you may be able to use the stock v8 bellhousing from a task force truck or one of the cars. it needs to come from a vehile that uses the bell housing as the rear engine mount. this would hold up the rear of the engine if you have kept the stock crossmember behind the engine. thenyou would need to fab up some front engine mounts that would bolt onto the front face of the engine, like the v8 task force trucks used. this is all if your heidts crossmember allows the engine to fit at that height.
here is what the task force front engine mounts look like, they bolt to the cross member at the front of the engine bay and to the front face of the engine block
https://www.classicindustries.com/product/556038.html
this is what the v8 bell housing looks like, notice the ears for the rubber mounts. they used this style up to the mid 60's trucks, 66 I think, but not sure if they are all the same
https://www.ebay.com/itm/17591013103...BoCLCYQAvD_BwE