D4MJT;1192440 said:
From what I've read, it makes no sense to rebuild the engine without using a metal head gasket for the rebuild, is this correct?
A MHG is what you want, but it requires a very smooth block/head deck...the HKS Stopper is without a doubt the best. Second is the bead type, HKS or Cometic. The bore will depend on if you go with oversize pistons and the thickness will depend on how much material is removed form the block and head decks.
ARP studs are the way to go...torque to ARP specs (on the sheet that comes with them).
D4MJT;1192440 said:
I've been looking at OEM Toyota re-build kits, which include gasket seals, bearings, shells, etc for a rebuild, is this a good option, or would I be better off using aftermarket parts?
I used Toyota OEM complete gasket kits...the best IMO. Some of the aftermarket kits are good, but you will need to replace some of the gaskets. The exhaust manifold gasket comes to mind.
D4MJT;1192440 said:
My aim with the engine is to have a more powerful engine I can tune, I would like to rebuild it to be capable of at least 300bhp, ideally more, but I also don't want to be too ambitious on my first build, and also there's the age old issue of money.
Stick with stock parts to the extent you can....machine work will be the major cost. Have the crank trued, balanced and the journals resized/polished. A line bore on the block mains, resizing to match the crank main journals is a good idea. ARP main bolts are up to you...the stock bolts are pretty strong.
Have the rod crank ends resized/trued to use std size bearings to match the crank journals if possible and have the rods shot preened. ARP rod bolts are an excellent investment. I would go with forged pistons.
For the head, a 3 angle valve job, replace seals and guides is minimum. If you want more flow, oversize valves and a port job. I would upgrade the springs with Comp Cam valve springs (they are for a SBC)...you can use the stock seats and retainers.
D4MJT;1192440 said:
I've also read the stock transmission (A340E) will take 350bhp before it starts to run into problems, is this correct? What do you do when you want to put more power through, does the manual box with a decent clutch take a lot more?
Above ~350 HP or so you can either build the A340E to handle more HP or do a manual swap to the R154 (it can handle 500 HP easily). The A340E rebuild is a lot more expensive, but it has advantages in terms of driving and building a constant boost curve. It all depends on personal choice.
D4MJT;1192440 said:
At 147,000 miles, I'm expecting my turbo to be on it's way out with plenty of play, I can see nothing to suggest it's been replaced or rebuilt, so I'm assuming it's original, I understand that I'll need to have a far clearer idea of what spec I'm building the engine to, before I choose what to do with regards to the turbo, ie once I've got the small block built, I'll have a better idea of what turbo will suit it best, is this right or should I be considering my turbo choice and building the small block around that?
Choose the turbo for what you want to do...quick spool, top end power, etc. The manifold, IC, piping and TB all are restrictions and have to be factored in. The BOSS series turbos are good for a stock manifold install...others like the GT35R are going to require a new manifold or and adapter. For your goals, the BOSS is the way to go.