Converters are so much different than they were 30 years ago. I know it’s a street car but from day one install a big cooler up from and reroute the lines to avoid your radiator cooler. Like you said hold off for now and plan out your engine combo and try to decide the percentage of track time it’s going to see. 3800 is small in my eyes and after seeing almost .5 in my sons duster going from a 4600 to a 5600 really opened my eyes. Both were good fresh converters.