Going from the .16 to the .21 will require different motor mounts. I am not sure if you can use the CT4 mounts like the Fun Factors can. If you are not going to race competetively I sugget using the OS .18 motor. It will bolt right in and you can use the stock exhaust.

If the TR4 uses the same mounts as the FF's then you should be able to use the CT4 mounts and then switch to a big block. You will then need a new exhaust system and figure out what to do about clutch bells, Poor Judgement can help with this since he has done a big block swap.

I would personally stay with a small block. Mainly because parts availability can be difficult and the stock parts might not be able to handle the big blocks power.


rolland