2T/3T hybrid build questions

[ctrain]

Im about to build a hybrid and I have a few questions:

Do you use a 2t block or a 3t block? excluding internals

Which head is better a 2t or 3t head?

If I do chose to go with a twin cam head how do you make a pushrod block work with an DOHC head? how does the dizzy work without the cam? how does the timing gear work?

and once i sort all this out how much power atw will i make if i do the following: Note: this is with a reco 2t head

Bore it out to 89mm
Arias Forged High comp pistons (12.1)
Lightned flywheel
Twin 40mm webers
401a grind Cam
Vortex Porting with bigger valves
bronze valve guides
double valve springs
lightned rods

GearBox
W58

I know it might be a bit hard to come up with a power figure from just this info but im wondering wether i'd be better spending money and time on this N/A setup or going Turbo.

Cheers,
Callum

[stidnam]

If you are using a 3t crank in a 2t block then you will have to do some minor grinding of the sidewalls and bottom of the bores to create clearance for the increase stroke. There was a thread up a few months ago of someones build that showed how much they had to grind away.

A 3t block will not require grinding but will have the 3t engine number meaning telling your rego authority so you need to work out if this is considered a engine conversion that needs a engineers cert or not. In NSW it would be an owner certified mod.

Head wise between the 2/3tc and the 2tg the valves are bigger in the 2tg head so without any modifications you will get better head flow from the 2tg head. Issues you will encounter are that the upper timing guides for the 2tg are next to impossible to buy new these days. You can easily get the 2/3tc parts so availability will not be an issue.

The dissy bolts into the block so it will work with either the 2/3tc head or the 2tg head.

To make you 2/3tc a 3tg you need some items from the 2tg in addition to the head. You need the upper timing guides, timing cover, and the dummy cam. Also need to rotate back two cam bearings in the block to close off oil galleries. There are numerous posts on here that go into more details.

[ctrain]

So a dummy cam is put into the block so that the dizzy will still work if i go DOHC?

I'd rather stay with a 2t/3t head as im pretty familiar with them and parts are easy to come by, unlike the 2tg head

[caam]

Why 89mm? That's the limit of the blocks and will be cutting it close to water galleries etc.
If I remember correctly you've already brought cast pistons to suit standard size? stick with them, and save yourself $1000 odd for forged ones.
These motors respond very well from a lightened flywheel.

Hard to guess a power figured but i'd say around 80KW at the wheels going off of mine and other builts. all depends your specific build. (that being said mines a 2TG)

Cam

[ctrain]

well i have the chance to buy brad new forged 89mm high comps for under $500, im still not sure if i should stick with the 85mm's, i dont even know what the comp ratio is on them. i probablty will end up stick with the ones i have atm, but all these little bargains are popping up and im an impluse buyer :|