no real snags when screwing them together.
You can delete the restrictive (and poorly placed) airflow meter/air cleaner from above the exhaust, plumb it to a cooler spot and run a later (MAFless) e-series computer with a J3 chip tune. Never done it but it's definitely a thing. E-series throttle body could be adapted (?), not sure how much cam the ECU will handle before chucking a shitty but not too much overlap, say a mild 208/208 on a 110 lobe angle would give brilliant midrange. Install better valvesprings, roller rockers (spacer needed on rocker cover if keeping the EFI one) extractors and 2.5" exhaust. 9.5 compression would be safe. Late model cat could easily be adapted.
The inlet manifold is OK, but the EA-ED log is better. If you know anyone who can TIG aluminium, you can graft one onto the injector plate that the bunch of bananas normally bolts to. This solves the problem of having to plumb up to the throttle body that's originally on top of the engine. Either that or make up some sort of adaptor plate for it.
on the plus side, the air defectors i made seem to work, car seemed 10 degrees cooler, weather may of played a part but still seems positive
hopefully can test it with aircon on 30 degree day and not over heat .. would be living the dream then