to put one in - youd obviously need ot swap over to now engine mounts - and hope it all fits
Downside of this conversion so ive heard is the extra weight of the 18rg upsets the balance of the front end of the ta22 - makes it more nose heavy
As others have said - 2tg is your best bet if you want twin cams and an easy conversion - as it is just " bolt in "
power wise the 18rg - in high compression carb form puts out about 145 fwhp , a 2tg - 125fwhp - so your not loosing out much on power on stock motor outputs ..
Decent cams - and tuning will see a 2tg up there with the RG's PLUS you can stroke them out to 1.8 litres with a 3t crank swap !
and out to 2 litres i believe with a overbore ( 86mm ?) and suitable pistons ..