I've almost finished my 1200 ute I bought an engine with apparently 140-150hp
Does anyone know what I would get if I bolt a blow through setup or am I wasting my time

Don't do it ish not to that motor as its hi comp!

Haha yeah cheers man me and my mechanic are weighing up a few options how's the build going got any pics for me

I'm sure you could but if it was me I'd go for an injected setup with a turbo, carby turbos, while doable - are a real P.I.T.A. toyota had a real nice injected setup on the 7KE (which i compare to the datsun A series) which bolts on to most of the earlier motors. I think there was an injected A14, but I'm not sure which models had them. I've only ever seen A15s in forklifts which were all carby apart from the ones that have been fitted to early dattos. If you can solder okay you can get a meqasquirt setup for a few hundred bucks and it has programmability comparable to the ECUs costing 0000's as long as your slightly technically savvy and can work a laptop.

i would leave it. with that power your going to blow any a series gearbox and the amount of $ your going to spen u mite aswell put a different motor and gearbox in not to mention diff problems

If it's setup to make that sort of power NA, then apart from the compression ratio, the cam will have too much overlap (and likely too much duration) to be ideal as well. In very very very generalised terms, a cam that might make power up to (for example) 6500rpm, and run quickest with gearshifts at 6500rpm on a non turbo setup, might end up seeing the powerband extended to the point you are shifting at 7500rpm or so (possibly even more) assuming there's no other spanner in the works (like a restrictive turbo itself limiting flow beyond a certain point).

Aside from the compression, a well ported head for a turbo setup can differ a little bit, but yours would still (in all likelihood) work very well (flow wise). BUT one thing you would see dramatically different is that the exhaust valve to seat contact area (the thickness of where the two 45 degree angled sections of each actually touch when the valve is closed) for an NA engine is (relatively) thinner for improved flow, but a turbo engine needs thicker seat contact areas, because of the extra heat (not just because the turbo will trap more exhaust flow/heat than a set of extractors would, but also because under boost conditions, more air/fuel is being forced in in the first place, so there's more heat energy to deal with.

So even if you avoided detonation by running a decompression plate or dished pistons or whatever, and you went to a milder cam, you'll still likely run into issues with either the exhaust valves burning out prematurely, or even if that doesn't happen, the exhaust valve wouldn't be able to 'cool' on the seat, as the thinner seats don't transfer as much heat as quickly, so the exhaust valve runs hotter and hotter, and you end up with it causing pre-ignition, or possibly detonation. Either of which isn't a good thing naturally enough.

It might well be that the exhaust seats in question haven't been radically re-worked and aren't too thin for a turbo, but given you mention it's making about 150bhp, it's probably a good bet that they are too thin.

I'm guessing it's running webers or dellortos? They can be made to run blowthrough, but do need some tweaking to get the a/f curve right under boost whilst still being ok off boost. For a drag car, nobody would care if it was poor off boost with high fuel consumption etc, but for any other application, it will take some work.

I don't know if the page is still up (it's been some years since I've looked) but there was a bloke on the old mini-list and also the blowthruturbo list (which has more or less been dead for some years, and was renamed carbureted blowers) by the name of Jukka Harkola (iirc) - he had a turbo mini, and went from the mg metro blowthrough hif44 SU to a 45dhla (I think) dellorto. He spent ages getting it right, and no emulsion tube worked really well, despite massive development, and he ended up having to run restrictor plates at the carb mouths which didn't affect off boost fuel metering, but at high flow/boost, the slight restriction helped it richen up for full power, whilst still maintaining other settings which gave it good all round driveability etc)

Anyway point being, (if it does have webers or dellortos) they aren't the easiest carb in the world to fine tune for a blowthrough setup.

About the only option that comes to mind, is that you might be able to run e85 (if you can get it where you are posting from) and that might have high enough octane to run close to the current compression ratio but still allow 'some' boost safely.

140-150hp a series NA motor is super cool.is that at the wheels?
Leave it NA mate.

Highly unlikely to be at the wheels
I'd like to see a dyno of that one
Even 100 at the wheels is stout NA and unlikely to be able to run much boost without some engine mods to decompress and strengthen

thanks for all the replies ill post some pics i think you will all be impressed with the set up this engine is tough so ill post the dyno sheet once its done