Call IHPA. I just had my 152/clutch rebuilt through them. They provided a modified a 4cyl release bearing collar that press fits into the throwout bearing a couple of weeks ago. For some reason they dont have anything listed on their website for the 152 application.
I bought my Scout without the transmission bolted on the engine and some parts were lost. I think all I'm missing is the collar and bearing pressed. First time with a manual transmission installation, so I'm learning on the go.