hello...good question-but better than that is comment that Jesus loves you-thanks......
From my 0ver 25 years of working on Chevy 250 and 292's, i have found the MOST impressive performance gainer is to modify head with some form of Lump Port in Intake Port.....This seems to be a very touchy issue here on this Forum, but if you do not have a good flowing head, NO Other engine modifications will add as much as this....I truely do not understand why so many keep doing the same thing over and over expecting different results-but then again i do-I thought all the headers, cams, bigger carbs, and more Compression would change these engines , but until i was taught how to modify these heads, I just didnt "get it"...these stock heads work-they flow air- but until you change HOW they flow air,not much will change engine performance-.....I am sure there will be Many responses to this great question you have-I wasted lots of $$$$ on these engines till i found out about this and hope I can be of help to those you might appreciate this info....sounds like a fun, great project you have....

Lee